2,128 results on '"B. Howell"'
Search Results
2. PP 1.14 – 00094 Development of an immunocytochemistry assay to quantify the translationally active HIV reservoir
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G. Wu, R. Walters, Y. Li, J. Kristoff, C. Cheney, J. Maxwell, Q. Huang, T. Diamond, P. Zuck, C. Balibar, J. Grobler, B. Howell, and L. Sardo
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2022
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3. Evaluation of IAP/SMAC mimetics as latency reversal agents in primary cells and cytokine induction in in vivo models predictive of cytokine release
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B. Howell, W. Shipe, G. Adam, S. Quan, L. Li, C.N.A. Sim, R. Dunham, D. Margolis, B. Henry, and D. Hazuda
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2019
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4. Distinct HIV reservoir measures correlate with defective but not intact pro-viral DNA
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E. Papasavvas, L. Azzoni, P. Tebas, K. Mounzer, J.R. Kostman, D. Richman, N. Chomont, B. Howell, and L.J. Montaner
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2019
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5. PD-1 blockade boost vaccine-induced anti-HIV responses in the absence of HIV reactivation
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J.G. Prado, M. Marin Lopez, E. Jimenez-Moyano, D. Ouchi, O. Blanch-Lombarte, D. Gorman, T. Hanke, C. Brander, B. Howell, and B. Mothe
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2019
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6. Baseline inducible HIV P24 is associated with viral control during interferon-α monotherapy with ART interruption
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L.J. Montaner, L. Azzoni, E. Papasavvas, P. Tebas, K. Mounzer, B. Howell, D. Holder, N. Chomont, L. Kuri Cervantes, and M. Betts
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2019
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7. Cellular modulation and HIV reactivation in response to serial treatment of latently HIV infected CD4 T cells with histone deacetylase inhibitors (HDACi)
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J. Maxwell, A. Nefedov, C. Dorfmeier, G. Wu, Y. Li, P. Zuck, D. Hazuda, A. Webber, R. Barnard, and B. Howell
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2019
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8. CD32+ CD4+ T Cells are HIV transcriptionally active rather than a resting reservoir
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M. Abdel-Mohsen, C. Tomescu, S. Vadrevu, A. Spivak, L. Kuri-Cervantes, G. Wu, K. Cox, S. Vemula, M. Fair, K. Lynn, M.J. Buzon, J. Martinez-Picado, M. Betts, V. Planelles, K. Mounzer, B. Howell, D. Hazuda, P. Tebas, and L.J. Montaner
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2017
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9. Slc35a2 mosaic knockout impacts cortical development, dendritic arborisation, and neuronal firing
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James Spyrou, Khaing Phyu Aung, Hannah Vanyai, Richard J. Leventer, Snezana Maljevic, Paul J. Lockhart, Katherine B. Howell, and Christopher A. Reid
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Epilepsy ,Cortical malformation ,Cortical dysplasia ,Neurodevelopment ,CRISPR ,Glycosylation ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) is an important cause of drug-resistant epilepsy. A significant subset of individuals diagnosed with MOGHE display somatic mosaicism for loss-of-function variants in SLC35A2, which encodes the UDP-galactose transporter. We developed a mouse model to investigate how disruption of this transporter leads to a malformation of cortical development. We used in utero electroporation and CRISPR/Cas9 to knockout Slc35a2 in a subset of layer 2/3 cortical neuronal progenitors in the developing brains of male and female fetal mice to model mosaic expression. Mosaic Slc35a2 knockout was verified through next-generation sequencing and immunohistochemistry of GFP-labelled transfected cells. Histology of brain tissue in mosaic Slc35a2 knockout mice revealed the presence of upper layer-derived cortical neurons in the white matter. Reconstruction of single filled neurons identified altered dendritic arborisation with Slc35a2 knockout neurons having increased complexity. Whole-cell electrophysiological recordings revealed that Slc35a2 knockout neurons display reduced action potential firing, increased afterhyperpolarisation duration and reduced burst-firing when compared with control neurons. Mosaic Slc35a2 knockout mice also exhibited significantly increased epileptiform spiking and increased locomotor activity. We successfully generated a mouse model of mosaic Slc35a2 deficiency, which recapitulates features of the human phenotype, including impaired neuronal migration. We show that knockout in layer 2/3 cortical neuron progenitors is sufficient to disrupt neuronal excitability, increase epileptiform activity and cause hyperactivity in mosaic mice. Our mouse model provides an opportunity to further investigate the disease mechanisms that contribute to MOGHE and facilitate the development of precision therapies.
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- 2024
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10. In vitro analysis of different PKC agonists: latency reversal, T-cell activation, cytokine production and isoform selectivity
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R. Barnard, D. Tellers, B. Howell, E. Cook, M. Swanson, S. Vemula, J. Li, S. Carroll, and D. Hazuda
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Microbiology ,QR1-502 ,Public aspects of medicine ,RA1-1270 - Published
- 2015
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11. The dynamic universe: realizing the potential of classical time domain and multimessenger astrophysics
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Steve B. Howell, D. Andrew Howell, R. A. Street, Melinda Soares-Furtado, Brian Jackson, and Thomas P. Greene
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time-domain astronomy ,multi-messenger astronomy ,time-series observations ,phase-resolved observations ,multi-wavelength observations ,Astronomy ,QB1-991 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
In parallel with the multi-messenger revolution, major advances in time-domain astronomy across multiple science disciplines relevant to astrophysics are becoming more urgent to address. Aside from electromagnetic observations of gravitational wave events and explosive counterparts, there are a number of “classical” astrophysical areas that require new thinking for proper exploration in the time domain. How NASA, NSF, ESA, and ESO consider the 2020 USA Decadal Survey within the astronomy community, as well as the worldwide call to support and expand time domain and multi-messenger astrophysics, it is crucial that all areas of astrophysics, including stellar, galactic, Solar System, and exoplanetary science participate in the discussion, and that it not be made into an exclusive preserve of cosmological, high-energy, explosive and transient science. Time domain astronomy is used to explore many aspects of astrophysics–particularly concerning ground- and space-based mission science goals of exploring how the Universe works, understanding how did we get here, and are we alone. Time domain studies are already built into the core operations of many currently operating and future space telescopes (e.g., Roman, PLATO) as well as current and planned large areal ground-based surveys (e.g., Rubin). Time-domain observations designed for one scientific purpose, also lead to great discoveries in many other science areas. The recent advent of user-friendly hardware, software, observational approaches, and online data infrastructure has also helped make time domain observations especially suitable and appealing for citizen science projects. We provide a review of the current state of TDAMM alerts and observational protocols, revealing a wide array of software and applications, much of which is incompatible. Any conversation regarding TDAMM astrophysics should include all aspects of the field, including those aspects seen as classical applications.
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- 2024
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12. A 1.55 R⊕ habitable-zone planet hosted by TOI-715, an M4 star near the ecliptic South Pole
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Georgina Dransfield, Mathilde Timmermans, Amaury H M J Triaud, Martín Dévora-Pajares, Christian Aganze, Khalid Barkaoui, Adam J Burgasser, Karen A Collins, Marion Cointepas, Elsa Ducrot, Maximilian N Günther, Steve B Howell, Catriona A Murray, Prajwal Niraula, Benjamin V Rackham, Daniel Sebastian, Keivan G Stassun, Sebastián Zúñiga-Fernández, José Manuel Almenara, Xavier Bonfils, François Bouchy, Christopher J Burke, David Charbonneau, Jessie L Christiansen, Laetitia Delrez, Tianjun Gan, Lionel J García, Michaël Gillon, Yilen Gómez Maqueo Chew, Katharine M Hesse, Matthew J Hooton, Giovanni Isopi, Emmanuël Jehin, Jon M Jenkins, David W Latham, Franco Mallia, Felipe Murgas, Peter P Pedersen, Francisco J Pozuelos, Didier Queloz, David R Rodriguez, Nicole Schanche, Sara Seager, Gregor Srdoc, Chris Stockdale, Joseph D Twicken, Roland Vanderspek, Robert Wells, Joshua N Winn, Julien de Wit, and Aldo Zapparata
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- 2023
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13. Glomangiopericytoma: a case series with review of literature
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Aasif A. Kazi, Elizabeth M. McDougal, Jessica B. Howell, Theodore A. Schuman, and Ryan S. Nord
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Otorhinolaryngology ,RF1-547 - Published
- 2022
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14. Searching for GEMS: Characterizing Six Giant Planets Around Cool Dwarfs
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Shubham Kanodia, Arvind F. Gupta, Caleb I. Cañas, Lia Marta Bernabò, Varghese Reji, Te Han, Madison Brady, Andreas Seifahrt, William D. Cochran, Nidia Morrell, Ritvik Basant, Jacob Bean, Chad F. Bender, Zoë L. de Beurs, Allyson Bieryla, Alexina Birkholz, Nina Brown, Franklin Chapman, David R. Ciardi, Catherine A. Clark, Ethan G. Cotter, Scott A. Diddams, Samuel Halverson, Suzanne Hawley, Leslie Hebb, Rae Holcomb, Steve B. Howell, Henry A. Kobulnicky, Adam F. Kowalski, Alexander Larsen, Jessica Libby-Roberts, Andrea S. J. Lin, Michael B. Lund, Rafael Luque, Andrew Monson, Joe P. Ninan, Brock A. Parker, Nishka Patel, Michael Rodruck, Gabrielle Ross, Arpita Roy, Christian Schwab, Guđmundur Stefánsson, Aubrie Thoms, and Andrew Vanderburg
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Extrasolar gaseous giant planets ,Radial velocity ,M dwarf stars ,Transits ,Astronomy ,QB1-991 - Abstract
Transiting giant exoplanets around M-dwarf stars (GEMS) are rare, owing to the low-mass host stars. However, the all-sky coverage of TESS has enabled the detection of an increasingly large number of them to enable statistical surveys like the Searching for GEMS survey. As part of this endeavor, we describe the observations of six transiting giant planets, which include precise mass measurements for two GEMS (K2-419Ab, TOI-6034b) and statistical validation for four systems, which includes validation and mass upper limits for three of them (TOI-5218b, TOI-5616b, TOI-5634Ab), while the fourth one—TOI-5414b is classified as a “likely planet.” Our observations include radial velocities from the Habitable-zone Planet Finder on the Hobby–Eberly Telescope, and MAROON-X on Gemini-North, along with photometry and high-contrast imaging from multiple ground-based facilities. In addition to TESS photometry, K2-419Ab was also observed and statistically validated as part of the K2 mission in Campaigns 5 and 18, which provide precise orbital and planetary constraints despite the faint host star and long orbital period of ∼20.4 days. With an equilibrium temperature of only 380 K, K2-419Ab is one of the coolest known well-characterized transiting planets. TOI-6034 has a late F-type companion about 40″ away, making it the first GEMS host star to have an earlier main-sequence binary companion. These confirmations add to the existing small sample of confirmed transiting GEMS.
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- 2024
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15. Gemini High-resolution Optical Spectrograph (GHOST) at Gemini South: Instrument Performance and Integration, First Science, and Next Steps
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V. M. Kalari, R. J. Diaz, G. Robertson, A. McConnachie, M. Ireland, R. Salinas, P. Young, C. Simpson, C. Hayes, J. Nielsen, G. Burley, J. Pazder, M. Gomez-Jimenez, E. Martioli, S. B. Howell, M. Jeong, S. Juneau, R. Ruiz-Carmona, S. Margheim, A. Sheinis, A. Anthony, G. Baker, T. A. M. Berg, T. Cao, E. Chapin, T. Chin, K. Chiboucas, V. Churilov, E. Deibert, A. Densmore, J. Dunn, M. L. Edgar, J. Heo, D. Henderson, T. Farrell, J. Font, V. Firpo, J. Fuentes, K. Labrie, S. Lambert, J. Lawrence, J. Lothrop, R. McDermid, B. W. Miller, G. Perez, V. M. Placco, P. Prado, C. Quiroz, F. Ramos, R. Rutten, K. M. G. Silva, J. Thomas-Osip, C. Urrutia, W. D. Vacca, K. Venn, F. Waller, L. Waller, M. White, S. Xu, and R. Zhelem
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High resolution spectroscopy ,Astronomical instrumentation ,Optical observatories ,Astronomy ,QB1-991 - Abstract
The Gemini South telescope is now equipped with a new high-resolution spectrograph called the Gemini High-resolution Optical SpecTrograph (GHOST). This instrument provides high-efficiency, high-resolution spectra covering 347–1060 nm in a single exposure of either one or two targets simultaneously, along with precision radial velocity spectroscopy utilizing an internal calibration source. It can operate at a spectral element resolving power of either 76,000 or 56,000, and can reach a signal-to-noise ratio of ∼5 in a 1 hr exposure on a V ∼ 20.8 mag target in median site seeing and dark skies (per resolution element). GHOST was installed on-site in 2022 June, and we report performance after full integration to queue operations in 2023 November, in addition to scientific results enabled by the integration observing runs. These results demonstrate the ability to observe a wide variety of bright and faint targets with high efficiency and precision. With GHOST, new avenues to explore high-resolution spectroscopy have opened up to the astronomical community. These are described, along with the planned and potential upgrades to the instrument.
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- 2024
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16. TOI 762 A b and TIC 46432937 b: Two Giant Planets Transiting M-dwarf Stars
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Joel D. Hartman, Daniel Bayliss, Rafael Brahm, Edward M. Bryant, Andrés Jordán, Gáspár Á. Bakos, Melissa J. Hobson, Elyar Sedaghati, Xavier Bonfils, Marion Cointepas, Jose Manuel Almenara, Khalid Barkaoui, Mathilde Timmermans, George Dransfield, Elsa Ducrot, Sebastián Zúñiga-Fernández, Matthew J. Hooton, Peter Pihlmann Pedersen, Francisco J. Pozuelos, Amaury H. M. J. Triaud, Michaël Gillon, Emmanuel Jehin, William C. Waalkes, Zachory K. Berta-Thompson, Steve B. Howell, Elise Furlan, George R. Ricker, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, David Rapetti, Karen A. Collins, David Charbonneau, Christopher J. Burke, and David R. Rodriguez
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Exoplanet systems ,Exoplanet astronomy ,Transit photometry ,Radial velocity ,Space telescopes ,M dwarf stars ,Astronomy ,QB1-991 - Abstract
We present the discovery of TOI 762 A b and TIC 46432937 b, two giant planets transiting M-dwarf stars. Transits of both systems were first detected from observations by the NASA TESS mission, and the transiting objects are confirmed as planets through high-precision radial velocity observations carried out with Very Large Telescope/ESPRESSO. TOI 762 A b is a warm sub-Saturn with a mass of 0.251 ± 0.042 M _J , a radius of 0.744 ± 0.017 R _J , and an orbital period of 3.4717 days. It transits a mid-M-dwarf star with a mass of 0.442 ± 0.025 M _☉ and a radius of 0.4250 ± 0.0091 R _☉ . The star TOI 762 A has a resolved binary star companion, TOI 762 B, that is separated from TOI 762 A by 3.″2 (∼319 au) and has an estimated mass of 0.227 ± 0.010 M _☉ . The planet TIC 46432937 b is a warm super-Jupiter with a mass of 3.20 ± 0.11 M _J and radius of 1.188 ± 0.030 R _J . The planet’s orbital period is P = 1.4404 days, and it undergoes grazing transits of its early M-dwarf host star, which has a mass of 0.563 ± 0.029 M _☉ and a radius of 0.5299 ± 0.0091 R _☉ . TIC 46432937 b is one of the highest-mass planets found to date transiting an M-dwarf star. TIC 46432937 b is also a promising target for atmospheric observations, having the highest transmission spectroscopy metric or emission spectroscopy metric value of any known warm super-Jupiter (mass greater than 3.0 M _J , equilibrium temperature below 1000 K).
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- 2024
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17. TIC 290061484: A Triply Eclipsing Triple System with the Shortest Known Outer Period of 24.5 Days
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V. B. Kostov, S. A. Rappaport, T. Borkovits, B. P. Powell, R. Gagliano, M. Omohundro, I. B. Bíró, M. Moe, S. B. Howell, T. Mitnyan, C. A. Clark, M. H. Kristiansen, I. A. Terentev, H. M. Schwengeler, A. Pál, and A. Vanderburg
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Multiple stars ,Binary stars ,Eclipsing binary stars ,Close binary stars ,Astrophysics ,QB460-466 - Abstract
We have discovered a triply eclipsing triple-star system, TIC 290061484, with the shortest known outer period, P _out , of only 24.5 days. This “eclipses” the previous record set by λ Tauri at 33.02 days, which held for 68 yr. The inner binary, with an orbital period of P _in = 1.8 days, produces primary and secondary eclipses and exhibits prominent eclipse timing variations with the same periodicity as the outer orbit. The tertiary star eclipses, and is eclipsed by, the inner binary with pronounced asymmetric profiles. The inclinations of both orbits evolve on observable timescales such that the third-body eclipses exhibit dramatic depth variations in TESS data. A photodynamical model provides a complete solution for all orbital and physical parameters of the triple system, showing that the three stars have masses of 6.85, 6.11, and 7.90 M _⊙ , radii near those corresponding to the main sequence, and T _eff in the range of 21,000–23,700 K. Remarkably, the model shows that the triple is in fact a subsystem of a hierarchical 2+1+1 quadruple with a distant fourth star. The outermost star has a period of ∼3200 days and a mass comparable to the stars in the inner triple. In ∼20 Myr, all three components of the triple subsystem will merge, undergo a Type II supernova explosion, and leave a single remnant neutron star. At the time of writing, TIC 290061484 is the most compact triple system and one of the tighter known compact triples (i.e., P _out / P _in = 13.7).
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- 2024
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18. The TESS-Keck Survey. XXII. A Sub-Neptune Orbiting TOI-1437
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Daria Pidhorodetska, Emily A. Gilbert, Stephen R. Kane, Thomas Barclay, Alex S. Polanski, Michelle L. Hill, Keivan G. Stassun, Steven Giacalone, David R. Ciardi, Andrew W. Boyle, Steve B. Howell, Jorge Lillo-Box, Mason G. MacDougall, Tara Fetherolf, Natalie M. Batalha, Ian J. M. Crossfield, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Howard Isaacson, Erik A. Petigura, Paul Robertson, Lauren M. Weiss, Isabel Angelo, Corey Beard, Aida Behmard, Sarah Blunt, Casey L. Brinkman, Ashley Chontos, Fei Dai, Paul A. Dalba, Rae Holcomb, Jack Lubin, Andrew W. Mayo, Joseph M. Akana Murphy, Malena Rice, Ryan Rubenzahl, Nicholas Scarsdale, Emma V. Turtelboom, Dakotah Tyler, Judah Van Zandt, and Edward W. Schwieterman
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Exoplanets ,Radial velocity ,Mini Neptunes ,Astronomy ,QB1-991 - Abstract
Exoplanet discoveries have revealed a dramatic diversity of planet sizes across a vast array of orbital architectures. Sub-Neptunes are of particular interest; due to their absence in our own solar system, we rely on demographics of exoplanets to better understand their bulk composition and formation scenarios. Here, we present the discovery and characterization of TOI-1437 b, a sub-Neptune with a 18.84 day orbit around a near-solar analog ( M _⋆ = 1.10 ± 0.10 M _☉ , R _⋆ =1.17 ± 0.12 R _☉ ). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite (TESS) mission and radial velocity (RV) follow-up observations were carried out as a part of the TESS-Keck Survey using both the HIRES instrument at Keck Observatory and the Levy Spectrograph on the Automated Planet Finder telescope. A combined analysis of these data reveal a planet radius of R _p = 2.24 ± 0.23 R _⊕ and a mass measurement of M _p = 9.6 ± 3.9 M _⊕ ). TOI-1437 b is one of few (∼50) known transiting sub-Neptunes orbiting a solar-mass star that has a RV mass measurement. As the formation pathway of these worlds remains an unanswered question, the precise mass characterization of TOI-1437 b may provide further insight into this class of planet.
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- 2024
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19. TESS Giants Transiting Giants. VI. Newly Discovered Hot Jupiters Provide Evidence for Efficient Obliquity Damping after the Main Sequence
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Nicholas Saunders, Samuel K. Grunblatt, Ashley Chontos, Fei Dai, Daniel Huber, Jingwen Zhang, Guđmundur Stefánsson, Jennifer L. van Saders, Joshua N. Winn, Daniel Hey, Andrew W. Howard, Benjamin Fulton, Howard Isaacson, Corey Beard, Steven Giacalone, Judah Van Zandt, Joseph M. Akana Murphey, Malena Rice, Sarah Blunt, Emma Turtelboom, Paul A. Dalba, Jack Lubin, Casey Brinkman, Emma M. Louden, Emma Page, Cristilyn N. Watkins, Karen A. Collins, Chris Stockdale, Thiam-Guan Tan, Richard P. Schwarz, Bob Massey, Steve B. Howell, Andrew Vanderburg, George R. Ricker, Jon M. Jenkins, Sara Seager, Jessie L. Christiansen, Tansu Daylan, Ben Falk, Max Brodheim, Steven R. Gibson, Grant M. Hill, Bradford Holden, Aaron Householder, Stephen Kaye, Russ R. Laher, Kyle Lanclos, Erik A. Petigura, Arpita Roy, Ryan A. Rubenzahl, Christian Schwab, Abby P. Shaum, Martin M. Sirk, Christopher L. Smith, Josh Walawender, and Sherry Yeh
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Exoplanet astronomy ,Exoplanet dynamics ,Exoplanet detection methods ,Exoplanet evolution ,Exoplanet migration ,Exoplanets ,Astronomy ,QB1-991 - Abstract
The degree of alignment between a star’s spin axis and the orbital plane of its planets (the stellar obliquity) is related to interesting and poorly understood processes that occur during planet formation and evolution. Hot Jupiters orbiting hot stars (≳6250 K) display a wide range of obliquities, while similar planets orbiting cool stars are preferentially aligned. Tidal dissipation is expected to be more rapid in stars with thick convective envelopes, potentially explaining this trend. Evolved stars provide an opportunity to test the damping hypothesis, particularly stars that were hot on the main sequence and have since cooled and developed deep convective envelopes. We present the first systematic study of the obliquities of hot Jupiters orbiting subgiants that recently developed convective envelopes using Rossiter–McLaughlin observations. Our sample includes two newly discovered systems in the Giants Transiting Giants survey (TOI-6029 b, TOI-4379 b). We find that the orbits of hot Jupiters orbiting subgiants that have cooled below ∼6250 K are aligned or nearly aligned with the spin axis of their host stars, indicating rapid tidal realignment after the emergence of a stellar convective envelope. We place an upper limit for the timescale of realignment for hot Jupiters orbiting subgiants at ∼500 Myr. Comparison with a simplified tidal evolution model shows that obliquity damping needs to be ∼4 orders of magnitude more efficient than orbital period decay to damp the obliquity without destroying the planet, which is consistent with recent predictions for tidal dissipation from inertial waves excited by hot Jupiters on misaligned orbits.
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- 2024
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20. Migration and Evolution of giant ExoPlanets (MEEP). I. Nine Newly Confirmed Hot Jupiters from the TESS Mission
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Jack Schulte, Joseph E. Rodriguez, Allyson Bieryla, Samuel N. Quinn, Karen A. Collins, Samuel W. Yee, Andrew C. Nine, Melinda Soares-Furtado, David W. Latham, Jason D. Eastman, Khalid Barkaoui, David R. Ciardi, Diana Dragomir, Mark E. Everett, Steven Giacalone, Ismael Mireles, Felipe Murgas, Norio Narita, Avi Shporer, Ivan A. Strakhov, Stephanie Striegel, Martin Vaňko, Noah Vowell, Gavin Wang, Carl Ziegler, Michael Bellaver, Paul Benni, Serge Bergeron, Henri M. J. Boffin, César Briceño, Catherine A. Clark, Kevin I. Collins, Jerome P. de Leon, Courtney D. Dressing, Phil Evans, Emma Esparza-Borges, Jeremy Fedewa, Akihiko Fukui, Tianjun Gan, Ivan S. Gerasimov, Joel D. Hartman, Holden Gill, Michaël Gillon, Keith Horne, Ferran Grau Horta, Steve B. Howell, Keisuke Isogai, Emmanuël Jehin, Jon M. Jenkins, Raine Karjalainen, John F. Kielkopf, Kathryn V. Lester, Colin Littlefield, Michael B. Lund, Andrew W. Mann, Mason McCormack, Edward J. Michaels, Shane Painter, Enric Palle, Hannu Parviainen, David-Michael Peterson, Francisco J. Pozuelos, Zachary Raup, Phillip Reed, Howard M. Relles, George R. Ricker, Arjun B. Savel, Richard P. Schwarz, S. Seager, Ramotholo Sefako, Gregor Srdoc, Chris Stockdale, Hannah Sullivan, Mathilde Timmermans, and Joshua N. Winn
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Exoplanet astronomy ,Exoplanet migration ,Exoplanet detection methods ,Exoplanets ,Transits ,Radial velocity ,Astronomy ,QB1-991 - Abstract
Hot Jupiters were many of the first exoplanets discovered in the 1990s, but in the decades since their discovery the mysteries surrounding their origins have remained. Here we present nine new hot Jupiters (TOI-1855 b, TOI-2107 b, TOI-2368 b, TOI-3321 b, TOI-3894 b, TOI-3919 b, TOI-4153 b, TOI-5232 b, and TOI-5301 b) discovered by NASA’s TESS mission and confirmed using ground-based imaging and spectroscopy. These discoveries are the first in a series of papers named the Migration and Evolution of giant ExoPlanets survey and are part of an ongoing effort to build a complete sample of hot Jupiters orbiting FGK stars, with a limiting Gaia G -band magnitude of 12.5. This effort aims to use homogeneous detection and analysis techniques to generate a set of precisely measured stellar and planetary properties that is ripe for statistical analysis. The nine planets presented in this work occupy a range of masses (0.55 M _J < M _P < 3.88 M _J ) and sizes (0.967 R _J < R _P < 1.438 R _J ) and orbit stars that have an effective temperature in the range of 5360 K < T _eff < 6860 K with Gaia G -band magnitudes ranging from 11.1 to 12.7. Two of the planets in our sample have detectable orbital eccentricity: TOI-3919 b ( $e={0.259}_{-0.036}^{+0.033}$ ) and TOI-5301 b ( $e={0.33}_{-0.10}^{+0.11}$ ). These eccentric planets join a growing sample of eccentric hot Jupiters that are consistent with high-eccentricity tidal migration, one of the three most prominent theories explaining hot Jupiter formation and evolution.
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- 2024
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21. The SN 2023ixf Progenitor in M101. II. Properties
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Schuyler D. Van Dyk, Sundar Srinivasan, Jennifer E. Andrews, Monika Soraisam, Tamás Szalai, Steve B. Howell, Howard Isaacson, Thomas Matheson, Erik Petigura, Peter Scicluna, Andrew W. Stephens, Judah Van Zandt, WeiKang Zheng, Sang-Hyun Chun, and Alexei V. Fillippenko
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Type II supernovae ,Massive stars ,Late-type stars ,M supergiant stars ,Stellar evolution ,Astrophysics ,QB460-466 - Abstract
We follow our first paper with an analysis of the ensemble of the extensive preexplosion ground- and space-based infrared observations of the red supergiant (RSG) progenitor candidate for the nearby core-collapse supernova SN 2023ixf in Messier 101, together with optical data prior to the explosion obtained with the Hubble Space Telescope (HST). We have confirmed the association of the progenitor candidate with the supernova (SN), as well as constrained the metallicity at the SN site, based on SN observations with instruments at Gemini-North. The internal host extinction to the SN has also been confirmed from a high-resolution Keck spectrum. We fit the observed spectral energy distribution (SED) for the star, accounting for its intrinsic variability, with dust radiative-transfer modeling, which assumes a silicate-rich dust shell ahead of the underlying stellar photosphere. The star is heavily dust obscured, likely the dustiest progenitor candidate yet encountered. We found median estimates of the star’s effective temperature and luminosity of 2770 K and 9.0 × 10 ^4 L _⊙ , with 68% credible intervals of 2340–3150 K and (7.5–10.9) × 10 ^4 L _⊙ , respectively. The candidate may have a Galactic RSG analog, IRC −10414, with a strikingly similar SED and luminosity. Via comparison with single-star evolutionary models we have constrained the initial mass of the progenitor candidate from 12 M _⊙ to as high as 14 M _⊙ . We have had available to us an extraordinary view of the SN 2023ixf progenitor candidate, which should be further followed up in future years with HST and the James Webb Space Telescope.
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- 2024
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22. The Discovery and Follow-up of Four Transiting Short-period Sub-Neptunes Orbiting M Dwarfs
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Yasunori Hori, Akihiko Fukui, Teruyuki Hirano, Norio Narita, Jerome P. de Leon, Hiroyuki Tako Ishikawa, Joel D. Hartman, Giuseppe Morello, Nestor Abreu García, Leticia Álvarez Hernández, Víctor J. S. Béjar, Yéssica Calatayud-Borras, Ilaria Carleo, Gareb Enoc, Emma Esparza-Borges, Izuru Fukuda, Daniel Galán, Samuel Geraldía-González, Yuya Hayashi, Masahiro Ikoma, Kai Ikuta, Keisuke Isogai, Taiki Kagetani, Yugo Kawai, Kiyoe Kawauchi, Tadahiro Kimura, Takanori Kodama, Judith Korth, Nobuhiko Kusakabe, Andrés Laza-Ramos, John H. Livingston, Rafael Luque, Kohei Miyakawa, Mayuko Mori, Felipe Murgas, Jaume Orell-Miquel, Enric Palle, Hannu Parviainen, Alberto Peláez-Torres, Marta Puig-Subirà, Manuel Sánchez-Benavente, Paula Sosa-Guillén, Monika Stangret, Yuka Terada, Sara Muñoz Torres, Noriharu Watanabe, Gaspar Á. Bakos, Khalid Barkaoui, Charles Beichman, Zouhair Benkhaldoun, Andrew W. Boyle, David R. Ciardi, Catherine A. Clark, Karen A. Collins, Kevin I. Collins, Dennis M. Conti, Ian J.M. Crossfield, Mark E. Everett, Elise Furlan, Mourad Ghachoui, Michaël Gillon, Erica J. Gonzales, Jesus Higuera, Keith Horne, Steve B. Howell, Emmanuël Jehin, Kathryn V. Lester, Michael B. Lund, Rachel Matson, Elisabeth C. Matthews, Francisco J. Pozuelos, Boris S. Safonov, Joshua E. Schlieder, Richard P. Schwarz, Ramotholo Sefako, Gregor Srdoc, Ivan A. Strakhov, Mathilde Timmermans, William C. Waalkes, Carl Ziegler, David Charbonneau, Zahra Essack, Natalia M. Guerrero, Hiroki Harakawa, Christina Hedges, Masato Ishizuka, Jon M. Jenkins, Mihoko Konishi, Takayuki Kotani, Tomoyuki Kudo, Takashi Kurokawa, Masayuki Kuzuhara, Jun Nishikawa, Masashi Omiya, George R. Ricker, Sara Seager, Takuma Serizawa, Stephanie Striegel, Motohide Tamura, Akitoshi Ueda, Roland Vanderspek, Sébastien Vievard, and Joshua N. Winn
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Exoplanets ,Mini Neptunes ,Radial velocity ,Transit photometry ,Tides ,M dwarf stars ,Astronomy ,QB1-991 - Abstract
Sub-Neptunes with radii of 2–3 R _⊕ are intermediate in size between rocky planets and Neptune-sized planets. The orbital properties and bulk compositions of transiting sub-Neptunes provide clues to the formation and evolution of close-in small planets. In this paper, we present the discovery and follow-up of four sub-Neptunes orbiting M dwarfs (TOI-782, TOI-1448, TOI-2120, and TOI-2406), three of which were newly validated by ground-based follow-up observations and statistical analyses. TOI-782 b, TOI-1448 b, TOI-2120 b, and TOI-2406 b have radii of ${R}_{{\rm{p}}}={2.740}_{-0.079}^{+0.082}\,{R}_{\oplus }$ , ${2.769}_{-0.068}^{+0.073}\,{R}_{\oplus }$ , 2.120 ± 0.067 R _⊕ , and ${2.830}_{-0.066}^{+0.068}\,{R}_{\oplus }$ and orbital periods of P = 8.02, 8.11, 5.80, and 3.08 days, respectively. Doppler monitoring with the Subaru/InfraRed Doppler instrument led to 2 σ upper limits on the masses of
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- 2024
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23. GJ 238 b: A 0.57 Earth Radius Planet Orbiting an M2.5 Dwarf Star at 15.2 pc
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Evan Tey, Avi Shporer, Zifan Lin, Keivan G. Stassun, Jack J. Lissauer, Coel Hellier, Karen A. Collins, Kevin I. Collins, Geof Wingham, Howard M. Relles, Franco Mallia, Giovanni Isopi, John F. Kielkopf, Dennis M. Conti, Richard P. Schwarz, Aldo Zapparata, Steven Giacalone, Elise Furlan, Zachary D. Hartman, Steve B. Howell, Nicholas J. Scott, Carl Ziegler, César Briceño, Nicholas Law, Andrew W. Mann, David Charbonneau, Zahra Essack, Stephanie Striegel, George R. Ricker, Roland Vanderspek, Sara Seager, Joshua N. Winn, and Jon M. Jenkins
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Exoplanets ,Exoplanet detection methods ,Transit photometry ,Astronomy ,QB1-991 - Abstract
We report the discovery of the transiting planet GJ 238 b, with a radius of 0.566 ± 0.014 R _⊕ (1.064 ± 0.026 times the radius of Mars) and an orbital period of 1.74 days. The transit signal was detected by the TESS mission and designated TOI-486.01. The star’s position close to the southern ecliptic pole allows for almost continuous observations by TESS when it is observing the southern sky. The host star is an M2.5 dwarf with V = 11.57 ± 0.02 mag, K = 7.030 ± 0.023 mag, a distance of 15.2156 ± 0.0030 pc, a mass of ${0.4193}_{-0.0098}^{+0.0095}$ M _☉ , a radius of ${0.4314}_{-0.0071}^{+0.0075}$ R _☉ , and an effective temperature of 3485 ± 140 K. We validate the planet candidate by ruling out or rendering highly unlikely each of the false positive scenarios, based on archival data and ground-based follow-up observations. Validation was facilitated by the host star’s small size and high proper motion of 892.633 ± 0.025 mas yr ^–1 .
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- 2024
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24. The TESS-Keck Survey. XX. 15 New TESS Planets and a Uniform RV Analysis of All Survey Targets
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Alex S. Polanski, Jack Lubin, Corey Beard, Joseph M. Akana Murphy, Ryan Rubenzahl, Michelle L. Hill, Ian J. M. Crossfield, Ashley Chontos, Paul Robertson, Howard Isaacson, Stephen R. Kane, David R. Ciardi, Natalie M. Batalha, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Erik A. Petigura, Lauren M. Weiss, Isabel Angelo, Aida Behmard, Sarah Blunt, Casey L. Brinkman, Fei Dai, Paul A. Dalba, Tara Fetherolf, Steven Giacalone, Lea A. Hirsch, Rae Holcomb, Molly R. Kosiarek, Andrew W. Mayo, Mason G. MacDougall, Teo Močnik, Daria Pidhorodetska, Malena Rice, Lee J. Rosenthal, Nicholas Scarsdale, Emma V. Turtelboom, Dakotah Tyler, Judah Van Zandt, Samuel W. Yee, David R. Coria, Shannon D. Dulz, Joel D. Hartman, Aaron Householder, Sarah Lange, Andrew Langford, Emma M. Louden, Jared C. Siegel, Emily A. Gilbert, Erica J. Gonzales, Joshua E. Schlieder, Andrew W. Boyle, Jessie L. Christiansen, Catherine A. Clark, Rachel B. Fernandes, Michael B. Lund, Arjun B. Savel, Holden Gill, Charles Beichman, Rachel Matson, Elisabeth C. Matthews, E. Furlan, Steve B. Howell, Nicholas J. Scott, Mark E. Everett, John H. Livingston, Irina O. Ershova, Dmitry V. Cheryasov, Boris Safonov, Jorge Lillo-Box, David Barrado, and María Morales-Calderón
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Exoplanet astronomy ,Radial velocity ,Hot Jupiters ,Super Earths ,High resolution spectroscopy ,Catalogs ,Astrophysics ,QB460-466 - Abstract
The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number of confirmed planets from Kepler. Owing to differences in survey design, TESS continues to provide planets that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared to Kepler targets. In this work, we present the TESS-Keck Survey’s (TKS) Mass Catalog: a uniform analysis of all TKS RV survey data that has resulted in mass constraints for 126 planets and candidate signals. This includes 58 mass measurements that have reached ≥5 σ precision. We confirm or validate 32 new planets from the TESS mission either by significant mass measurement (15) or statistical validation (17), and we find no evidence of likely false positives among our entire sample. This work also serves as a data release for all previously unpublished TKS survey data, including 9,204 RV measurements and associated activity indicators over our three-year survey. We took the opportunity to assess the performance of our survey and found that we achieved many of our goals, including measuring the mass of 38 small (
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- 2024
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25. High-contrast, High-angular-resolution Optical Speckle Imaging: Uncovering Hidden Stellar Companions
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Steve B. Howell, Arturo O. Martinez, Douglas A. Hope, David R. Ciardi, Stuart M. Jefferies, Fabien R. Baron, and Michael B. Lund
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Speckle interferometry ,Astronomical instrumentation ,Binary stars ,Astronomy ,QB1-991 - Abstract
We explore the possibility of detecting very faint, very close-in stellar companions using large aperture ground-based telescopes and the technique of optical speckle imaging. We examine the state of high-angular-resolution speckle imaging and contrast levels being achieved using current speckle cameras on the Gemini 8 m telescope. We then explore the use of the modern image reconstruction technique—multiframe blind deconvolution (MFBD)—applied to speckle imaging from the Gemini 8 m telescope. We show that MFBD allows us to measure the flux ratio of the imaged stars to high accuracy and the reconstructed images yield higher precision astrometry. Both of these advances provide a large refinement in the derived astrophysical parameters compared with current Fourier techniques. MFBD image reconstructions reach contrast levels of ∼5 × 10 ^−3 , near the diffraction limit, to ∼10 ^−4 about 1.″0 away. At these deep contrast levels with angular limits starting near the 8 m diffraction limit (∼20 mas), most stellar companions to a solar-like stars can be imaged in the optical to near-IR bandpass (320–1000 nm). “To Xanadu we go...” —adapted from S. T. Coleridge.
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- 2024
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26. Planet Hunters TESS. V. A Planetary System Around a Binary Star, Including a Mini-Neptune in the Habitable Zone
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Nora L. Eisner, Samuel K. Grunblatt, Oscar Barragán, Thea H. Faridani, Chris Lintott, Suzanne Aigrain, Cole Johnston, Ian R. Mason, Keivan G. Stassun, Megan Bedell, Andrew W. Boyle, David R. Ciardi, Catherine A. Clark, Guillaume Hebrard, David W. Hogg, Steve B. Howell, Baptiste Klein, Joe Llama, Joshua N. Winn, Lily L. Zhao, Joseph M. Akana Murphy, Corey Beard, Casey L. Brinkman, Ashley Chontos, Pia Cortes-Zuleta, Xavier Delfosse, Steven Giacalone, Emily A. Gilbert, Neda Heidari, Rae Holcomb, Jon M. Jenkins, Flavien Kiefer, Jack Lubin, Eder Martioli, Alex S. Polanski, Nicholas Saunders, Sara Seager, Avi Shporer, Dakotah Tyler, Judah Van Zandt, Safaa Alhassan, Daval J. Amratlal, Lais I. Antonel, Simon L. S. Bentzen, Milton K. D Bosch, David Bundy, Itayi Chitsiga, Jérôme F. Delaunay, Xavier Doisy, Richard Ferstenou, Mark Fynø, James M. Geary, Gerry Haynaly, Pete Hermes, Marc Huten, Sam Lee, Paul Metcalfe, Garry J. Pennell, Joanna Puszkarska, Thomas Schäfer, Lisa Stiller, Christopher Tanner, Allan Tarr, and Andrew Wilkinson
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Exoplanet systems ,Exoplanet dynamics ,Transit photometry ,Binary stars ,Habitable zone ,Mini Neptunes ,Astronomy ,QB1-991 - Abstract
We report on the discovery and validation of a transiting long-period mini-Neptune orbiting a bright ( V = 9.0 mag) G dwarf (TOI 4633; R = 1.05 R _⊙ , M = 1.10 M _⊙ ). The planet was identified in data from the Transiting Exoplanet Survey Satellite by citizen scientists taking part in the Planet Hunters TESS project. Modelling of the transit events yields an orbital period of 271.9445 ± 0.0040 days and radius of 3.2 ± 0.20 R _⊕ . The Earth-like orbital period and an incident flux of ${1.56}_{-0.16}^{+0.20}$ F _⊕ places it in the optimistic habitable zone around the star. Doppler spectroscopy of the system allowed us to place an upper mass limit on the transiting planet and revealed a non-transiting planet candidate in the system with a period of 34.15 ± 0.15 days. Furthermore, the combination of archival data dating back to 1905 with new high angular resolution imaging revealed a stellar companion orbiting the primary star with an orbital period of around 230 yr and an eccentricity of about 0.9. The long period of the transiting planet, combined with the high eccentricity and close approach of the companion star makes this a valuable system for testing the formation and stability of planets in binary systems.
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- 2024
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27. Identification of the Top TESS Objects of Interest for Atmospheric Characterization of Transiting Exoplanets with JWST
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Benjamin J. Hord, Eliza M.-R. Kempton, Thomas M. Evans-Soma, David W. Latham, David R. Ciardi, Diana Dragomir, Knicole D. Colón, Gabrielle Ross, Andrew Vanderburg, Zoe L. de Beurs, Karen A. Collins, Cristilyn N. Watkins, Jacob Bean, Nicolas B. Cowan, Tansu Daylan, Caroline V. Morley, Jegug Ih, David Baker, Khalid Barkaoui, Natalie M. Batalha, Aida Behmard, Alexander Belinski, Zouhair Benkhaldoun, Paul Benni, Krzysztof Bernacki, Allyson Bieryla, Avraham Binnenfeld, Pau Bosch-Cabot, François Bouchy, Valerio Bozza, Rafael Brahm, Lars A. Buchhave, Michael Calkins, Ashley Chontos, Catherine A. Clark, Ryan Cloutier, Marion Cointepas, Kevin I. Collins, Dennis M. Conti, Ian J. M. Crossfield, Fei Dai, Jerome P. de Leon, Georgina Dransfield, Courtney Dressing, Adam Dustor, Gilbert Esquerdo, Phil Evans, Sergio B. Fajardo-Acosta, Jerzy Fiołka, Raquel Forés-Toribio, Antonio Frasca, Akihiko Fukui, Benjamin Fulton, Elise Furlan, Tianjun Gan, Davide Gandolfi, Mourad Ghachoui, Steven Giacalone, Emily A. Gilbert, Michaël Gillon, Eric Girardin, Erica Gonzales, Ferran Grau Horta, Joao Gregorio, Michael Greklek-McKeon, Pere Guerra, J. D. Hartman, Coel Hellier, Ian Helm, Krzysztof G. Hełminiak, Thomas Henning, Michelle L. Hill, Keith Horne, Andrew W. Howard, Steve B. Howell, Daniel Huber, Giovanni Isopi, Emmanuel Jehin, Jon M. Jenkins, Eric L. N. Jensen, Marshall C. Johnson, Andrés Jordán, Stephen R. Kane, John F. Kielkopf, Vadim Krushinsky, Sławomir Lasota, Elena Lee, Pablo Lewin, John H. Livingston, Jack Lubin, Michael B. Lund, Franco Mallia, Christopher R. Mann, Giuseppi Marino, Nataliia Maslennikova, Bob Massey, Rachel Matson, Elisabeth Matthews, Andrew W. Mayo, Tsevi Mazeh, Kim K. McLeod, Edward J. Michaels, Teo Močnik, Mayuko Mori, Georgia Mraz, Jose A. Muñoz, Norio Narita, Krupa Natarajan, Louise Dyregaard Nielsen, Hugh Osborn, Enric Palle, Aviad Panahi, Riccardo Papini, Peter Plavchan, Alex S. Polanski, Adam Popowicz, Francisco J. Pozuelos, Samuel N. Quinn, Don J. Radford, Phillip A. Reed, Howard M. Relles, Malena Rice, Paul Robertson, Joseph E. Rodriguez, Lee J. Rosenthal, Ryan A. Rubenzahl, Nicole Schanche, Joshua Schlieder, Richard P. Schwarz, Ramotholo Sefako, Avi Shporer, Alessandro Sozzetti, Gregor Srdoc, Chris Stockdale, Alexander Tarasenkov, Thiam-Guan Tan, Mathilde Timmermans, Eric B. Ting, Judah Van Zandt, JP Vignes, Ian Waite, Noriharu Watanabe, Lauren M. Weiss, Justin Wittrock, George Zhou, Carl Ziegler, and Shay Zucker
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Exoplanet astronomy ,Exoplanet atmospheres ,Transit photometry ,James Webb Space Telescope ,Exoplanets ,Astronomy ,QB1-991 - Abstract
JWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5000 confirmed planets, more than 4000 Transiting Exoplanet Survey Satellite (TESS) planet candidates are still unconfirmed and many of the best planets for atmospheric characterization may remain to be identified. We present a sample of TESS planets and planet candidates that we identify as “best-in-class” for transmission and emission spectroscopy with JWST. These targets are sorted into bins across equilibrium temperature T _eq and planetary radius R _p and are ranked by a transmission and an emission spectroscopy metric (TSM and ESM, respectively) within each bin. We perform cuts for expected signal size and stellar brightness to remove suboptimal targets for JWST. Of the 194 targets in the resulting sample, 103 are unconfirmed TESS planet candidates, also known as TESS Objects of Interest (TOIs). We perform vetting and statistical validation analyses on these 103 targets to determine which are likely planets and which are likely false positives, incorporating ground-based follow-up from the TESS Follow-up Observation Program to aid the vetting and validation process. We statistically validate 18 TOIs, marginally validate 31 TOIs to varying levels of confidence, deem 29 TOIs likely false positives, and leave the dispositions for four TOIs as inconclusive. Twenty-one of the 103 TOIs were confirmed independently over the course of our analysis. We intend for this work to serve as a community resource and motivate formal confirmation and mass measurements of each validated planet. We encourage more detailed analysis of individual targets by the community.
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- 2024
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28. Limits on Optical Counterparts to the Repeating Fast Radio Burst 20180916B from High-speed Imaging with Gemini-North/‘Alopeke
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Charles D. Kilpatrick, Nicolas Tejos, Bridget C. Andersen, J. Xavier Prochaska, Consuelo Núñez, Emmanuel Fonseca, Zachary Hartman, Steve B. Howell, Tom Seccull, and Shriharsh P. Tendulkar
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Magnetars ,Radio bursts ,Pulsars ,Astrophysics ,QB460-466 - Abstract
We report on contemporaneous optical observations at ≈10 ms timescales from the fast radio burst (FRB) 20180916B of two repeat bursts (FRB 20201023 and FRB 20220908) taken with the ‘Alopeke camera on the Gemini-North telescope. These repeats have radio fluences of 2.8 and 3.5 Jy ms, respectively, approximately in the lower 50th percentile for fluence from this repeating burst. The ‘Alopeke data reveal no significant optical detections at the FRB position and we place 3 σ upper limits to the optical fluences of
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- 2024
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29. Revised Architecture and Two New Super-Earths in the HD 134606 Planetary System
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Zhexing Li, Stephen R. Kane, Timothy D. Brandt, Tara Fetherolf, Paul Robertson, Jinglin Zhao, Paul A. Dalba, Robert A. Wittenmyer, R. Paul Butler, Matías R. Díaz, Steve B. Howell, Jeremy Bailey, Brad Carter, Elise Furlan, Crystal L. Gnilka, Jonathan Horner, Hugh R. A. Jones, Simon O’Toole, and Chris Tinney
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Exoplanets ,Exoplanet detection methods ,Exoplanet dynamics ,Exoplanet systems ,Radial velocity ,Photometry ,Astronomy ,QB1-991 - Abstract
Multiplanet systems exhibit a diversity of architectures that diverge from the solar system and contribute to the topic of exoplanet demographics. Radial velocity (RV) surveys form a crucial component of exoplanet surveys, as their long observational baselines allow for searches for more distant planetary orbits. This work provides a significantly revised architecture for the multiplanet system HD 134606 using both HARPS and UCLES RVs. We confirm the presence of previously reported planets b, c, and d with periods of ${12.0897}_{-0.0018}^{+0.0019}$ , ${58.947}_{-0.054}^{+0.056}$ , and ${958.7}_{-5.9}^{+6.3}$ days and masses of ${9.14}_{-0.63}^{+0.65}$ , 11.0 ± 1, and 44.5 ± 2.9 Earth masses, respectively, with the planet d orbit significantly revised to over double that originally reported. We report two newly detected super-Earths, e and f, with periods of ${4.31943}_{-0.00068}^{+0.00075}$ and ${26.9}_{-0.017}^{+0.019}$ days and masses of ${2.31}_{-0.35}^{+0.36}$ and ${5.52}_{-0.73}^{+0.74}$ Earth masses, respectively. In addition, we identify a linear trend in the RV time series, and the cause of this acceleration is deemed to be a newly detected massive companion with a very long orbital period. HD 134606 now displays four low-mass planets in a compact region near the star, one gas giant further out in the habitable zone, an additional companion in the outer regime, and a low-mass M dwarf stellar companion at large separation, making it an intriguing target for system formation/evolution studies. The location of planet d in the habitable zone proves to be an exciting candidate for future space-based direct imaging missions, whereas continued RV observations of this system are recommended for understanding the nature of the massive, long-period companion.
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- 2024
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30. Circumstellar Disk Accretion Across the Lagoon Nebula: The Influence of Environment and Stellar Mass
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Laura Venuti, Ann Marie Cody, Giacomo Beccari, Luisa M. Rebull, Michael J. Irwin, Apoorva Thanvantri, Sowmya Thanvantri, Silvia H. P. Alencar, Clara O. Leal, Geert Barentsen, Janet E. Drew, and Steve B. Howell
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Stellar accretion disks ,Young stellar objects ,Star forming regions ,T Tauri stars ,Herbig Ae/Be stars ,Variable stars ,Astronomy ,QB1-991 - Abstract
Pre-main-sequence disk accretion is pivotal for determining the final stellar properties and the early conditions for close-in planets. We aim to establish the impact of internal (stellar mass) and external (radiation field) parameters on the disk evolution in the Lagoon Nebula massive star-forming region. We employ simultaneous u , g , r , i , H α time-series photometry, archival infrared data, and high-precision K2 light curves to derive the stellar, disk, and accretion properties for 1012 Lagoon Nebula members. We estimate that of all young stars in the Lagoon Nebula, 34%–37% have inner disks traceable down to ∼12 μ m, while 38%–41% are actively accreting. We detect disks ∼1.5 times more frequently around G, K, and M stars than around higher-mass stars, which appear to deplete their inner disks on shorter timescales. We find tentative evidence for a faster disk evolution in the central regions of the Lagoon Nebula, where the bulk of the O/B population is located. Conversely, disks appear to last longer at the nebula outskirts, where the measured fraction of disk-bearing stars tends to exceed that of accreting and disk-free stars. The derived mass accretion rates show a nonuniform dependence on stellar mass between ∼0.2 and 5 M _⊙ . In addition, the typical accretion rates appear to differ across the Lagoon Nebula extension, with values twice lower in the core region than at its periphery. Finally, we detect tentative radial density gradients in the surface accretion shocks, leading to lags in the appearance of light curve brightness features as a function of wavelength that can amount to ∼7%–30% of the rotation period.
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- 2024
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31. High-resolution Imaging of a TESS Control Sample: Verifying a Deficit of Close-in Stellar Companions to Exoplanet Host Stars
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Colin Littlefield, Steve B. Howell, David R. Ciardi, Kathryn V. Lester, Mark E. Everett, Elise Furlan, Rachel A. Matson, Sergio B. Fajardo-Acosta, and Crystal L. Gnilka
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Speckle interferometry ,Exoplanet astronomy ,Astronomy ,QB1-991 - Abstract
The large number of exoplanets discovered with the Transiting Exoplanet Survey Satellite (TESS) means that any observational biases from TESS could influence the derived stellar multiplicity statistics of exoplanet host stars. To investigate this problem, we obtained speckle interferometry of 207 control stars whose properties in the TESS Input Catalog (TIC) closely match those of an exoplanetary host star in the TESS Object of Interest (TOI) catalog, with the objective of measuring the fraction of these stars that have companions within ∼1.″2. Our main result is the identification of a bias in the creation of the control sample that prevents the selection of binaries with 0.″1 ≲ ρ ≲ 1.″2 and Δmag ≲3. This bias is the result of large astrometric residuals that cause binaries with these parameters to fail the quality checks used to create the TIC, which in turn causes them to have incomplete stellar parameters (and uncertainties) in the TIC. Any stellar multiplicity study that relies exclusively upon TIC stellar parameters to identify its targets will struggle to select unresolved binaries in this parameter space. Left uncorrected, this selection bias disproportionately excludes high-mass-ratio binaries, causing the mass-ratio distribution of the companions to deviate significantly from the uniform distribution expected of FGK-type field binaries. After accounting for this bias, the companion rate of the FGK control stars is consistent with the canonical 46% ± 2% rate from Raghavan et al., and the mass-ratio distribution agrees with that of binary TOI host stars. There is marginal evidence that the control-star companions have smaller projected orbital separations than TOI host stars from previous studies.
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- 2024
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32. Kepler K2Campaign 9 – II. First space-based discovery of an exoplanet using microlensing
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D Specht, R Poleski, M T Penny, E Kerins, I McDonald, Chung-Uk Lee, A Udalski, I A Bond, Y Shvartzvald, Weicheng Zang, R A Street, D W Hogg, B S Gaudi, T Barclay, G Barentsen, S B Howell, F Mullally, C B Henderson, S T Bryson, D A Caldwell, M R Haas, J E Van Cleve, K Larson, K McCalmont, C Peterson, D Putnam, S Ross, M Packard, L Reedy, Michael D Albrow, Sun-Ju Chung, Youn Kil Jung, Andrew Gould, Cheongho Han, Kyu-Ha Hwang, Yoon-Hyun Ryu, In-Gu Shin, Hongjing Yang, Jennifer C Yee, Sang-Mok Cha, Dong-Jin Kim, Seung-Lee Kim, Dong-Joo Lee, Yongseok Lee, Byeong-Gon Park, Richard W Pogge, M K Szymański, I Soszyński, K Ulaczyk, P Pietrukowicz, Sz Kozłowski, J Skowron, P Mróz, Shude Mao, Pascal Fouqué, Wei Zhu, F Abe, R Barry, D P Bennett, A Bhattacharya, A Fukui, H Fujii, Y Hirao, Y Itow, R Kirikawa, I Kondo, N Koshimoto, Y Matsubara, S Matsumoto, S Miyazaki, Y Muraki, G Olmschenk, C Ranc, A Okamura, N J Rattenbury, Y Satoh, T Sumi, D Suzuki, S I Silva, T Toda, P J Tristram, A Vandorou, H Yama, C Beichman, G Bryden, and S Calchi Novati
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- 2023
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33. V994 Herculis: a unique triply eclipsing sextuple star system
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P Zasche, T Borkovits, R Jayaraman, S A Rappaport, M Brož, D Vokrouhlický, I B Bíró, T Hegedüs, Z T Kiss, R Uhlař, H M Schwengeler, A Pál, M Mašek, S B Howell, S Dallaporta, U Munari, R Gagliano, T Jacobs, M H Kristiansen, D LaCourse, M Omohundro, I Terentev, A Vanderburg, Z Henzl, B P Powell, and V B Kostov
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- 2023
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34. Cranberry Proanthocyanidins Mitigate Reflux-Induced Transporter Dysregulation in an Esophageal Adenocarcinoma Model
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Yun Zhang, Katherine M. Weh, Bridget A. Tripp, Jennifer L. Clarke, Connor L. Howard, Shruthi Sunilkumar, Amy B. Howell, and Laura A. Kresty
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cancer prevention ,cranberry proanthocyanidins ,plant polyphenols ,reflux-induced esophageal adenocarcinoma ,ATP-binding cassette transporters ,solute carrier transporters ,Medicine ,Pharmacy and materia medica ,RS1-441 - Abstract
We recently reported that cranberry proanthocyanidins (C-PACs) inhibit esophageal adenocarcinoma (EAC) by 83% through reversing reflux-induced bacterial, inflammatory and immune-implicated proteins and genes as well as reducing esophageal bile acids, which drive EAC progression. This study investigated whether C-PACs’ mitigation of bile reflux-induced transporter dysregulation mechanistically contributes to EAC prevention. RNA was isolated from water-, C-PAC- and reflux-exposed rat esophagi with and without C-PAC treatment. Differential gene expression was determined by means of RNA sequencing and RT-PCR, followed by protein assessments. The literature, coupled with the publicly available Gene Expression Omnibus dataset GSE26886, was used to assess transporter expression levels in normal and EAC patient biopsies for translational relevance. Significant changes in ATP-binding cassette (ABC) transporters implicated in therapeutic resistance in humans (i.e., Abcb1, Abcb4, Abcc1, Abcc3, Abcc4, Abcc6 and Abcc10) and the transport of drugs, xenobiotics, lipids, and bile were altered in the reflux model with C-PACs’ mitigating changes. Additionally, C-PACs restored reflux-induced changes in solute carrier (SLC), aquaporin, proton and cation transporters (i.e., Slc2a1, Slc7a11, Slc9a1, Slco2a1 and Atp6v0c). This research supports the suggestion that transporters merit investigation not only for their roles in metabolism and therapeutic resistance, but as targets for cancer prevention and targeting preventive agents in combination with chemotherapeutics.
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- 2023
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35. Separated Twins or Just Siblings? A Multiplanet System around an M Dwarf Including a Cool Sub-Neptune
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Mallory Harris, Diana Dragomir, Ismael Mireles, Karen A. Collins, Solène Ulmer-Moll, Steve B. Howell, Keivan G. Stassun, George Zhou, Carl Ziegler, François Bouchy, César Briceño, David Charbonneau, Kevin I. Collins, Gábor Fűűrész, Natalia M. Guerrero, Jon M. Jenkins, Eric L. N. Jensen, Martti H. K. Kristiansen, Nicholas Law, Monika Lendl, Andrew W. Mann, Hugh P. Osborn, Samuel N. Quinn, George R. Ricker, Richard P. Schwarz, Sara Seager, Eric B. Ting, Roland Vanderspek, David Watanabe, and Joshua N. Winn
- Subjects
Exoplanet systems ,Exoplanet detection methods ,Exoplanet astronomy ,M dwarf stars ,Cold Neptunes ,Mini Neptunes ,Astrophysics ,QB460-466 - Abstract
We report the discovery of two TESS sub-Neptunes orbiting the early M dwarf TOI-904 (TIC 261257684). Both exoplanets, TOI-904 b and c, were initially observed in TESS Sector 12 with twin sizes of ${2.426}_{-0.157}^{+0.163}$ and ${2.167}_{-0.118}^{+0.130}$ R _⊕ , respectively. Through observations in five additional sectors in the TESS primary mission and the first and second extended missions, the orbital periods of the planets were measured to be 10.887 ± 0.001 and 83.999 ± 0.001 days, respectively. Reconnaissance radial velocity measurements (taken with EULER/CORALIE and SMARTS/CHIRON) and high-resolution speckle imaging with adaptive optics (obtained from SOAR/HRCAM and Gemini South/ZORRO) show no evidence of an eclipsing binary or a nearby companion, which, together with the low false-positive probabilities calculated with the statistical validation software TRICERATOPS, establishes the planetary nature of these candidates. The outer planet, TOI-904 c, is the longest-period M dwarf exoplanet found by TESS, with an estimated equilibrium temperature of 217 K. As the three other validated planets with comparable host stars and orbital periods were observed by Kepler around much dimmer stars ( J _mag > 12), TOI-904 c, orbiting a brighter star ( J _mag = 9.6), is the coldest M dwarf planet easily accessible for atmospheric follow-up. Future mass measurements and transmission spectroscopy of the similar-sized planets in this system could determine whether they are also similar in density and composition, suggesting a common formation pathway, or whether they have distinct origins.
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- 2023
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36. A pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 characterized with CHEOPS
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Thomas G Wilson, Elisa Goffo, Yann Alibert, Davide Gandolfi, Andrea Bonfanti, Carina M Persson, Andrew Collier Cameron, Malcolm Fridlund, Luca Fossati, Judith Korth, Willy Benz, Adrien Deline, Hans-Gustav Florén, Pascal Guterman, Vardan Adibekyan, Matthew J Hooton, Sergio Hoyer, Adrien Leleu, Alexander James Mustill, Sébastien Salmon, Sérgio G Sousa, Olga Suarez, Lyu Abe, Abdelkrim Agabi, Roi Alonso, Guillem Anglada, Joel Asquier, Tamas Bárczy, David Barrado Navascues, Susana C C Barros, Wolfgang Baumjohann, Mathias Beck, Thomas Beck, Nicolas Billot, Xavier Bonfils, Alexis Brandeker, Christopher Broeg, Edward M Bryant, Matthew R Burleigh, Marco Buttu, Juan Cabrera, Sébastien Charnoz, David R Ciardi, Ryan Cloutier, William D Cochran, Karen A Collins, Knicole D Colón, Nicolas Crouzet, Szilard Csizmadia, Melvyn B Davies, Magali Deleuil, Laetitia Delrez, Olivier Demangeon, Brice-Olivier Demory, Diana Dragomir, Georgina Dransfield, David Ehrenreich, Anders Erikson, Andrea Fortier, Tianjun Gan, Samuel Gill, Michaël Gillon, Crystal L Gnilka, Nolan Grieves, Sascha Grziwa, Manuel Güdel, Tristan Guillot, Jonas Haldemann, Kevin Heng, Keith Horne, Steve B Howell, Kate G Isaak, Jon M Jenkins, Eric L N Jensen, Laszlo Kiss, Gaia Lacedelli, Kristine Lam, Jacques Laskar, David W Latham, Alain Lecavelier des Etangs, Monika Lendl, Kathryn V Lester, Alan M Levine, John Livingston, Christophe Lovis, Rafael Luque, Demetrio Magrin, Wenceslas Marie-Sainte, Pierre F L Maxted, Andrew W Mayo, Brian McLean, Marko Mecina, Djamel Mékarnia, Valerio Nascimbeni, Louise D Nielsen, Göran Olofsson, Hugh P Osborn, Hannah L M Osborne, Roland Ottensamer, Isabella Pagano, Enric Pallé, Gisbert Peter, Giampaolo Piotto, Don Pollacco, Didier Queloz, Roberto Ragazzoni, Nicola Rando, Heike Rauer, Seth Redfield, Ignasi Ribas, George R Ricker, Martin Rieder, Nuno C Santos, Gaetano Scandariato, François-Xavier Schmider, Richard P Schwarz, Nicholas J Scott, Sara Seager, Damien Ségransan, Luisa Maria Serrano, Attila E Simon, Alexis M S Smith, Manfred Steller, Chris Stockdale, Gyula Szabó, Nicolas Thomas, Eric B Ting, Amaury H M J Triaud, Stéphane Udry, Vincent Van Eylen, Valérie Van Grootel, Roland K Vanderspek, Valentina Viotto, Nicholas Walton, and Joshua N Winn
- Published
- 2022
- Full Text
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37. Tentative Evidence for Water Vapor in the Atmosphere of the Neptune-sized Exoplanet HD106315c
- Author
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Laura Kreidberg, Paul Mollière, Ian J M Crossfield, Daniel P Thorngren, Yui Kawashima, Caroline V Morley, Björn Benneke, Thomas Mikal-Evans, David Berardo, Molly R Kosiarek, Varoujan Gorjian, David R Ciardi, Jessie L Christiansen, Diana Dragomir, Courtney D Dressing, Jonathan J Fortney, Benjamin J Fulton, Thomas P Greene, Kevin K Hardegree-Ullman, Andrew W Howard, Steve B Howell, Howard Isaacson, Jessica E Krick, John H Livingston, Joshua D Lothringer, Farisa Y Morales, Erik A Petigura, Joseph E Rodriguez, Joshua E Schlieder, and Lauren M Weiss
- Subjects
Astronomy - Abstract
We present a transmission spectrum for the Neptune-sized exoplanet HD 106315c from optical to infrared wavelengths based on transit observations from the Hubble Space Telescope/Wide Field Camera 3, K2, and Spitzer. The spectrum shows tentative evidence for a water absorption feature in the 1.1–1.7 μm wavelength range with a small amplitude of 30 ppm (corresponding to just 0.8 ± 0.04 atmospheric scale heights). Based on an atmospheric retrieval analysis, the presence of water vapor is tentatively favored with a Bayes factor of 1.7–2.6 (depending on prior assumptions). The spectrum is most consistent with either an enhanced metallicity or high-altitude condensates, or both. Cloud-free solar composition atmospheres are ruled out at >5σ confidence. We compare the spectrum to grids of cloudy and hazy forward models and find that the spectrum is fit well by models with moderate cloud lofting or haze formation efficiency over a wide range of metallicities (1–100× solar). We combine the constraints on the envelope composition with an interior structure model and estimate that the core mass fraction is ≳0.3. With a bulk composition reminiscent of that of Neptune and an orbital distance of 0.15 au, HD 106315c hints that planets may form out of broadly similar material and arrive at vastly different orbits later in their evolution.
- Published
- 2022
- Full Text
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38. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
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Ares Osborn, David J Armstrong, Bryson Cale, Rafael Brahm, Robert A Wittenmyer, Fei Dai, Ian J M Crossfield, Edward M Bryant, Vardan Adibekyan, Ryan Cloutier, Karen A Collins, E Delgado Mena, Malcolm Fridlund, Coel Hellier, Steve B Howell, George W King, Jorge Lillo-Box, Jon Otegi, S Sousa, Keivan G Stassun, Elisabeth C Matthews, Carl Ziegler, George Ricker, Roland Vanderspek, David W Latham, S Seager, Joshua N Winn, Jon M Jenkins, Jack S Acton, Brett C Addison, David R Anderson, Sarah Ballard, David Barrado, Susana C C Barros, Natalie Batalha, Daniel Bayliss, Thomas Barclay, Björn Benneke, John Berberian, Francois Bouchy, Brendan P Bowler, César Briceño, Christopher J Burke, Matthew R Burleigh, Sarah L Casewell, David Ciardi, Kevin I Collins, Benjamin F Cooke, Olivier D S Demangeon, Rodrigo F Díaz, C Dorn, Diana Dragomir, Courtney Dressing, Xavier Dumusque, Néstor Espinoza, P Figueira, Benjamin Fulton, E Furlan, E Gaidos, C Geneser, Samuel Gill, Michael R Goad, Erica J Gonzales, Varoujan Gorjian, Maximilian N Günther, Ravit Helled, Beth A Henderson, Thomas Henning, Aleisha Hogan, Saeed Hojjatpanah, Jonathan Horner, Andrew W Howard, Sergio Hoyer, Dan Huber, Howard Isaacson, James S Jenkins, Eric L N Jensen, Andrés Jordán, Stephen R Kane, Richard C Kidwell, John Kielkopf, Nicholas Law, Monika Lendl, M Lund, Rachel A Matson, Andrew W Mann, James McCormac, Matthew W Mengel, Farisa Y Morales, Louise D Nielsen, Jack Okumura, Hugh P Osborn, Erik A Petigura, Peter Plavchan, Don Pollacco, Elisa V Quintana, Liam Raynard, Paul Robertson, Mark E Rose, Arpita Roy, Michael Reefe, Alexandre Santerne, Nuno C Santos, Paula Sarkis, J Schlieder, Richard P Schwarz, Nicholas J Scott, Avi Shporer, A M S Smith, C Stibbard, Chris Stockdale, Paul A Strøm, Joseph D Twicken, Thiam-Guan Tan, A Tanner, J Teske, Rosanna H Tilbrook, C G Tinney, Stephane Udry, Jesus Noel Villaseñor, Jose I Vines, Sharon X Wang, Lauren M Weiss, Richard G West, Peter J Wheatley, Duncan J Wright, Hui Zhang, and F Zohrabi
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- 2021
- Full Text
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39. A speckle-imaging search for close triple companions of cataclysmic binaries
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Michael M Shara, Steve B Howell, Elise Furlan, Crystal L Gnilka, Anthony F J Moffat, Nicholas J Scott, and David Zurek
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- 2021
- Full Text
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40. HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS
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Tianjun Gan, Megan Bedell, Sharon Xuesong Wang, Daniel Foreman-Mackey, Jorge Meléndez, Shude Mao, Keivan G Stassun, Steve B Howell, Carl Ziegler, Robert A Wittenmyer, Coel Hellier, Karen A Collins, Avi Shporer, George R Ricker, Roland Vanderspek, David W Latham, Sara Seager, Joshua N Winn, Jon M Jenkins, Brett C Addison, Sarah Ballard, Thomas Barclay, Jacob L Bean, Brendan P Bowler, César Briceño, Ian J M Crossfield, Jason Dittman, Jonathan Horner, Eric L N Jensen, Stephen R Kane, John Kielkopf, Laura Kreidberg, Nicholas Law, Andrew W Mann, Matthew W Mengel, Edward H Morgan, Jack Okumura, Hugh P Osborn, Martin Paegert, Peter Plavchan, Richard P Schwarz, Bernie Shiao, Jeffrey C Smith, Lorenzo Spina, C G Tinney, Guillermo Torres, Joseph D Twicken, Michael Vezie, Gavin Wang, Duncan J Wright, and Hui Zhang
- Published
- 2021
- Full Text
- View/download PDF
41. TOI-712 A System of Adolescent Mini-Neptunes Extending to the Habitable Zone
- Author
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Sydney Vach, Samuel N Quinn, Andrew Vanderburg, Stephen R Kane, Karen A Collins, Adam L Kraus, George Zhou, Amber A Medina, Richard P Schwarz, Kevin I Collins, Dennis M Conti, Chris Stockdale, Bob Massey, Olga Suarez, Tristan Guillot, Djamel Mekarnia, Lyu Abe, Georgina Dransfield, Nicolas Crouzet, Amaury H M J Triaud, François-Xavier Schmider, Abelkrim Agabi, Marco Buttu, Coel Hellier, Elise Furlan, Crystal L Gnilka, Steve B Howell, Carl Ziegler, César Briceño, Nicholas Law, Andrew W Mann, Alexander A Rudat, Knicole D Colon, Mark E Rose, Michelle Kunimoto, Maximilian N Günther, David Charbonneau, David R Ciardi, George R Ricker, Roland K Vanderspek, David W Latham, Sara Seager, Joshua N Winn, and Jon M Jenkins
- Subjects
Astronomy - Abstract
As an all-sky survey, NASA’s Transiting Exoplanet Survey Satellite (TESS) mission is able to detect the brightest and rarest types of transiting planetary systems, including young planets that enable study of the evolutionary processes that occur within the first billion years. Here we report the discovery of a young, multiplanet system orbiting the bright K4.5V star, TOI-712 (V = 10.838, M* = 0.733+0.026-0.025 M⨀, R* = 0.674 ± 0.016 R⨀, Teff = 4622+61-60 K). From the TESS light curve, we measure a rotation period of 12.48 days and derive an age between about 500 Myr and 1.1 Gyr. The photometric observations reveal three transiting mini-Neptunes (Rb = 2.049+0.120-0.080 R⊕, Rc = 2.701+0.092-0.082 R⊕, Rd = 2.474+0.090-0.082 R⊕), with orbital periods of Pb = 9.531 days, Pc = 51.699 days, and Pd = 84.839 days. After modeling the three-planet system, an additional Earth-sized candidate is identified, TOI-712.05 (P = 4.32 days, RP = 0.81 ± 0.11 R⊕). We calculate that the habitable zone falls between 0.339 and 0.844 au (82.7 and 325.3 days), placing TOI-712 d near its inner edge. Among planetary systems harboring temperate planets, TOI-712 (T = 9.9) stands out as a relatively young star bright enough to motivate further characterization.
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- 2022
- Full Text
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42. HD 28109 Hosts A Trio of Transiting Neptunian Planets Including A Near-Resonant Pair, Confirmed By ASTEP From Antarctica
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Georgina Dransfield, Amaury H M J Triaud, Tristan Guillot, Djamel Mekarnia, David Nesvorny, Nicolas Crouzet, Lyu Abe, Karim Agabi, Marco Buttu, Juan Cabrera, Davide Gandolfi, Maximilian Gunther, Florian Rodler, Francois-Xavier Schmider, Philippe Stee, Olga Suarez, Karen A Collins, Martin Devora-Pajares, Steve B Howell, Elisabeth C Matthews, Matthew R Standing, Keivan G Stassun, Chris Stockdale, Samuel N Quinn, Carl Ziegler, Ian J M Crossfield, Jack J Lissauer, Andrew W Mann, Rachel Matson, Joshua Schlieder, and George Zhou
- Subjects
Astronomy - Abstract
We report on the discovery and characterization of three planets orbiting the F8 star HD 28109, which sits comfortably in TESS ’s continuous viewing zone. The two outer planets have periods of 56 . 0067 ±0 . 0003 d and 84 . 2597 + 0 . 0010 −0 . 0008 d, which implies a period ratio very close to that of the first-order 3:2 mean motion resonance, exciting transit timing variations (TTVs) of up to 60 min. These two planets were first identified by TESS , and we identified a third planet in the TESS photometry with a period of 22 . 8911 ±0 . 0004 d. We confirm the planetary nature of all three planetary candidates using ground-based photometry from Hazelwood , ASTEP , and LCO , including a full detection of the ∼9 h transit of HD 28109 c from Antarctica. The radii of the three planets are R b = 2 . 199 + 0 . 098 −0 . 10 R ⊕, R c = 4 . 23 ±0 . 11 R ⊕, and R d = 3 . 25 ±0 . 11 R ⊕; we characterize their masses using TTVs and precise radial velocities from ESPRESSO and HARPS, and find them to be M b = 18 . 5 + 9 . 1 −7 . 6 M ⊕, M c = 7 . 9 + 4 . 2 −3 . 0 M ⊕, and M d = 5 . 7 + 2 . 7 −2 . 1 M ⊕, making planet b a dense, massive planet while c and d are both underdense. We also demonstrate that the two outer planets are ripe for atmospheric characterization using transmission spectroscopy, especially given their position in the CVZ of James Webb Space Telescope . The data obtained to date are consistent with resonant (librating) and non-resonant (circulating) solutions; additional observations will show whether the pair is actually locked in resonance or just near-resonant.
- Published
- 2022
- Full Text
- View/download PDF
43. A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113
- Author
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H P Osborn, D J Armstrong, V Adibekyan, K A Collins, E Delgado-Mena, S B Howell, C Hellier, G W King, J Lillo-Box, L D Nielsen, J F Otegi, N C Santos, C Ziegler, D R Anderson, C Briceño, C Burke, D Bayliss, D Barrado, E M Bryant, D J A Brown, S C C Barros, F Bouchy, D A Caldwell, D M Conti, R F Díaz, D Dragomir, M Deleuil, O D S Demangeon, C Dorn, T Daylan, P Figueira, R Helled, S Hoyer, J M Jenkins, E L N Jensen, D W Latham, N Law, D R Louie, A W Mann, A Osborn, D L Pollacco, D R Rodriguez, B V Rackham, G Ricker, N J Scott, S G Sousa, S Seager, K G Stassun, J C Smith, P Strøm, S Udry, J Villaseñor, R Vanderspek, R West, P J Wheatley, and J N Winn
- Published
- 2021
- Full Text
- View/download PDF
44. Planet Hunters TESS IV: A Massive, Compact Hierarchical Triple Star System TIC 470710327
- Author
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N. L. Eisner, C. Johnston, S. Toonen, A. J. Frost, S. Janssens, C J Lintott, S Aigrain, H Sana, M Abdul-Masih, K Z Arellano-Córdova, P G Beck, E Bordier, E Cannon, A Escorza, M Fabry, L Hermansson, S B Howell, G Miller, S Sheyte, S Alhassan, E M L Baeten, F Barnet, S J Bean, M Bernau, D M Bundy, M Z Di Fraia, F M Emralino, B L Goodwin, P Hermes, T Hoffman, M Huten, R Janíček, S Lee, M T Mazzucato, D J Rogers, M P Rout, J Sejpka, C Tanner, I A Terentev, and D Urvoy
- Subjects
Astrophysics - Abstract
We report the discovery and analysis of a massive, compact, hierarchical triple system (TIC 470710327) initially identified by citizen scientists in data obtained by NASA’s Transiting Exoplanet Survey Satellite (TESS). Spectroscopic follow-up observations obtained with the HERMES spectrograph, combined with eclipse-timing variations (ETVs), confirm that the system is comprised of three OB stars, with a compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. Dynamical modelling of the system (from radial velocity and ETVs) reveal a rare configuration wherein the tertiary star (O9.5-B0.5V; 14–17 Mꙩ) is more massive than the combined mass of the inner binary (10.9–13.2 Mꙩ). Given the high mass of the tertiary, we predict that this system will undergo multiple phases of mass transfer in the future, and likely end up as a double neutron star gravitational wave progenitor or an exotic Thorne–Żytkow object. Further observational characterization of this system promises constraints on both formation scenarios of massive stars as well as their exotic evolutionary end-products.
- Published
- 2022
- Full Text
- View/download PDF
45. TOI-1075 b: A Dense, Massive, Ultra-short-period Hot Super-Earth Straddling the Radius Gap
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Zahra Essack, Avi Shporer, Jennifer A. Burt, Sara Seager, Saverio Cambioni, Zifan Lin, Karen A. Collins, Eric E. Mamajek, Keivan G. Stassun, George R. Ricker, Roland Vanderspek, David W. Latham, Joshua N. Winn, Jon M. Jenkins, R. Paul Butler, David Charbonneau, Kevin I. Collins, Jeffrey D. Crane, Tianjun Gan, Coel Hellier, Steve B. Howell, Jonathan Irwin, Andrew W. Mann, Ali Ramadhan, Stephen A. Shectman, Johanna K. Teske, Samuel W. Yee, Ismael Mireles, Elisa V. Quintana, Peter Tenenbaum, Guillermo Torres, and Elise Furlan
- Published
- 2023
- Full Text
- View/download PDF
46. Clinical evidence supporting cranberry as a complementary approach to Helicobacter pylori management
- Author
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Amy B. Howell
- Subjects
antibiotic resistance ,clinical trials ,Cranberry ,Helicobacter pylori ,stomach cancer ,suppression ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Abstract This concise review summarizes results of the latest clinical trials that support the use of standardized cranberry juice intake as a complementary means of suppressing Helicobacter pylori infections. While not a replacement for antibiotic therapies, this tolerable and accessible dietary approach to help reduce inoculum levels in high‐risk populations could help curb infections and potentially reduce antibiotic use and subsequent stomach cancer prevalence.
- Published
- 2020
- Full Text
- View/download PDF
47. Integrin alphaV modulates the cellular pharmacology of copper and cisplatin by regulating expression of the influx transporter CTR1
- Author
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Lin, Xinjian, Shang, Xiying, Manorek, Gerald, Fofana, Mariama, and B., Howell Stephen
- Subjects
Biochemistry and Cell Biology ,Biomedical and Clinical Sciences ,Biological Sciences ,Cancer ,Genetics ,Neurodegenerative ,1.1 Normal biological development and functioning ,Underpinning research ,Generic health relevance ,CTR1 ,Integrin αV ,Sp1 ,cellular pharmacology ,cisplatin ,copper - Abstract
The αV integrin is expressed in most cancer cells where it regulates a diverse array of cellular functions essential to the initiation, progression and metastasis of solid tumors. However, little is known about how αV integrin modulates cellular sensitivity to chemotherapeutic agents, particularly the platinum drugs. In this study, we found that down-regulation of αV sensitized human M21 cells to cisplatin (cDDP) through up-regulation of the copper influx transporter CTR1. Cells selected for low αV integrin expression (M21L) were more sensitive to cDDP, accompanied by increase in CTR1 mRNA and CTR1 protein levels, more intracellular cDDP accumulation and cDDP DNA adduct formation. Basal copper (Cu) content, Cu uptake, and Cu cytotoxicity were also increased. Transfection of a luciferase reporter construct containing the hCTR1 promoter sequence revealed an increase of the hCTR1 transcription activity in M21L cells. The basis for the increased hCTR1 transcription was related to an increase in the steady-state level of Sp1, a transcription factor known to drive hCTR1 expression. These results indicate that the αV integrin modulates sensitivity of human cells to the cytotoxic effect of cDDP by regulating expression of the Cu transporter CTR1, and introduce the concept that αV expression is linked to Cu homeostasis.
- Published
- 2014
48. Integrin αV modulates the cellular pharmacology of copper and cisplatin by regulating expression of the influx transporter CTR1.
- Author
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Lin, Xinjian, Shang, Xiying, Manorek, Gerald, Fofana, Mariama, and Stephen B, Howell
- Subjects
CTR1 ,Integrin αV ,Sp1 ,cellular pharmacology ,cisplatin ,copper ,Cancer ,Genetics ,Neurodegenerative ,1.1 Normal biological development and functioning ,Generic Health Relevance - Abstract
The αV integrin is expressed in most cancer cells where it regulates a diverse array of cellular functions essential to the initiation, progression and metastasis of solid tumors. However, little is known about how αV integrin modulates cellular sensitivity to chemotherapeutic agents, particularly the platinum drugs. In this study, we found that down-regulation of αV sensitized human M21 cells to cisplatin (cDDP) through up-regulation of the copper influx transporter CTR1. Cells selected for low αV integrin expression (M21L) were more sensitive to cDDP, accompanied by increase in CTR1 mRNA and CTR1 protein levels, more intracellular cDDP accumulation and cDDP DNA adduct formation. Basal copper (Cu) content, Cu uptake, and Cu cytotoxicity were also increased. Transfection of a luciferase reporter construct containing the hCTR1 promoter sequence revealed an increase of the hCTR1 transcription activity in M21L cells. The basis for the increased hCTR1 transcription was related to an increase in the steady-state level of Sp1, a transcription factor known to drive hCTR1 expression. These results indicate that the αV integrin modulates sensitivity of human cells to the cytotoxic effect of cDDP by regulating expression of the Cu transporter CTR1, and introduce the concept that αV expression is linked to Cu homeostasis.
- Published
- 2014
49. Epidemiology and etiology of infantile developmental and epileptic encephalopathies in Tasmania
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Tyson L. Ware, Shannon R. Huskins, Bronwyn E. Grinton, Yu‐Chi Liu, Mark F. Bennett, Michael Harvey, Jacinta McMahon, Danae Andreopoulos‐Malikotsinas, Melanie Bahlo, Katherine B. Howell, Michael S. Hildebrand, John A. Damiano, Alexander Rosenfeld, Mark T. Mackay, Simone Mandelstam, Richard J. Leventer, A. Simon Harvey, Jeremy L. Freeman, Ingrid E. Scheffer, Dean L. Jones, and Samuel F. Berkovic
- Subjects
developmental and epileptic encephalopathy ,incidence ,whole exome sequencing ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract We sought to determine incidence, etiologies, and yield of genetic testing in infantile onset developmental and epileptic encephalopathies (DEEs) in a population isolate, with an intensive multistage approach. Infants born in Tasmania between 2011 and 2016, with seizure onset
- Published
- 2019
- Full Text
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50. A Validated Pre-operative Risk Prediction Tool for Extended Inpatient Length of Stay Following Primary Total Hip or Knee Arthroplasty
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Daniel E. Goltz, Chelsea S. Sicat, Jay M. Levin, Joshua K. Helmkamp, Claire B. Howell, Daniel Waren, Cynthia L. Green, David Attarian, William A. Jiranek, Michael P. Bolognesi, Ran Schwarzkopf, and Thorsten M. Seyler
- Subjects
Orthopedics and Sports Medicine - Abstract
As value-based reimbursement models mature, understanding the potential trade-off between inpatient lengths of stay and complications or need for costly postacute care becomes more pressing. Understanding and predicting a patient's expected baseline length of stay may help providers understand how best to decide optimal discharge timing for high-risk total joint arthroplasty (TJA) patients.A retrospective review was conducted of 37,406 primary total hip (17,134, 46%) and knee (20,272, 54%) arthroplasties performed at two high-volume, geographically diverse, tertiary health systems during the study period. Patients were stratified by 3 binary outcomes for extended inpatient length of stay: 72 + hours (29%), 4 + days (11%), or 5 + days (5%). The predictive ability of over 50 sociodemographic/comorbidity variables was tested. Multivariable logistic regression models were created using institution #1 (derivation), with accuracy tested using the cohort from institution #2 (validation).During the study period, patients underwent an extended length of stay with a decreasing frequency over time, with privately insured patients having a significantly shorter length of stay relative to those with Medicare (1.9 versus 2.3 days, P.0001). Extended stay patients also had significantly higher 90-day readmission rates (P.0001), even when excluding those discharged to postacute care (P .01). Multivariable logistic regression models created from the training cohort demonstrated excellent accuracy (area under the curve (AUC): 0.755, 0.783, 0.810) and performed well under external validation (AUC: 0.719, 0.743, 0.763). Many important variables were common to all 3 models, including age, sex, American Society of Anesthesiologists (ASA) score, body mass index, marital status, bilateral case, insurance type, and 13 comorbidities.An online, freely available, preoperative clinical decision tool accurately predicts risk of extended inpatient length of stay after TJA. Many risk factors are potentially modifiable, and these validated tools may help guide clinicians in preoperative patient counseling, medical optimization, and understanding optimal discharge timing.
- Published
- 2023
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