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18 results on '"John Kielkopf"'

1. The K2 and TESS Synergy. III. Search and Rescue of the Lost Ephemeris for K2's First Planet

Author

Erica Thygesen, Joseph E. Rodriguez, Zoë L. de Beurs, Andrew Vanderburg, John H. Livingston, Jonathon Irwin, Alexander Venner, Michael Cretignier, Karen A. Collins, Allyson Bieryla, David Charbonneau, Ian J. M. Crossfield, Xavier Dumusque, John Kielkopf, David W. Latham, and Michael Werner

Subjects
Exoplanet astronomy, Exoplanet systems, Exoplanet catalogs, Exoplanets, Ephemerides, Transits, Astronomy, QB1-991
Abstract

K2-2 b/HIP 116454 b, the first exoplanet discovery by K2 during its Two-Wheeled Concept Engineering Test, is a sub-Neptune (2.5 ± 0.1 R _⊕ , 9.7 ± 1.2 M _⊕ ) orbiting a relatively bright ( K _S = 8.03) K-dwarf star on a 9.1 day period. Unfortunately, due to a spurious follow-up transit detection and ephemeris degradation, the transit ephemeris for this planet was lost. In this work, we recover and refine the transit ephemeris for K2-2 b, showing a ∼40 σ discrepancy from the discovery results. To accurately measure the transit ephemeris and update the parameters of the system, we jointly fit space-based photometric observations from NASA’s K2, Transiting Exoplanet Survey Satellite, and Spitzer missions with new photometric observations from the ground, as well as radial velocities from HARPS-N that are corrected for stellar activity using a new modeling technique. Ephemerides becoming lost or significantly degraded, as is the case for most transiting planets, highlights the importance of systematically updating transit ephemerides with upcoming large efforts expected to characterize hundreds of exoplanet atmospheres. K2-2 b sits at the high-mass peak of the known radius valley for sub-Neptunes, and is now well-suited for transmission spectroscopy with current and future facilities. Our updated transit ephemeris will ensure no more than a 13 minute uncertainty through 2030.

Published
2024
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2. TOI-1994b: A Low-mass Eccentric Brown Dwarf Transiting A Subgiant Star

Author

Emma Page, Joshua Pepper, Duncan Wright, Joseph E. Rodriguez, Robert A. Wittenmyer, Stephen R. Kane, Brett Addison, Timothy Bedding, Brendan P. Bowler, Thomas Barclay, Karen A. Collins, Phil Evans, Jonathan Horner, Eric L. N. Jensen, Marshall C. Johnson, John Kielkopf, Ismael Mireles, Peter Plavchan, Samuel N. Quinn, S. Seager, Avi Shporer, Keivan G. Stassun, Stephanie Striegel, Joshua N. Winn, George Zhou, and Carl Ziegler

Subjects
Brown dwarfs, Photometry, Radial velocity, Substellar companion stars, Astronomy, QB1-991
Abstract

We present the discovery of TOI-1994b, a low-mass brown dwarf transiting a hot subgiant star on a moderately eccentric orbit. TOI-1994 has an effective temperature of ${7700}_{-410}^{+720}$ K, V magnitude of 10.51 mag and log( g ) of ${3.982}_{-0.065}^{+0.067}$ . The brown dwarf has a mass of ${22.1}_{-2.5}^{+2.6}$ M _J , a period of 4.034 days, an eccentricity of ${0.341}_{-0.059}^{+0.054}$ , and a radius of ${1.220}_{-0.071}^{+0.082}$ R _J . TOI-1994b is more eccentric than other transiting brown dwarfs with similar masses and periods. The population of low-mass brown dwarfs may have properties similar to planetary systems if they were formed in the same way, but the short orbital period and high eccentricity of TOI-1994b may contrast this theory. An evolved host provides a valuable opportunity to understand the influence stellar evolution has on the substellar companion’s fundamental properties. With precise age, mass, and radius, the global analysis and characterization of TOI-1994b augments the small number of transiting brown dwarfs and allows the testing of substellar evolution models.

Published
2024
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3. TOI 560: Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS, and HIRES RVs

Author

Mohammed El Mufti, Peter P. Plavchan, Howard Isaacson, Bryson L. Cale, Dax L. Feliz, Michael A. Reefe, Coel Hellier, Keivan Stassun, Jason Eastman, Alex Polanski, Ian J. M. Crossfield, Eric Gaidos, Veselin Kostov, Justin M. Wittrock, Joel Villaseñor, Joshua E. Schlieder, Luke G. Bouma, Kevin I. Collins, Farzaneh Zohrabi, Rena A. Lee, Ahmad Sohani, John Berberian, David Vermilion, Patrick Newman, Claire Geneser, Angelle Tanner, Natalie M. Batalha, Courtney Dressing, Benjamin Fulton, Andrew W. Howard, Daniel Huber, Stephen R. Kane, Erik A. Petigura, Paul Robertson, Arpita Roy, Lauren M. Weiss, Aida Behmard, Corey Beard, Ashley Chontos, Fei Dai, Paul A. Dalba, Tara Fetherolf, Steven Giacalone, Michelle L. Hill, Lea A. Hirsch, Rae Holcomb, Jack Lubin, Andrew Mayo, Teo Močnik, Joseph M. Akana Murphy, Lee J. Rosenthal, Ryan A. Rubenzahl, Nicholas Scarsdale, Christopher Stockdale, Karen Collins, Ryan Cloutier, Howard Relles, Thiam-Guan Tan, Nicholas J Scott, Zach Hartman, Elisabeth Matthews, David R. Ciardi, Erica Gonzales, Rachel A. Matson, Charles Beichman, Allyson Bieryla, E. Furlan, Crystal L. Gnilka, Steve B. Howell, Carl Ziegler, César Briceño, Nicholas Law, Andrew W. Mann, Markus Rabus, Marshall C. Johnson, Jessie Christiansen, Laura Kreidberg, David Anthony Berardo, Drake Deming, Varoujan Gorjian, Farisa Y. Morales, Björn Benneke, Diana Dragomir, Robert A. Wittenmyer, Sarah Ballard, Brendan P. Bowler, Jonathan Horner, John Kielkopf, Huigen Liu, Avi Shporer, C. G. Tinney, Hui Zhang, Duncan J. Wright, Brett C. Addison, Matthew W. Mengel, and Jack Okumura

Subjects
Radial velocity, Astronomy, QB1-991
Abstract

We validate the presence of a two-planet system orbiting the 0.15–1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune (TOI 560 b, $P={6.3980661}_{-0.0000097}^{+0.0000095}$ days, $e={0.294}_{-0.062}^{+0.13}$ , $M={0.94}_{-0.23}^{+0.31}{M}_{\mathrm{Nep}}$ ) initially discovered in the Sector 8 Transiting Exoplanet Survey Satellite (TESS) mission observations, and a transiting mini-Neptune (TOI 560 c, $P={18.8805}_{-0.0011}^{+0.0024}$ days, $M={1.32}_{-0.32}^{+0.29}{M}_{\mathrm{Nep}}$ ) discovered in the Sector 34 observations, in a rare near-1:3 orbital resonance. We utilize photometric data from TESS Spitzer, and ground-based follow-up observations to confirm the ephemerides and period of the transiting planets, vet false-positive scenarios, and detect the photoeccentric effect for TOI 560 b. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with the iSHELL spectrograph at the NASA Infrared Telescope Facility and the HIRES Spectrograph at Keck Observatory to validate the planetary nature of these signals, which we combine with published Planet Finder Spectrograph RVs from the Magellan Observatory. We detect the masses of both planets at >3 σ significance. We apply a Gaussian process (GP) model to the TESS light curves to place priors on a chromatic RV GP model to constrain the stellar activity of the TOI 560 host star, and confirm a strong wavelength dependence for the stellar activity demonstrating the ability of near-IR RVs to mitigate stellar activity for young K dwarfs. TOI 560 is a nearby moderately young multiplanet system with two planets suitable for atmospheric characterization with the James Webb Space Telescope and other upcoming missions. In particular, it will undergo six transit pairs separated by

Published
2022
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5. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet

Author

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

Published
2021
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6. HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS

Author

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
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7. TOI-2109: An Ultrahot Gas Giant on a 16 hr Orbit

Author

Ian Wong, Avi Shporer, George Zhou, Daniel Kitzmann, Thaddeus D. Komacek, Xianyu Tan, René Tronsgaard, Lars A. Buchhave, Shreyas Vissapragada, Michael Greklek-McKeon, Joseph E. Rodriguez, John P. Ahlers, Samuel N. Quinn, Elise Furlan, Steve B. Howell, Allyson Bieryla, Kevin Heng, Heather A. Knutson, Karen A. Collins, Kim K. McLeod, Perry Berlind, Peyton Brown, Michael L. Calkins, Jerome P. de Leon, Emma Esparza-Borges, Gilbert A. Esquerdo, Akihiko Fukui, Tianjun Gan, Eric Girardin, Crystal L. Gnilka, Masahiro Ikoma, Eric L. N. Jensen, John Kielkopf, Takanori Kodama, Seiya Kurita, Kathryn V. Lester, Pablo Lewin, Giuseppe Marino, Felipe Murgas, Norio Narita, Enric Pallé, Richard P. Schwarz, Keivan G. Stassun, Motohide Tamura, Noriharu Watanabe, Björn Benneke, George R. Ricker, David W. Latham, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Douglas A. Caldwell, William Fong, Chelsea X. Huang, Ismael Mireles, Joshua E. Schlieder, Bernie Shiao, and Jesus Noel Villaseñor

Subjects
Astronomy
Abstract

We report the discovery of an ultrahot Jupiter with an extremely short orbital period of 0.67247414 ± 0.00000028 days (∼16 hr). The 1.347 ± 0.047 RJup planet, initially identified by the Transiting Exoplanet Survey Satellite (TESS) mission, orbits TOI-2109 (TIC 392476080)—a T(eff) ∼ 6500 K F-type star with a mass of 1.447 ± 0.077 Mꙩ, a radius of 1.698 ± 0.060 Rꙩ, and a rotational velocity of v sin i =81.9 ± 1.7 km/s. The planetary nature of TOI-2109b was confirmed through radial-velocity measurements, which yielded a planet mass of 5.02 ± 0.75 M(Jup). Analysis of the Doppler shadow in spectroscopic transit observations indicates a well-aligned system, with a sky-projected obliquity of λ = 1.°7± 1.°7. From the TESS full-orbit light curve, we measured a secondary eclipse depth of 731 ± 46 ppm, as well as phase-curve variations from the planet's longitudinal brightness modulation and ellipsoidal distortion of the host star. Combining the TESS-band occultation measurement with a K(s)-band secondary eclipse depth (2012 ± 80 ppm) derived from ground-based observations, we find that the dayside emission of TOI-2109b is consistent with a brightness temperature of 3631 ± 69 K, making it the second hottest exoplanet hitherto discovered. By virtue of its extreme irradiation and strong planet–star gravitational interaction, TOI-2109b is an exceptionally promising target for intensive follow-up studies using current and near-future telescope facilities to probe for orbital decay, detect tidally driven atmospheric escape, and assess the impacts of H2 dissociation and recombination on the global heat transport.

Published
2021
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8. Another shipment of six short-period giant planets from TESS

Author

Joseph E Rodriguez, Samuel N Quinn, Andrew Vanderburg, George Zhou, Jason D Eastman, Erica Thygesen, Bryson Cale, David R Ciardi, Phillip A Reed, Ryan J Oelkers, Karen A Collins, Allyson Bieryla, David W Latham, Erica J Gonzales, B Scott Gaudi, Coel Hellier, Matías I Jones, Rafael Brahm, Kirill Sokolovsky, Jack Schulte, Gregor Srdoc, John Kielkopf, Ferran Grau Horta, Bob Massey, Phil Evans, Denise C Stephens, Kim K McLeod, Nikita Chazov, Vadim Krushinsky, Mourad Ghachoui, Boris S Safonov, Cayla M Dedrick, Dennis Conti, Didier Laloum, Steven Giacalone, Carl Ziegler, Pere Guerra Serra, Ramon Naves Nogues, Felipe Murgas, Edward J Michaels, George R Ricker, Roland K Vanderspek, Sara Seager, Joshua N Winn, Jon M Jenkins, Brett Addison, Owen Alfaro, D R Anderson, Elias Aydi, Thomas G Beatty, Timothy R Bedding, Alexander A Belinski, Zouhair Benkhaldoun, Perry Berlind, Cullen H Blake, Michael J Bowen, Brendan P Bowler, Andrew W Boyle, Dalton Branson, César Briceño, Michael L Calkins, Emma Campbell, Jessie L Christiansen, Laura Chomiuk, Kevin I Collins, Matthew A Cornachione, Ahmed Daassou, Courtney D Dressing, Gilbert A Esquerdo, Dax L Feliz, William Fong, Akihiko Fukui, Tianjun Gan, Holden Gill, Maria V Goliguzova, Jarrod Hansen, Thomas Henning, Eric G Hintz, Melissa J Hobson, Jonathan Horner, Chelsea X Huang, David J James, Jacob S Jensen, Samson A Johnson, Andrés Jordán, Stephen R Kane, Khalid Barkaoui, Myung-Jin Kim, Kingsley Kim, Rudolf B Kuhn, Nicholas Law, Pablo Lewin, Hui-Gen Liu, Michael B Lund, Andrew W Mann, Nate McCrady, Matthew W Mengel, Jessica Mink, Lauren G Murphy, Norio Narita, Patrick Newman, Jack Okumura, Hugh P Osborn, Martin Paegert, Enric Palle, Joshua Pepper, Peter Plavchan, Alexander A Popov, Markus Rabus, Jessica Ranshaw, Jennifer A Rodriguez, Dong-Goo Roh, Michael A Reefe, Arjun B Savel, Richard P Schwarz, Avi Shporer, Robert J Siverd, David H Sliski, Keivan G Stassun, Daniel J Stevens, Abderahmane Soubkiou, Eric B Ting, C G Tinney, Noah Vowell, Payton Walton, R G West, Maurice L Wilson, Robert A Wittenmyer, Justin M Wittrock, Shania Wolf, Jason T Wright, Hui Zhang, and Evan Zobel

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Abstract

We present the discovery and characterization of six short-period, transiting giant planets from NASA's Transiting Exoplanet Survey Satellite (TESS) -- TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), & TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9, Comment: 20 Pages, 6 Figures, 8 Tables, Accepted by MNRAS

Published
2023

9. A dense mini-Neptune orbiting the bright young star HD 18599

Author

Jose I Vines, James S Jenkins, Zaira Berdiñas, Maritza G Soto, Matías R Díaz, Douglas R Alves, Mikko Tuomi, Robert A Wittenmyer, Jerome Pitogo de Leon, Pablo Peña, Jack J Lissauer, Sarah Ballard, Timothy Bedding, Brendan P Bowler, Jonathan Horner, Hugh R A Jones, Stephen R Kane, John Kielkopf, Peter Plavchan, Avi Shporer, C G Tinney, Hui Zhang, Duncan J Wright, Brett Addison, Matthew W Mengel, Jack Okumura, and Anya Samadi-Ghadim

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Very little is known about the young planet population because the detection of small planets orbiting young stars is obscured by the effects of stellar activity and fast rotation which mask planets within radial velocity and transit data sets. The few planets that have been discovered in young clusters generally orbit stars too faint for any detailed follow-up analysis. Here we present the characterization of a new mini-Neptune planet orbiting the bright (V=9) and nearby K2 dwarf star, HD 18599. The planet candidate was originally detected in TESS light curves from Sectors 2, 3, 29, and 30, with an orbital period of 4.138~days. We then used HARPS and FEROS radial velocities, to find the companion mass to be 25.5$\pm$4.6~M$_\oplus$. When we combine this with the measured radius from TESS, of 2.70$\pm$0.05~R$_\oplus$, we find a high planetary density of 7.1$\pm$1.4~g cm$^{-3}$. The planet exists on the edge of the Neptune Desert and is the first young planet (300 Myr) of its type to inhabit this region. Structure models argue for a bulk composition to consist of 23% H$_2$O and 77% Rock and Iron. Future follow-up with large ground- and space-based telescopes can enable us to begin to understand in detail the characteristics of young Neptunes in the galaxy., Comment: Accepted in MNRAS

Published
2022

10. TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images

Author

Joseph E. Rodriguez, Samuel N. Quinn, George Zhou, Andrew Vanderburg, Louise D. Nielsen, Robert A. Wittenmyer, Rafael Brahm, Phillip A. Reed, Chelsea X. Huang6, Sydney Vach, David R. Ciardi, Ryan J. Oelkers, Keivan G. Stassun, Coel Hellier, B. Scott Gaudi, Jason D. Eastman, Karen A. Collins, Allyson Bieryla, Sam Christian, David W. Latham, Ilaria Carleo, Duncan J. Wright, Elisabeth Matthews, Erica J. Gonzales, Carl Ziegler, Courtney D. Dressing, Steve B. Howell, Thiam-Guan Tan, Justin Wittrock, Peter Plavchan, Kim K. McLeod, David Baker, Gavin Wang, Don J. Radford, Richard P. Schwarz, Massimiliano Esposito, George R. Ricker, Roland K. Vanderspek, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Brett Addison, D. R. Anderson, Thomas Barclay, Thomas G. Beatty, Perry Berlind, Francois Bouchy, Michael Bowen, Brendan P. Bowler, C. E. Brasseur, César Briceño, Douglas A. Caldwell, Michael L. Calkins, Scott Cartwright, Priyanka Chaturvedi, Guillaume Chaverot, Sudhish Chimaladinne, Jessie L. Christiansen, Kevin I. Collins, Ian J. M. Crossfield, Kevin Eastridge, Néstor Espinoza, Gilbert A. Esquerdo, Dax L. Feliz, Tyler Fenske, William Fong, Tianjun Gan, Steven Giacalone, Holden Gill, Lindsey Gordon, A. Granados, Nolan Grieves, Eike W. Guenther, Natalia Guerrero, Thomas Henning, Christopher E. Henze, Katharine Hesse, Melissa J. Hobson, Jonathan Horner, David J. James, Eric L. N. Jensen, Mary Jimenez, Andres Jordan, Stephen R. Kane, John Kielkopf, Kingsley Kim, Rudolf B. Kuhn, Natasha Latouf2, Nicholas M. Law, Alan M. Levine, Michael B. Lund, Andrew W. Mann, Shude Mao, Rachel A. Matson, Matthew W. Mengel, Jessica Mink, Patrick Newman2, Tanner O Dwyer, Jack Okumura, Enric Palle, Joshua Pepper, Elisa V. Quintana, Paula Sarkis, Arjun B. Savel, Joshua E. Schlieder, Chloe Schnaible, Avi Shporer, Ramotholo Sefako, Julia V. Seidel, Robert J. Siverd, Brett Skinner, Manu Stalport, Daniel J. Stevens, Caitlin Stibbards, C. G. Tinney, R. G. West, Daniel A. Yahalomi, and Hui Zhang

Subjects
Astronomy
Abstract

We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b(TIC 281408474; HD288842), TOI-640 b(TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA’s Transiting Exoplanet Survey Satellite(TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP=1.01–1.77RJ) and have masses that range from 0.85 to 6.33MJ. The host stars of these systems have F and G spectral types (5595Teff 6460 K)and are all relatively bright (9.51.7RJ, possibly a result of its host star’s evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of-+6.310.300.28MJ and a statistically significant, nonzero orbital eccentricity of e=-+0.0740.0220.021. This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P=10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA’s TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals.

Published
2021
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11. TOI-481 b and TOI-892 b: Two Long-period Hot Jupiters from the Transiting Exoplanet Survey Satellite

Author

Rafael Brahm, Louise D. Nielsen, Robert A. Wittenmyer, Songhu Wang, Joseph E. Rodriguez, Néstor Espinoza Perez, Matías I. Jones, Andrés Jordán, Thomas Henning, Melissa J. Hobson, Diana Kossakowski, Felipe Rojas, Paula Sarkis, Martin Schlecker, Trifon Trifonov, Sahar Shahaf, George R Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Brett C. Addison, Gáspár Á. Bakos, Waqas Bhatti, Daniel Bayliss, Perry Berlind, Allyson Bieryla, Francois Bouchy, Brendan P. Bowler, César Briceño, Timothy M. Brown, Edward M. Bryant, Douglas A. Caldwell, David Charbonneau, Karen A. Collins, Allen B. Davis, Gilbert A. Esquerdo, Benjamin J. Fulton, Natalia M. Guerrero, Christopher E. Henze, Aleisha Hogan, Jonathan Horner, Chelsea X. Huang, Jonathan Irwin, Stephen R. Kane, John Kielkopf, Andrew W. Mann, Tsevi Mazeh, James McCormac, Curtis McCully, Matthew W. Mengel, Ismael Mireles, Jack Okumura, Peter Plavchan, Samuel N. Quinn, Markus Rabus, Sophie Saesen, Joshua E. Schlieder, Damien Segransan, Bernie Shiao, Avi Shporer, Robert J. Siverd, Keivan G. Stassun, Vincent Suc, Thiam-Guan Tan, Pascal Torres, Chris G. Tinney, Stephane Udry, Leonardo Vanzi, Michael Vezie, Jose I. Vines, Maja Vuckovic, Duncan J. Wright, Daniel Yahalomi, Abner Zapata, Hui Zhang, and Carl Ziegler

Subjects
Astronomy, Astrophysics
Abstract

We present the discovery of two new 10 day period giant planets from the Transiting Exoplanet Survey Satellite mission, whose masses were precisely determined using a wide diversity of ground-based facilities. TOI-481 b and TOI-892 b have similar radii (0.99 ± 0.01 R(J) and 1.07 ± 0.02 R(J), respectively), and orbital periods (10.3311 days and 10.6266 days, respectively), but significantly different masses (1.53 ± 0.03 M(J) versus 0.95 ± 0.07 M(J), respectively). Both planets orbit metal-rich stars ([Fe/HG] = +0.26 ± 0.05 dex and [Fe/H] = +0.24 ± 0.05 for TOI-481 and TOI-892, respectively) but at different evolutionary stages. TOI-481 is a M(*) = 1.14 ± 0.02 Mꙩ, R(*) = 1.66 ± 0.02 Rꙩ G-type star (T(eff) = 5735 ± 72 K), that with an age of 6.7 Gyr, is in the turn-off point of the main sequence. TOI-892 on the other hand, is a F-type dwarf star (T(eff) = 6261 ± 80 K), which has a mass of M(*) = 1.28 ± 0.03 Mꙩ and a radius of R(*) = 1.39 ± 0.02 Rꙩ. TOI-481 b and TOI-892 b join the scarcely populated region of transiting gas giants with orbital periods longer than 10 days, which is important to constrain theories of the formation and structure of hot Jupiters.

Published
2020
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12. GJ 1252 b: A 1.2 R⊕ Planet Transiting an M3 Dwarf at 20.4 pc

Author

Avi Shporer, Karen A. Collins, Nicola Astudillo-Defru, Jonathan Irwin, Xavier Bonfils, Kevin I. Collins, Elisabeth Matthews, Jennifer G. Winters, David R. Anderson, James D. Armstrong, David Charbonneau, Ryan Cloutier, Tansu Daylan, Tianjun Gan, Maximilian N. Günther, Coel Hellier, Keith Horne, Chelsea X. Huang, Eric L. N. Jensen, John Kielkopf, Enric Palle, Ramotholo Sefako, Keivan G. Stassun, Thiam-Guan Tan, Andrew Vanderburg, George R. Ricker, David W. Latham, Roland Vanderspek, Sara Seager, Joshua N. Winn, Jon M Jenkins, Knicole Colon, Courtney Dressing, Sébastien Léepine, Philip S. Muirhead, Mark E. Rose, Joseph D Twicken, and Jesus Noel Villasenor

Subjects
Astronomy, Astrophysics
Abstract

We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 R⊕ and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 M⊕, 0.391 ± 0.020 R⊕) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Gaia astrometry, and high angular resolution imaging to show that the transit signal seen in the TESS data must originate from a transiting planet. We do so by ruling out all false-positive scenarios that attempt to explain the transit signal as originating from an eclipsing stellar binary. Precise Doppler monitoring also leads to a tentative mass measurement of 2.09 ± 0.56 M⊕. The host star proximity, brightness (V = 12.19 mag, K = 7.92 mag), low stellar activity, and the system's short orbital period make this planet an attractive target for detailed characterization, including precise mass measurement, looking for other objects in the system, and planet atmosphere characterization.

Published
2020
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13. A Mini-Neptune from TESS and CHEOPS Around the 120 Myr Old AB Dor member HIP 94235

Author

George Zhou, Christopher P. Wirth, Chelsea X. Huang, Alexander Venner, Kyle Franson, Samuel N. Quinn, L. G. Bouma, Adam L. Kraus, Andrew W. Mann, Elisabeth. R. Newton, Diana Dragomir, Alexis Heitzmann, Nataliea Lowson, Stephanie T. Douglas, Matthew Battley, Edward Gillen, Amaury Triaud, David W. Latham, Steve B. Howell, J. D. Hartman, Benjamin M. Tofflemire, Robert A. Wittenmyer, Brendan P. Bowler, Jonathan Horner, Stephen R. Kane, John Kielkopf, Peter Plavchan, Duncan J. Wright, Brett C. Addison, Matthew W. Mengel, Jack Okumura, George Ricker, Roland Vanderspek, Sara Seager, Jon M. Jenkins, Joshua N. Winn, Tansu Daylan, Michael Fausnaugh, and Michelle Kunimoto

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Astrophysics - Earth and Planetary Astrophysics
Abstract

The TESS mission has enabled discoveries of the brightest transiting planet systems around young stars. These systems are the benchmarks for testing theories of planetary evolution. We report the discovery of a mini-Neptune transiting a bright star in the AB Doradus moving group. HIP 94235 (TOI-4399, TIC 464646604) is a Vmag=8.31 G-dwarf hosting a 3.00 -0.28/+0.32 Rearth mini-Neptune in a 7.7 day period orbit. HIP 94235 is part of the AB Doradus moving group, one of the youngest and closest associations. Due to its youth, the host star exhibits significant photometric spot modulation, lithium absorption, and X-ray emission. Three 0.06% transits were observed during Sector-27 of the TESS Extended Mission, though these transit signals are dwarfed by the 2% peak-to-peak photometric variability exhibited by the host star. Follow-up observations with CHEOPS confirmed the transit signal and prevented the erosion of the transit ephemeris. HIP 94235 is part of a 50 AU G-M binary system. We make use of diffraction limited observations spanning 11 years, and astrometric accelerations from Hipparchos and Gaia, to constrain the orbit of HIP 94235 B. HIP 94235 is one of the tightest stellar binaries to host an inner planet. As part of a growing sample of bright, young planet systems, HIP 94235 b is ideal for follow-up transit observations, such as those that investigate the evaporative processes driven by high-energy radiation that may sculpt the valleys and deserts in the Neptune population., Accepted for publication in AJ

Published
2022

14. TOI-1842b: A Transiting Warm Saturn Undergoing Reinflation around an Evolving Subgiant

Author

Robert A. Wittenmyer, Jake T. Clark, Trifon Trifonov, Brett C. Addison, Duncan J. Wright, Keivan G. Stassun, Jonathan Horner, Nataliea Lowson, John Kielkopf, Stephen R. Kane, Peter Plavchan, Avi Shporer, Hui Zhang, Brendan P. Bowler, Matthew W. Mengel, Jack Okumura, Markus Rabus, Marshall C. Johnson, Daniel Harbeck, René Tronsgaard, Lars A. Buchhave, Karen A. Collins, Kevin I. Collins, Tianjun Gan, Eric L. N. Jensen, Steve B. Howell, E. Furlan, Crystal L. Gnilka, Kathryn V. Lester, Rachel A. Matson, Nicholas J. Scott, George R. Ricker, Roland Vanderspek, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Alexander Rudat, Elisa V. Quintana, David R. Rodriguez, Douglas A. Caldwell, Samuel N. Quinn, Zahra Essack, and Luke G. Bouma

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The imminent launch of space telescopes designed to probe the atmospheres of exoplanets has prompted new efforts to prioritise the thousands of transiting planet candidates for follow-up characterisation. We report the detection and confirmation of TOI-1842b, a warm Saturn identified by TESS and confirmed with ground-based observations from Minerva-Australis, NRES, and the Las Cumbres Observatory Global Telescope. This planet has a radius of $1.04^{+0.06}_{-0.05}\,R_{Jup}$, a mass of $0.214^{+0.040}_{-0.038}\,M_{Jup}$, an orbital period of $9.5739^{+0.0002}_{-0.0001}$ days, and an extremely low density ($\rho$=0.252$\pm$0.091 g cm$^{-3}$). TOI-1842b has among the best known combinations of large atmospheric scale height (893 km) and host-star brightness ($J=8.747$ mag), making it an attractive target for atmospheric characterisation. As the host star is beginning to evolve off the main sequence, TOI-1842b presents an excellent opportunity to test models of gas giant re-inflation. The primary transit duration of only 4.3 hours also makes TOI-1842b an easily-schedulable target for further ground-based atmospheric characterisation., Comment: Accepted for publication in AJ

Published
2022

15. HD 83443c: A highly eccentric giant planet on a 22-year orbit

Author

Adriana Errico, Robert A. Wittenmyer, Jonathan Horner, Zhexing Li, G. Mirek Brandt, Stephen R. Kane, Tara Fetherolf, Timothy R. Holt, Brad Carter, Jake T. Clark, R. P. Butler, C. G. Tinney, Sarah Ballard, Brendan P. Bowler, John Kielkopf, Huigen Liu, Peter P. Plavchan, Avi Shporer, Hui Zhang, Duncan J. Wright, Brett C. Addison, Matthew W. Mengel, and Jack Okumura

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a highly eccentric long-period Jovian planet orbiting the hot-Jupiter host HD 83443. By combining radial velocity data from four instruments (AAT/UCLES, Keck/HIRES, HARPS, Minerva-Australis) spanning more than two decades, we find evidence for a planet with m sin i = 1.35 − 0.06 + 0.07 M J, moving on an orbit with a = 8.0 ± 0.8 au and eccentricity e = 0.76 ± 0.05. We combine our radial velocity analysis with Gaia eDR3 /Hipparcos proper motion anomalies and derive a dynamical mass of 1.5 − 0.2 + 0.5 M Jup . We perform a detailed dynamical simulation that reveals locations of stability within the system that may harbor additional planets, including stable regions within the habitable zone of the host star. HD 83443 is a rare example of a system hosting a hot Jupiter and an exterior planetary companion. The high eccentricity of HD 83443c suggests that a scattering event may have sent the hot Jupiter to its close orbit while leaving the outer planet on a wide and eccentric path.

Published
2022
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16. TESS Discovery of an Ultra-short-period Planet around the Nearby M Dwarf LHS 3844

Author

Roland Vanderspek, Chelsea X. Huang, Andrew Vanderburg, George R. Ricker, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Jennifer Burt, Jason Dittmann, Elisabeth Newton, Samuel N. Quinn, Avi Shporer, David Charbonneau, Jonathan Irwin, Kristo Ment, Jennifer G. Winters, Karen A. Collins, Phil Evans, Tianjun Gan, Rhodes Hart, Eric L. N. Jensen, John Kielkopf, Shude Mao, William Waalkes, François Bouchy, Maxime Marmier, Louise D. Nielsen, Gaël Ottoni, Francesco Pepe, Damien Ségransan, Stéphane Udry, Todd Henry, Leonardo A. Paredes, Hodari-Sadiki James, Rodrigo H. Hinojosa, Michele L. Silverstein, Enric Palle, Zachory Berta-Thompson, Ian Crossfield, Misty D. Davies, Diana Dragomir, Michael Fausnaugh, Ana Glidden, Joshua Pepper, Edward H. Morgan, Mark Rose, Joseph D. Twicken, Jesus Noel S. Villaseñor, Liang Yu, Gaspar Bakos, Jacob Bean, Lars A. Buchhave, Jørgen Christensen-Dalsgaard, Jessie L. Christiansen, David R. Ciardi, Mark Clampin, Nathan De Lee, Drake Deming, John Doty, J. Garrett Jernigan, Lisa Kaltenegger, Jack J. Lissauer, P. R. McCullough, Norio Narita, Martin Paegert, Andras Pal, Stephen Rinehart, Dimitar Sasselov, Bun’ei Sato, Alessandro Sozzetti, Keivan G. Stassun, and Guillermo Torres

Subjects
Brightness, 010504 meteorology & atmospheric sciences, Doppler spectroscopy, detection [planets and satellites], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Occultation, Atmosphere, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), planetary systems, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Astronomy, Astronomy and Astrophysics, Radius, Exoplanet, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, individual (LHS 3844, TIC 410153553) [stars]
Abstract

Data from the newly-commissioned \textit{Transiting Exoplanet Survey Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf located 15 pc away. The planet has a radius of $1.32\pm 0.02$ $R_\oplus$ and orbits the star every 11 hours. Although the existence of an atmosphere around such a strongly irradiated planet is questionable, the star is bright enough ($I=11.9$, $K=9.1$) for this possibility to be investigated with transit and occultation spectroscopy. The star's brightness and the planet's short period will also facilitate the measurement of the planet's mass through Doppler spectroscopy., 10 pages, 4 figures. Submitted to ApJ Letters. This letter makes use of the TESS Alert data, which is currently in a beta test phase, using data from the pipelines at the TESS Science Office and at the TESS Science Processing Operations Center

Published
2019

17. GJ 1252 b: A 1.2 R ⊕ Planet Transiting an M3 Dwarf at 20.4 pc.

Author

Avi Shporer, Karen A. Collins, Nicola Astudillo-Defru, Jonathan Irwin, Xavier Bonfils, Kevin I. Collins, Elisabeth Matthews, Jennifer G. Winters, David R. Anderson, James D. Armstrong, David Charbonneau, Ryan Cloutier, Tansu Daylan, Tianjun Gan, Maximilian N. Günther, Coel Hellier, Keith Horne, Chelsea X. Huang, Eric L. N. Jensen, and John Kielkopf

Published
2020
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18. Minerva-Australis. I. Design, Commissioning, and First Photometric Results.

Author

Brett Addison, Duncan J. Wright, Robert A. Wittenmyer, Jonathan Horner, Matthew W. Mengel, Daniel Johns, Connor Marti, Belinda Nicholson, Jack Soutter, Brendan Bowler, Ian Crossfield, Stephen R. Kane, John Kielkopf, Peter Plavchan, C. G. Tinney, Hui Zhang, Jake T. Clark, Mathieu Clerte, Jason D. Eastman, and Jon Swift

Subjects
ASTRONOMICAL transits, PLANETARY observations, MASS measurement, STELLAR orbits, PLANETS, PLANETARY orbits
Abstract

The Minerva-Australis telescope array is a facility dedicated to the follow-up, confirmation, characterization, and mass measurement of planets orbiting bright stars discovered by the Transiting Exoplanet Survey Satellite (TESS)—a category in which it is almost unique in the Southern Hemisphere. It is located at the University of Southern Queensland’s Mount Kent Observatory near Toowoomba, Australia. Its flexible design enables multiple 0.7 m robotic telescopes to be used both in combination, and independently, for high-resolution spectroscopy and precision photometry of TESS transit planet candidates. Minerva-Australis also enables complementary studies of exoplanet spin–orbit alignments via Doppler observations of the Rossiter–McLaughlin effect, radial velocity searches for nontransiting planets, planet searches using transit timing variations, and ephemeris refinement for TESS planets. In this first paper, we describe the design, photometric instrumentation, software, and science goals of Minerva-Australis, and note key differences from its Northern Hemisphere counterpart, the Minerva array. We use recent transit observations of four planets, WASP-2b, WASP-44b, WASP-45b, and HD 189733b, to demonstrate the photometric capabilities of Minerva-Australis. [ABSTRACT FROM AUTHOR]

Published
2019
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