22 results on '"R. D. Haywood"'
Search Results
2. TOI-4010: A System of Three Large Short-period Planets with a Massive Long-period Companion
- Author
-
Michelle Kunimoto, Andrew Vanderburg, Chelsea X. Huang, M. Ryleigh Davis, Laura Affer, Andrew Collier Cameron, David Charbonneau, Rosario Cosentino, Mario Damasso, Xavier Dumusque, A. F. Martnez Fiorenzano, Adriano Ghedina, R. D. Haywood, Florian Lienhard, Mercedes López-Morales, Michel Mayor, Francesco Pepe, Matteo Pinamonti, Ennio Poretti, Jesús Maldonado, Ken Rice, Alessandro Sozzetti, Thomas G. Wilson, Stéphane Udry, Jay Baptista, Khalid Barkaoui, Juliette Becker, Paul Benni, Allyson Bieryla, Pau Bosch-Cabot, David R. Ciardi, Karen A. Collins, Kevin I. Collins, Elise Evans, Trent J. Dupuy, Maria V. Goliguzova, Pere Guerra, Adam Kraus, Jack J. Lissauer, Daniel Huber, Felipe Murgas, Enric Palle, Samuel N. Quinn, Boris S. Safonov, Richard P. Schwarz, Avi Shporer, Keivan G. Stassun, Jon M. Jenkins, David W. Latham, George R. Ricker, Sara Seager, Roland Vanderspek, Joshua Winn, Zahra Essack, Hannah M. Lewis, and Mark E. Rose
- Subjects
Exoplanets ,Hot Neptunes ,Exoplanet systems ,Transit photometry ,Exoplanet dynamics ,Astronomy ,QB1-991 - Abstract
We report the confirmation of three exoplanets transiting TOI-4010 (TIC-352682207), a metal-rich K dwarf observed by the Transiting Exoplanet Survey Satellite in Sectors 24, 25, 52, and 58. We confirm these planets with the High Accuracy Radial velocity Planet Searcher for the Northern Hemisphere radial velocity observations and measure their masses with 8−12% precision. TOI-4010 b is a sub-Neptune ( P = 1.3 days, ${R}_{p}={3.02}_{-0.08}^{+0.08}\,{R}_{\oplus }$ , ${M}_{p}={11.00}_{-1.27}^{+1.29}\,{M}_{\oplus }$ ) in the hot-Neptune desert, and is one of the few such planets with known companions. Meanwhile, TOI-4010 c ( P = 5.4 days, ${R}_{p}={5.93}_{-0.12}^{+0.11}\,{R}_{\oplus }$ , ${M}_{p}={20.31}_{-2.11}^{+2.13}\,{M}_{\oplus }$ ) and TOI-4010 d ( P = 14.7 days, ${R}_{p}={6.18}_{-0.14}^{+0.15}\,{R}_{\oplus }$ , ${M}_{p}={38.15}_{-3.22}^{+3.27}\,{M}_{\oplus }$ ) are similarly sized sub-Saturns on short-period orbits. Radial velocity observations also reveal a super-Jupiter-mass companion called TOI-4010 e in a long-period, eccentric orbit ( P ∼ 762 days and e ∼ 0.26 based on available observations). TOI-4010 is one of the few systems with multiple short-period sub-Saturns to be discovered so far.
- Published
- 2023
- Full Text
- View/download PDF
3. Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass
- Author
-
Andrew W. Mayo, Courtney D. Dressing, Andrew Vanderburg, Charles D. Fortenbach, Florian Lienhard, Luca Malavolta, Annelies Mortier, Alejandro Núñez, Tyler Richey-Yowell, Emma V. Turtelboom, Aldo S. Bonomo, David W. Latham, Mercedes López-Morales, Evgenya Shkolnik, Alessandro Sozzetti, Marcel A. Agüeros, Luca Borsato, David Charbonneau, Rosario Cosentino, Stephanie T. Douglas, Xavier Dumusque, Adriano Ghedina, Rose Gibson, Valentina Granata, Avet Harutyunyan, R. D. Haywood, Gaia Lacedelli, Vania Lorenzi, Antonio Magazzù, A. F. Martinez Fiorenzano, Giuseppina Micela, Emilio Molinari, Marco Montalto, Domenico Nardiello, Valerio Nascimbeni, Isabella Pagano, Giampaolo Piotto, Lorenzo Pino, Ennio Poretti, Gaetano Scandariato, Stephane Udry, and Lars A. Buchhave
- Subjects
Exoplanets ,Exoplanet systems ,Exoplanet atmospheres ,Exoplanet detection methods ,Radial velocity ,Transits ,Astronomy ,QB1-991 - Abstract
K2-136 is a late-K dwarf (0.742 ± 0.039 M _⊙ ) in the Hyades open cluster with three known, transiting planets and an age of 650 ± 70 Myr. Analyzing K2 photometry, we found that planets K2-136b, c, and d have periods of 8.0, 17.3, and 25.6 days and radii of 1.014 ± 0.050 R _⊕ , 3.00 ± 0.13 R _⊕ , and 1.565 ± 0.077 R _⊕ , respectively. We collected 93 radial velocity (RV) measurements with the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph (Telescopio Nazionale Galileo) and 22 RVs with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectrograph (Very Large Telescope). Analyzing HARPS-N and ESPRESSO data jointly, we found that K2-136c induced a semi-amplitude of 5.49 ± 0.53 m s ^−1 , corresponding to a mass of 18.1 ± 1.9 M _⊕ . We also placed 95% upper mass limits on K2-136b and d of 4.3 and 3.0 M _⊕ , respectively. Further, we analyzed Hubble Space Telescope and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has ∼75% the radius of Neptune but is similar in mass, yielding a density of ${3.69}_{-0.56}^{+0.67}$ g cm ^−3 (∼2–3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets’ atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time.
- Published
- 2023
- Full Text
- View/download PDF
4. Independent Validation of the Temperate Super-Earth HD 79211 b using HARPS-N
- Author
-
Victoria DiTomasso, Chantanelle Nava, Mercedes López-Morales, Allyson Bieryla, Ryan Cloutier, Luca Malavolta, Annelies Mortier, Lars A. Buchhave, Keivan G. Stassun, Alessandro Sozzetti, Aldo Stefano Bonomo, David Charbonneau, Andrew Collier Cameron, Rosario Cosentino, Mario Damasso, Xavier Dumusque, A. F. Martínez Fiorenzano, Adriano Ghedina, Avet Harutyunyan, R. D. Haywood, David Latham, Emilio Molinari, Francesco A. Pepe, Matteo Pinamonti, Ennio Poretti, Ken Rice, Dimitar Sasselov, Manu Stalport, Stéphane Udry, Christopher Watson, and Thomas G. Wilson
- Subjects
Exoplanet detection methods ,Radial velocity ,M dwarf stars ,Binary stars ,Astronomy ,QB1-991 - Abstract
We present high-precision radial velocities (RVs) from the HARPS-N spectrograph for HD 79210 and HD 79211, two M0V members of a gravitationally bound binary system. We detect a planet candidate with a period of ${24.421}_{-0.017}^{+0.016}$ days around HD 79211 in these HARPS-N RVs, validating the planet candidate originally identified in CARMENES RV data alone. Using HARPS-N, CARMENES, and RVs spanning a total of 25 yr, we further refine the planet candidate parameters to P = 24.422 ± 0.014 days, K = 3.19 ± 0.27 m s ^−1 , M sin i = 10.6 ± 1.2 M _⊕ , and a = 0.142 ± 0.005 au. We do not find any additional planet candidate signals in the data of HD 79211, nor do we find any planet candidate signals in HD 79210. This system adds to the number of exoplanets detected in binaries with M-dwarf members and serves as a case study for planet formation in stellar binaries.
- Published
- 2023
- Full Text
- View/download PDF
5. Investigating the architecture and internal structure of the TOI-561 system planets with CHEOPS, HARPS-N, and TESS
- Author
-
G Lacedelli, T G Wilson, L Malavolta, M J Hooton, A Collier Cameron, Y Alibert, A Mortier, A Bonfanti, R D Haywood, S Hoyer, G Piotto, A Bekkelien, A M Vanderburg, W Benz, X Dumusque, A Deline, M López-Morales, L Borsato, K Rice, L Fossati, D W Latham, A Brandeker, E Poretti, S G Sousa, A Sozzetti, S Salmon, C J Burke, V Van Grootel, M M Fausnaugh, V Adibekyan, C X Huang, H P Osborn, A J Mustill, E Pallé, V Bourrier, V Nascimbeni, R Alonso, G Anglada, T Bárczy, D Barrado y Navascues, S C C Barros, W Baumjohann, M Beck, T Beck, N Billot, X Bonfils, C Broeg, L A Buchhave, J Cabrera, S Charnoz, R Cosentino, Sz Csizmadia, M B Davies, M Deleuil, L Delrez, O Demangeon, B -O Demory, D Ehrenreich, A Erikson, E Esparza-Borges, H G Florén, A Fortier, M Fridlund, D Futyan, D Gandolfi, A Ghedina, M Gillon, M Güdel, P Guterman, A Harutyunyan, K Heng, K G Isaak, J M Jenkins, L Kiss, J Laskar, A Lecavelier des Etangs, M Lendl, C Lovis, D Magrin, L Marafatto, A F Martinez Fiorenzano, P F L Maxted, M Mayor, G Micela, E Molinari, F Murgas, N Narita, G Olofsson, R Ottensamer, I Pagano, A Pasetti, M Pedani, F A Pepe, G Peter, D F Phillips, D Pollacco, D Queloz, R Ragazzoni, N Rando, F Ratti, H Rauer, I Ribas, N C Santos, D Sasselov, G Scandariato, S Seager, D Ségransan, L M Serrano, A E Simon, A M S Smith, M Steinberger, M Steller, Gy Szabó, N Thomas, J D Twicken, S Udry, N Walton, and J N Winn
- Published
- 2022
- Full Text
- View/download PDF
6. Separating planetary reflex Doppler shifts from stellar variability in the wavelength domain
- Author
-
A Collier Cameron, E B Ford, S Shahaf, S Aigrain, X Dumusque, R D Haywood, A Mortier, D F Phillips, L Buchhave, M Cecconi, H Cegla, R Cosentino, M Crétignier, A Ghedina, M González, D W Latham, M Lodi, M López-Morales, G Micela, E Molinari, F Pepe, G Piotto, E Poretti, D Queloz, J San Juan, D Ségransan, A Sozzetti, A Szentgyorgyi, S Thompson, S Udry, and C Watson
- Published
- 2021
- Full Text
- View/download PDF
7. The spectral impact of magnetic activity on disc-integrated HARPS-N solar observations: exploring new activity indicators
- Author
-
A P G Thompson, C A Watson, R D Haywood, J C Costes, E de Mooij, A Collier Cameron, X Dumusque, D F Phillips, S H Saar, A Mortier, T W Milbourne, S Aigrain, H M Cegla, D Charbonneau, R Cosentino, A Ghedina, D W Latham, M López-Morales, G Micela, E Molinari, E Poretti, A Sozzetti, S Thompson, and R Walsworth
- Published
- 2020
- Full Text
- View/download PDF
8. Three years of Sun-as-a-star radial-velocity observations on the approach to solar minimum
- Author
-
A Collier Cameron, A Mortier, D Phillips, X Dumusque, R D Haywood, N Langellier, C A Watson, H M Cegla, J Costes, D Charbonneau, A Coffinet, D W Latham, M Lopez-Morales, L Malavolta, J Maldonado, G Micela, T Milbourne, E Molinari, S H Saar, S Thompson, N Buchschacher, M Cecconi, R Cosentino, A Ghedina, A Glenday, M Gonzalez, C-H Li, M Lodi, C Lovis, F Pepe, E Poretti, K Rice, D Sasselov, A Sozzetti, A Szentgyorgyi, S Udry, and R Walsworth
- Published
- 2019
- Full Text
- View/download PDF
9. Reducing activity-induced variations in a radial-velocity time series of the Sun as a star
- Author
-
A F Lanza, A Collier Cameron, and R D Haywood
- Published
- 2019
- Full Text
- View/download PDF
10. Masses and radii for the three super-Earths orbiting GJ 9827, and implications for the composition of small exoplanets
- Author
-
K Rice, L Malavolta, A Mayo, A Mortier, L A Buchhave, L Affer, A Vanderburg, M Lopez-Morales, E Poretti, L Zeng, A C Cameron, M Damasso, A Coffinet, D W Latham, A S Bonomo, F Bouchy, D Charbonneau, X Dumusque, P Figueira, A F Martinez Fiorenzano, R D Haywood, J Asher Johnson, E Lopez, C Lovis, M Mayor, G Micela, E Molinari, V Nascimbeni, C Nava, F Pepe, D F Phillips, G Piotto, D Sasselov, D Ségransan, A Sozzetti, S Udry, and C Watson
- Published
- 2019
- Full Text
- View/download PDF
11. K2-263 b: a 50 d period sub-Neptune with a mass measurement using HARPS-N
- Author
-
A Mortier, A S Bonomo, V M Rajpaul, L A Buchhave, A Vanderburg, L Zeng, M López-Morales, L Malavolta, A Collier Cameron, C D Dressing, P Figueira, V Nascimbeni, K Rice, A Sozzetti, C Watson, L Affer, F Bouchy, D Charbonneau, A Harutyunyan, R D Haywood, J A Johnson, D W Latham, C Lovis, A F Martinez Fiorenzano, M Mayor, G Micela, E Molinari, F Motalebi, F Pepe, G Piotto, D Phillips, E Poretti, D Sasselov, D Ségransan, and S Udry
- Published
- 2018
- Full Text
- View/download PDF
12. Detection Limits of Low-mass, Long-period Exoplanets Using Gaussian Processes Applied to HARPS-N Solar Radial Velocities
- Author
-
N. Langellier, T. W. Milbourne, D. F. Phillips, R. D. Haywood, S. H. Saar, A. Mortier, L. Malavolta, S. Thompson, A. Collier Cameron, X. Dumusque, H. M. Cegla, D. W. Latham, J. Maldonado, C. A. Watson, N. Buchschacher, M. Cecconi, D. Charbonneau, R. Cosentino, A. Ghedina, M. Gonzalez, C-H. Li, M. Lodi, M. López-Morales, G. Micela, E. Molinari, F. Pepe, E. Poretti, K. Rice, D. Sasselov, A. Sozzetti, S. Udry, and R. L. Walsworth
- Published
- 2021
- Full Text
- View/download PDF
13. Unsigned magnetic flux as a proxy for radial-velocity variations in sun-like stars
- Author
-
R. D. Haywood, T. W. Milbourne, S. H. Saar, A. Mortier, D. Phillips, D. Charbonneau, A. Collier Cameron, H. M. Cegla, N. Meunier, M. L. Palumbo III, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, University of St Andrews. St Andrews Centre for Exoplanet Science, Haywood, RD [0000-0001-9140-3574], Saar, SH [0000-0001-7032-8480], Mortier, A [0000-0001-7254-4363], Phillips, D [0000-0001-5132-1339], Charbonneau, D [0000-0002-9003-484X], Cameron, AC [0000-0002-8863-7828], Cegla, HM [0000-0001-8934-7315], Iii, MLP [0000-0002-4677-8796], and Apollo - University of Cambridge Repository
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Solar faculae ,Radial velocity ,astro-ph.SR ,Sunspots ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quiet sun ,3rd-DAS ,Solar cycle ,Active sun ,QC Physics ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,astro-ph.EP ,Astronomy data analysis ,Astrophysics::Solar and Stellar Astrophysics ,Exoplanet detection methods ,QB Astronomy ,Astrophysics::Earth and Planetary Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,QC ,Astrophysics - Earth and Planetary Astrophysics ,QB - Abstract
We estimate disc-averaged RV variations of the Sun over the last magnetic cycle, from the single Fe I line observed by SDO/HMI, using a physical model for rotationally modulated magnetic activity that was previously validated against HARPS-N solar observations. We estimate the disc-averaged, unsigned magnetic flux and show that a simple linear fit to it reduces the RMS of RV variations by 62%, i.e. a factor of 2.6. We additionally apply the FF' method, which predicts RV variations based on a star's photometric variations. At cycle maximum, we find that additional physical processes must be at play beyond suppression of convective blueshift and velocity imablances resulting from brightness inhomogeneities, in agreement with recent studies of solar RV variations. By modelling RV variations over the magnetic cycle using a linear fit to the unsigned magnetic flux, we recover injected planets at an orbital period of about 300 days with RV semi-amplitudes down to 0.3 m/s. To reach semi-amplitudes of 0.1 m/s, we will need to identify and model additional physical phenomena that are not well traced by the unsigned magnetic flux or FF'. The unsigned magnetic flux is an excellent proxy for rotationally modulated, activity-induced RV variations, and could become a key tool in confirming and characterising Earth analogs orbiting Sun-like stars. The present study motivates ongoing and future efforts to develop observation and analysis techniques to measure the unsigned magnetic flux at high precision in slowly rotating, relatively inactive stars like the Sun., 25 pages, 11 figures, 3 tables, submitted to ApJ
- Published
- 2022
14. TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley
- Author
-
Gilbert A. Esquerdo, Walter Boschin, Lars A. Buchhave, Allyson Bieryla, Karen A. Collins, Eric L. N. Jensen, Nobuhiko Kusakabe, David F. Phillips, Chelsea X. Huang, Jack J. Lissauer, Steve B. Howell, Norio Narita, E. Girardin, Christopher A. Watson, Enric Palle, Damien Ségransan, R. D. Haywood, P. Guerra, David W. Latham, S. Giacalone, Jonathan Irwin, Avi Shporer, Keivan G. Stassun, Giampaolo Piotto, E. Esparza-Borges, Gloria Andreuzzi, Felipe Murgas, Marco Pedani, Francesco Pepe, Mercedes Lopez-Morales, Scott McDermott, Courtney D. Dressing, Robert Massey, Motohide Tamura, George R. Ricker, Annelies Mortier, Giuseppina Micela, Jessie L. Christiansen, Emilio Molinari, Pau Bosch-Cabot, Jon M. Jenkins, Roland Vanderspek, Aldo F. M. Fiorenzano, Samuel N. Quinn, Hannu Parviainen, Ken Rice, Avet Harutyunyan, Akihiko Fukui, Sara Seager, Elisa V. Quintana, Massimo Cecconi, Mark E. Rose, R. Cloutier, Luca Di Fabrizio, Joshua N. Winn, Alessandro Sozzetti, Arjun B. Savel, Andrew Collier Cameron, David Charbonneau, Rachel A. Matson, Michel Mayor, Dimitar Sasselov, Christophe Lovis, Stéphane Udry, Gábor Fűrész, Xavier Dumusque, Cloutier, R [0000-0001-5383-9393], Charbonneau, D [0000-0002-9003-484X], Stassun, KG [0000-0002-3481-9052], Murgas, F [0000-0001-9087-1245], Mortier, A [0000-0001-7254-4363], Massey, R [0000-0001-8879-7138], Lissauer, JJ [0000-0001-6513-1659], Latham, DW [0000-0001-9911-7388], Haywood, RD [0000-0001-9140-3574], Guerra, P [0000-0002-4308-2339], Giacalone, SA [0000-0002-8965-3969], Bieryla, A [0000-0001-6637-5401], Winn, J [0000-0002-4265-047X], Watson, CA [0000-0002-9718-3266], Vanderspek, R [0000-0001-6763-6562], Udry, S [0000-0001-7576-6236], Tamura, M [0000-0002-6510-0681], Sozzetti, A [0000-0002-7504-365X], Shporer, A [0000-0002-1836-3120], Ségransan, D [0000-0003-2355-8034], Seager, S [0000-0002-6892-6948], Savel, AB [0000-0002-2454-768X], Sasselov, D [0000-0001-7014-1771], Rose, M [0000-0003-4724-745X], Ricker, G [0000-0003-2058-6662], Rice, K [0000-0002-6379-9185], Quintana, EV [0000-0003-1309-2904], Quinn, SN [0000-0002-8964-8377], Piotto, G [0000-0002-9937-6387], Phillips, D [0000-0001-5132-1339], Pedani, M [0000-0002-5752-6260], Parviainen, H [0000-0001-5519-1391], Palle, E [0000-0003-0987-1593], Narita, N [0000-0001-8511-2981], Molinari, E [0000-0002-1742-7735], Micela, G [0000-0002-9900-4751], Mayor, M [0000-0002-9352-5935], Matson, RA [0000-0001-7233-7508], López-Morales, M [0000-0003-3204-8183], Kusakabe, N [0000-0001-9194-1268], Jensen, ELN [0000-0002-4625-7333], Jenkins, JM [0000-0002-4715-9460], Huang, CX [0000-0003-0918-7484], Howell, SB [0000-0002-2532-2853], Fukui, A [0000-0002-4909-5763], Esquerdo, GA [0000-0002-9789-5474], Esparza-Borges, E [0000-0002-2341-3233], Dumusque, X [0000-0002-9332-2011], Dressing, CD [0000-0001-8189-0233], Collins, KA [0000-0001-6588-9574], Cameron, AC [0000-0002-8863-7828], Christiansen, JL [0000-0002-8035-4778], Buchhave, LA [0000-0003-1605-5666], Boschin, W [0000-0001-9978-9109], Apollo - University of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
- Subjects
Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Radial velocity ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,Radius ,3rd-DAS ,Sitting ,Exoplantet strcuture ,QC Physics ,Space and Planetary Science ,Planet ,astro-ph.EP ,Period (geology) ,QB Astronomy ,Planetary system formation ,Low mass stars ,Astrophysics::Earth and Planetary Astrophysics ,Transit photometry ,QC ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,QB - Abstract
Studies of close-in planets orbiting M dwarfs have suggested that the M dwarf radius valley may be well-explained by distinct formation timescales between enveloped terrestrials, and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally-driven mass loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short period planet TOI-1634 b ($P=0.989$ days, $F=121 F_{\oplus}$, $r_p = 1.790^{+0.080}_{-0.081} R_{\oplus}$) orbiting a nearby M2 dwarf ($K_s=8.7$, $R_s=0.45 R_{\odot}$, $M_s=0.50 M_{\odot}$) and whose size and orbital period sit within the M dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of $4.91^{+0.68}_{-0.70} M_{\oplus}$, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma$ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky portion that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of the Earth favors the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with $M_s\lesssim 0.5 M_{\odot}$., Comment: 27 pages, 13 figures, accepted to AAS journals. Our time series are included as a csv file in the arXiv source files
- Published
- 2021
15. Detection Limits of Low-mass, Long-period Exoplanets Using Gaussian Processes Applied to HARPS-N Solar Radial Velocities
- Author
-
Christopher A. Watson, M. Lopez-Morales, Massimo Cecconi, L. Malavolta, R. D. Haywood, Timothy Milbourne, M. Gonzalez, Dimitar Sasselov, David F. Phillips, Xavier Dumusque, J. Maldonado, Ken Rice, H. M. Cegla, S. H. Saar, Stéphane Udry, Rosario Cosentino, D. W. Latham, N. Buchschacher, Elisa Molinari, Ronald L. Walsworth, Adriano Ghedina, Giuseppina Micela, Francesco Pepe, Alessandro Sozzetti, C. H. Li, Susan E. Thompson, D. Charbonneau, E. Poretti, Annelies Mortier, Nicholas Langellier, A. Collier Cameron, Marcello Lodi, Langellier, N [0000-0003-2107-3308], Milbourne, TW [0000-0001-5446-7712], Phillips, DF [0000-0001-5132-1339], Haywood, RD [0000-0001-9140-3574], Saar, SH [0000-0001-7032-8480], Mortier, A [0000-0001-7254-4363], Malavolta, L [0000-0002-6492-2085], Thompson, S [0000-0002-8039-194X], Cameron, AC [0000-0002-8863-7828], Dumusque, X [0000-0002-9332-2011], Cegla, HM [0000-0001-8934-7315], Latham, DW [0000-0001-9911-7388], Maldonado, J [0000-0002-2218-5689], Buchschacher, N [0000-0002-3697-1541], Cecconi, M [0000-0001-5701-2529], Charbonneau, D [0000-0002-9003-484X], Cosentino, R [0000-0003-1784-1431], Ghedina, A [0000-0003-4702-5152], Lodi, M [0000-0002-5432-9659], López-Morales, M [0000-0003-3204-8183], Micela, G [0000-0002-9900-4751], Molinari, E [0000-0002-1742-7735], Poretti, E [0000-0003-1200-0473], Rice, K [0000-0002-6379-9185], Sasselov, D [0000-0001-7014-1771], Sozzetti, A [0000-0002-7504-365X], Udry, S [0000-0001-7576-6236], Walsworth, RL [0000-0003-0311-4751], Apollo - University of Cambridge Repository, Science & Technology Facilities Council, University of St Andrews. School of Physics and Astronomy, and University of St Andrews. St Andrews Centre for Exoplanet Science
- Subjects
Radial velocity ,astro-ph.SR ,Solar activity ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,010309 optics ,symbols.namesake ,Long period ,0103 physical sciences ,QB Astronomy ,Astrophysics::Solar and Stellar Astrophysics ,Gaussian regression ,010303 astronomy & astrophysics ,Gaussian process ,QC ,Astrophysics::Galaxy Astrophysics ,QB ,Physics ,Detection limit ,Exoplanets ,DAS ,Astronomy and Astrophysics ,Exoplanet ,QC Physics ,13. Climate action ,Space and Planetary Science ,astro-ph.EP ,symbols ,Astrophysics::Earth and Planetary Astrophysics ,Low Mass ,astro-ph.IM - Abstract
Funding: A.C.C. acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant No. ST/R000824/1. Radial velocity (RV) searches for Earth-mass exoplanets in the habitable zone around Sun-like stars are limited by the effects of stellar variability on the host star. In particular, suppression of convective blueshift and brightness inhomogeneities due to photospheric faculae/plage and starspots are the dominant contribution to the variability of such stellar RVs. Gaussian process (GP) regression is a powerful tool for statistically modeling these quasi-periodic variations. We investigate the limits of this technique using 800 days of RVs from the solar telescope on the High Accuracy Radial velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph. These data provide a well-sampled time series of stellar RV variations. Into this data set, we inject Keplerian signals with periods between 100 and 500 days and amplitudes between 0.6 and 2.4 m s−1. We use GP regression to fit the resulting RVs and determine the statistical significance of recovered periods and amplitudes. We then generate synthetic RVs with the same covariance properties as the solar data to determine a lower bound on the observational baseline necessary to detect low-mass planets in Venus-like orbits around a Sun-like star. Our simulations show that discovering planets with a larger mass (~0.5 m s−1) using current-generation spectrographs and GP regression will require more than 12 yr of densely sampled RV observations. Furthermore, even with a perfect model of stellar variability, discovering a true exo-Venus (~0.1 m s−1) with current instruments would take over 15 yr. Therefore, next-generation spectrographs and better models of stellar variability are required for detection of such planets. Postprint
- Published
- 2021
16. III.2 Activity modelling and impact on planet’s parameters The case of CoRoT7
- Author
-
S. C. C. Barros, R. D. Haywood, and M. Deleuil
- Published
- 2020
17. Radial-velocity fitting challenge. II. First results of the analysis of the data set
- Author
-
X. Dumusque, F. Borsa, M. Damasso, R. F. Díaz, P. C. Gregory, N. C. Hara, A. Hatzes, V. Rajpaul, M. Tuomi, S. Aigrain, G. Anglada-Escudé, A. S. Bonomo, G. Boué, F. Dauvergne, G. Frustagli, P. Giacobbe, R. D. Haywood, H. R. A. Jones, J. Laskar, M. Pinamonti, E. Poretti, M. Rainer, D. Ségransan, A. Sozzetti, S. Udry, Dumusque, X., Borsa, F., Damasso, M., Dãaz, R. F., Gregory, P. C., Hara, N. C., Hatzes, A., Rajpaul, V., Tuomi, M., Aigrain, S., Anglada Escudé, G., Bonomo, A. S., Bouã©, G., Dauvergne, F., Frustagli, G., Giacobbe, Paolo, Haywood, R. D., Jones, H. R. A., Laskar, J., Pinamonti, Matteo, Poretti, E., Rainer, M., Sã©gransan, D., Sozzetti, A., Udry, S., ITA, USA, GBR, CHE, Observatoire de Genève, INAF-Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807, Merate (LC), Italy, INAF-Osservatorio Astrofisico di Torino, via Osservatorio 20, 10025, Pino Torinese, Italy, Department of Physics and Astronomy, University of British Columbia, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astronomie et systèmes dynamiques (ASD), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Türinger Landessternwarte Tautenburg, Department of Physics, Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Harvard-Smithsonian Center for Astrophysics, and Dipartimento di Fisica, Università di Genova e Sezione INFN
- Subjects
Stars: activity ,oscillations [stars] ,Planetary system ,Ciencias Físicas ,FOS: Physical sciences ,Star (graph theory) ,01 natural sciences ,Signal ,purl.org/becyt/ford/1 [https] ,Methods: data analysis ,Planet ,Planetary systems ,Stars: oscillations ,Techniques: radial velocities ,Astronomy and Astrophysics ,Space and Planetary Science ,0103 physical sciences ,data analysis [methods] ,Limit (mathematics) ,010306 general physics ,010303 astronomy & astrophysics ,planetary systems ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,activity [stars] ,radial velocitie [Techniques] ,oscillation [Stars] ,radial velocities [techniques] ,purl.org/becyt/ford/1.3 [https] ,Astronomy and Astrophysic ,Computational physics ,Radial velocity ,Data set ,data analysi [Methods] ,Astronomía ,Orbit ,13. Climate action ,Astrophysics::Earth and Planetary Astrophysics ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Order of magnitude ,CIENCIAS NATURALES Y EXACTAS ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Radial-velocity (RV) signals induce RV variations an order of magnitude larger than the signal created by the orbit of Earth-twins, thus preventing their detection. The goal of this paper is to compare the efficiency of the different methods used to deal with stellar signals to recover extremely low-mass planets despite. However, because observed RV variations at the m/s precision level or below is a combination of signals induced by unresolved orbiting planets, by the star, and by the instrument, performing such a comparison using real data is extremely challenging. To circumvent this problem, we generated simulated RV measurements including realistic stellar and planetary signals. Different teams analyzed blindly those simulated RV measurements, using their own method to recover planetary signals despite stellar RV signals. By comparing the results obtained by the different teams with the planetary and stellar parameters used to generate the simulated RVs, it is therefore possible to compare the efficiency of these different methods. The most efficient methods to recover planetary signals {take into account the different activity indicators,} use red-noise models to account for stellar RV signals and a Bayesian framework to provide model comparison in a robust statistical approach. Using the most efficient methodology, planets can be found down to K/N= K_pl/RV_rms*sqrt{N_obs}=5 with a threshold of K/N=7.5 at the level of 80-90% recovery rate found for a number of methods. These recovery rates drop dramatically for K/N smaller than this threshold. In addition, for the best teams, no false positives with K/N > 7.5 were detected, while a non-negligible fraction of them appear for smaller K/N. A limit of K/N = 7.5 seems therefore a safe threshold to attest the veracity of planetary signals for RV measurements with similar properties to those of the different RV fitting challenge systems., 36 pages (including 10 pages of appendix), 23 figures, Accepted in A&A
- Published
- 2017
18. The HARPS-N Rocky Planet Search: I. HD219134 b: A transiting rocky planet in a multi-planet system at 6.5 pc from the Sun
- Author
-
M. Lopez-Morales, D. Segransan, G. Piotto, Giuseppina Micela, Dimitar Sasselov, D. Philips, Annelies Mortier, P. Figueira, Francesco Pepe, A. Collier Cameron, Lars A. Buchhave, V. Nascimbeni, S. Gettel, A. F. M. Fiorenzano, Andrew Vanderburg, Laura Affer, M. Mayor, D. L. Pollacco, Ken Rice, John Asher Johnson, Eric D. Lopez, Alessandro Sozzetti, R. D. Haywood, Courtney D. Dressing, Christopher A. Watson, Ararat Harutyunyan, Fatemeh Motalebi, Stéphane Udry, Rosario Cosentino, D. W. Latham, C. Lovis, B. O. Demory, A. S. Bonomo, Xavier Dumusque, M. Gillon, Luca Malavolta, D. Queloz, Emilio Molinari, D. Charbonneau, ITA, USA, GBR, ESP, BEL, DNK, PRT, and CHE
- Subjects
Rotation period ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Star (game theory) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Orbital eccentricity ,radial velocities [techniques] ,Astrophysics ,Planetary system ,photometric [techniques] ,Orbit ,eclipsing [binaries] ,Space and Planetary Science ,Planet ,individual: HD 219134 [stars] ,Transit (astronomy) ,spectrographs [Instrumentation] ,Planetary mass ,Astrophysics - Earth and Planetary Astrophysics - Abstract
We present here the detection of a system of four low-mass planets around the bright (V=5.5) and close-by (6.5 pc) star HD219134. This is the first result of the Rocky Planet Search program with HARPS-N on the TNG in La Palma. The inner planet orbits the star in 3.0937 +/-0.0004 days, on a quasi-circular orbit with a semi-major axis of 0.0382 +/- 0.0003 AU. Spitzer observations allowed us to detect the transit of the planet in front of the star making HD219134b the nearest known transiting planet to date. From the amplitude of the radial-velocity variation (2.33 +/- 0.24 m/s) and observed depth of the transit (359 +/- 38 ppm), the planet mass and radius are estimated to be 4.46 +/- 0.47 M_{\oplus} and 1.606 +/- 0.086 R_{\oplus} leading to a mean density of 5.89 +/- 1.17 g/cc, suggesting a rocky composition. One additional planet with minimum mass of 2.67 +/- 0.59 M_{\oplus} moves on a close-in, quasi-circular orbit with a period of 6.765 +/- 0.005 days. The third planet in the system has a period of 46.78 +/- 0.16 days and a minimum mass of 8.7 +/- 1.1 M{\oplus}, at 0.234 +/- 0.002 AU from the star. Its eccentricity is 0.32 +/- 0.14. The period of this planet is close to the rotational period of the star estimated from variations of activity indicators (42.3 +/- 0.1 days). The planetary origin of the signal is, however, the preferred solution as no indication of variation at the corresponding frequency is observed for activity-sensitive parameters. Finally, a fourth additional longer-period planet of mass of 62 +/- 6 M_{\oplus} orbits the star in 1190 days, on an eccentric orbit (e=0.27 +/- 0.11) at a distance of 2.14 +/- 0.27 AU., Comment: Accepted for publication in A&A
- Published
- 2015
19. Characterization of the planetary system Kepler-101 with HARPS-NA hot super-Neptune with an Earth-sized low-mass companion
- Author
-
D. L. Pollacco, M. Lopez-Morales, Courtney D. Dressing, Fatemeh Motalebi, D. Segransan, G. Piotto, Dimitar Sasselov, Andrew Szentgyorgyi, P. Figueira, Francesco Pepe, M. Mayor, S. Gettel, D. Charbonneau, Stéphane Udry, Laura Affer, Alessandro Sozzetti, A. F. M. Fiorenzano, V. Nascimbeni, David F. Phillips, Andrew Collier Cameron, Xavier Dumusque, Keith Horne, Emilio Molinari, Luca Malavolta, C. Lovis, Giuseppina Micela, A. S. Bonomo, Christopher A. Watson, Lars A. Buchhave, R. D. Haywood, A. Harutyunyan, Rosario Cosentino, D. W. Latham, Ken Rice, D. Queloz, Science & Technology Facilities Council, European Commission, PPARC - Now STFC, and University of St Andrews. School of Physics and Astronomy
- Subjects
planetary systems ,stars: fundamental parameters ,techniques: photometric ,techniques: radial velocities ,techniques: spectroscopic ,010504 meteorology & atmospheric sciences ,Star (game theory) ,Astrophysics ,01 natural sciences ,fundamental parameters [Stars] ,spectroscopic [Techniques] ,Planet ,Neptune ,0103 physical sciences ,QB Astronomy ,010303 astronomy & astrophysics ,QC ,0105 earth and related environmental sciences ,QB ,Physics ,radial velocities [Techniques] ,photometric [Techniques] ,Giant planet ,Astronomy and Astrophysics ,Radius ,Planetary system ,Orbit ,Planetary systems ,QC Physics ,13. Climate action ,Space and Planetary Science ,Low Mass - Abstract
We characterize the planetary system Kepler-101 by performing a combined differential evolution Markov chain Monte Carlo analysis of Kepler data and forty radial velocities obtained with the HARPS-N spectrograph. This system was previously validated and is composed of a hot super-Neptune, Kepler-101b, and an Earth-sized planet, Kepler-101c. These two planets orbit the slightly evolved and metal-rich G-type star in 3.49 and 6.03 days, respectively. With mass Mp = 51.1-4.7+ 5.1 M⊕, radius Rp = 5.77-0.79+ 0.85 R⊕, and density ρp = 1.45-0.48+ 0.83 g cm-3, Kepler-101b is the first fully characterized super-Neptune, and its density suggests that heavy elements make up a significant fraction of its interior; more than 60% of its total mass. Kepler-101c has a radius of 1.25-0.17+ 0.19 R⊕, which implies the absence of any H/He envelope, but its mass could not be determined because of the relative faintness of the parent star for highly precise radial-velocity measurements (Kp = 13.8) and the limited number of radial velocities. The 1σ upper limit, Mp
- Published
- 2014
20. Testing the Spectroscopic Extraction of Suppression of Convective Blueshift.
- Author
-
M. Miklos, T. W. Milbourne, R. D. Haywood, D. F. Phillips, S. H. Saar, N. Meunier, H. M. Cegla, X. Dumusque, N. Langellier, J. Maldonado, L. Malavolta, A. Mortier, S. Thompson, C. A. Watson, M. Cecconi, R. Cosentino, A. Ghedina, C-H. Li, M. López-Morales, and E. Molinari
- Subjects
ATOMIC spectra ,SPECTRAL line formation ,SOLAR photosphere ,STELLAR activity ,SOLAR telescopes ,PLANETARY orbits ,TIME series analysis - Abstract
Efforts to detect low-mass exoplanets using stellar radial velocities (RVs) are currently limited by magnetic photospheric activity. Suppression of convective blueshift is the dominant magnetic contribution to RV variability in low-activity Sun-like stars. Due to convective plasma motion, the magnitude of RV contributions from the suppression of convective blueshift is related to the depth of formation of photospheric spectral lines for a given species used to compute the RV time series. Meunier et al. used this relation to demonstrate a method for spectroscopic extraction of the suppression of convective blueshift in order to isolate RV contributions, including planetary RVs, that contribute equally to the time series for each spectral line. Here, we extract disk-integrated solar RVs from observations over a 2.5 yr time span made with the solar telescope integrated with the HARPS-N spectrograph at the Telescopio Nazionale Galileo (La Palma, Canary Islands, Spain). We apply the methods outlined by Meunier et al. We are not, however, able to isolate physically meaningful contributions due to the suppression of convective blueshift from this solar data set, potentially because our data set is taken during solar minimum when the suppression of convective blueshift may not sufficiently dominate activity contributions to RVs. This result indicates that, for low-activity Sun-like stars, one must include additional RV contributions from activity sources not considered in the Meunier et al. model at different timescales, as well as instrumental variation, in order to reach the submeter per second RV sensitivity necessary to detect low-mass planets in orbit around Sun-like stars. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
21. HARPS-N Solar RVs Are Dominated by Large, Bright Magnetic Regions.
- Author
-
T. W. Milbourne, R. D. Haywood, D. F. Phillips, S. H. Saar, H. M. Cegla, A. C. Cameron, J. Costes, X. Dumusque, N. Langellier, D. W. Latham, J. Maldonado, L. Malavolta, A. Mortier, M. L. Palumbo III, S. Thompson, C. A. Watson, F. Bouchy, N. Buchschacher, M. Cecconi, and D. Charbonneau
- Subjects
- *
STELLAR activity , *SOLAR spectra , *SOLAR telescopes , *HELIOSEISMOLOGY , *SOLAR radiation , *LIGHT curves - Abstract
State-of-the-art radial-velocity (RV) exoplanet searches are currently limited by RV signals arising from stellar magnetic activity. We analyze solar observations acquired over a 3 yr period during the decline of Carrington Cycle 24 to test models of RV variation of Sun-like stars. A purpose-built solar telescope at the High Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) provides disk-integrated solar spectra, from which we extract RVs and . The Solar Dynamics Observatory (SDO) provides disk-resolved images of magnetic activity. The Solar Radiation and Climate Experiment (SORCE) provides near-continuous solar photometry, analogous to a Kepler light curve. We verify that the SORCE photometry and HARPS-N correlate strongly with the SDO-derived magnetic filling factor, while the HARPS-N RV variations do not. To explain this discrepancy, we test existing models of RV variations. We estimate the contributions of the suppression of convective blueshift and the rotational imbalance due to brightness inhomogeneities to the observed HARPS-N RVs. We investigate the time variation of these contributions over several rotation periods, and how these contributions depend on the area of active regions. We find that magnetic active regions smaller than 60 Mm2 do not significantly suppress convective blueshift. Our area-dependent model reduces the amplitude of activity-induced RV variations by a factor of two. The present study highlights the need to identify a proxy that correlates specifically with large, bright magnetic regions on the surfaces of exoplanet-hosting stars. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
22. Stellar Surface Magneto-convection as a Source of Astrophysical Noise. II. Center-to-limb Parameterization of Absorption Line Profiles and Comparison to Observations.
- Author
-
H. M. Cegla, C. A. Watson, S. Shelyag, W. J. Chaplin, G. R. Davies, M. Mathioudakis, M. L. Palumbo III, S. H. Saar, and R. D. Haywood
- Subjects
STELLAR activity ,ASTROPHYSICS research ,SPECTROSCOPIC light sources ,RADIAL velocity of galaxies ,MAGNETOHYDRODYNAMICS ,PLASMA flow - Abstract
Manifestations of stellar activity (such as star-spots, plage/faculae, and convective flows) are well-known to induce spectroscopic signals often referred to as astrophysical noise by exoplanet hunters. For example, setting an ultimate goal of detecting true Earth analogs demands reaching radial velocity (RV) precisions of ∼9 cm s
−1 . While this is becoming technically feasible with the latest generation of highly stabilized spectrographs, it is astrophysical noise that sets the true fundamental barrier on attainable RV precisions. In this paper, we parameterize the impact of solar surface magneto-convection on absorption line profiles, and extend the analysis from the solar disk center (Paper I) to the solar limb. Off disk-center, the plasma flows orthogonal to the granule tops begin to lie along the line of sight, and those parallel to the granule tops are no longer completely aligned with the observer. Moreover, the granulation is corrugated and the granules can block other granules, as well as the intergranular lane components. Overall, the visible plasma flows and geometry of the corrugated surface significantly impact the resultant line profiles and induce center-to-limb variations in shape and net position. We detail these herein, and compare to various solar observations. We find our granulation parameterization can recreate realistic line profiles and induced radial velocity shifts, across the stellar disk, indicative of both those found in computationally heavy radiative 3D magnetohydrodynamical simulations and empirical solar observations. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.