Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass
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 _⊕ , an...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/acca1c |
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| 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 Lars A. Buchhave |
| author_facet | 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 Lars A. Buchhave |
| author_sort | Andrew W. Mayo |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-03-12T03:27:28Z |
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| id | doaj.art-ef26940b7ac64f7381c53d144cc59772 |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-03-12T03:27:28Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-ef26940b7ac64f7381c53d144cc597722023-09-03T13:34:26ZengIOP PublishingThe Astronomical Journal1538-38812023-01-01165623510.3847/1538-3881/acca1cHyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured MassAndrew W. Mayo0https://orcid.org/0000-0002-7216-2135Courtney D. Dressing1https://orcid.org/0000-0001-8189-0233Andrew Vanderburg2https://orcid.org/0000-0001-7246-5438Charles D. Fortenbach3https://orcid.org/0000-0001-5286-639XFlorian Lienhard4https://orcid.org/0000-0003-4047-0771Luca Malavolta5https://orcid.org/0000-0002-6492-2085Annelies Mortier6https://orcid.org/0000-0001-7254-4363Alejandro Núñez7https://orcid.org/0000-0002-8047-1982Tyler Richey-Yowell8https://orcid.org/0000-0003-1290-3621Emma V. Turtelboom9https://orcid.org/0000-0002-1845-2617Aldo S. Bonomo10https://orcid.org/0000-0002-6177-198XDavid W. Latham11https://orcid.org/0000-0001-9911-7388Mercedes López-Morales12https://orcid.org/0000-0003-3204-8183Evgenya Shkolnik13https://orcid.org/0000-0002-7260-5821Alessandro Sozzetti14https://orcid.org/0000-0002-7504-365XMarcel A. Agüeros15https://orcid.org/0000-0001-7077-3664Luca Borsato16https://orcid.org/0000-0003-4047-0771David Charbonneau17https://orcid.org/0000-0002-9003-484XRosario Cosentino18https://orcid.org/0000-0003-1784-1431Stephanie T. Douglas19https://orcid.org/0000-0001-7371-2832Xavier Dumusque20https://orcid.org/0000-0002-9332-2011Adriano Ghedina21https://orcid.org/0000-0003-4702-5152Rose Gibson22Valentina Granata23https://orcid.org/0000-0002-1425-4541Avet Harutyunyan24R. D. Haywood25https://orcid.org/0000-0001-9140-3574Gaia Lacedelli26https://orcid.org/0000-0002-4197-7374Vania Lorenzi27https://orcid.org/0000-0002-1958-9930Antonio Magazzù28https://orcid.org/0000-0003-1259-4371A. F. Martinez Fiorenzano29https://orcid.org/0000-0002-4272-4272Giuseppina Micela30https://orcid.org/0000-0002-9900-4751Emilio Molinari31https://orcid.org/0000-0002-1742-7735Marco Montalto32https://orcid.org/0000-0002-7618-8308Domenico Nardiello33https://orcid.org/0000-0003-1149-3659Valerio Nascimbeni34https://orcid.org/0000-0001-9770-1214Isabella Pagano35https://orcid.org/0000-0001-9573-4928Giampaolo Piotto36https://orcid.org/0000-0002-9937-6387Lorenzo Pino37https://orcid.org/0000-0002-1321-8856Ennio Poretti38https://orcid.org/0000-0003-1200-0473Gaetano Scandariato39https://orcid.org/0000-0003-2029-0626Stephane Udry40https://orcid.org/0000-0001-7576-6236Lars A. Buchhave41https://orcid.org/0000-0003-1605-5666Astronomy Department, University of California , Berkeley, CA 94720, USA ; mayo@berkeley.edu; Centre for Star and Planet Formation, Natural History Museum of Denmark & Niels Bohr Institute, University of Copenhagen , Øster Voldgade 5-7, DK-1350 Copenhagen K., DenmarkAstronomy Department, University of California , Berkeley, CA 94720, USA ; mayo@berkeley.eduDepartment of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USADepartment of Physics and Astronomy, San Francisco State University , San Francisco, CA 94132, USAAstrophysics Group, Cavendish Laboratory, University of Cambridge , J. J. Thomson Avenue, Cambridge CB3 0HE, UKDipartimento di Fisica e Astronomia Galileo Galilei, Universitá di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, ItalyAstrophysics Group, Cavendish Laboratory, University of Cambridge , J. J. Thomson Avenue, Cambridge CB3 0HE, UK; School of Physics & Astronomy, University of Birmingham , Edgbaston, Birmingham, B15 2TT, UK; Kavli Institute for Cosmology, University of Cambridge , Madingley Road, Cambridge CB3 0HA, UKDepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USASchool of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287, USAAstronomy Department, University of California , Berkeley, CA 94720, USA ; mayo@berkeley.eduINAF—Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, ItalyCenter for Astrophysics ∣ Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USACenter for Astrophysics ∣ Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USASchool of Earth and Space Exploration, Arizona State University , Tempe, AZ 85287, USAINAF—Osservatorio Astrofisico di Torino, Via Osservatorio 20, I-10025 Pino Torinese, ItalyLaboratoire d’astrophysique de Bordeaux, Univ. Bordeaux , CNRS, B18N, Allée Geoffroy Saint-Hilaire, F-33615 Pessac, France; Department of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USAINAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, ItalyCenter for Astrophysics ∣ Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USAFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, SpainDepartment of Physics, Lafayette College, 730 High Street, Easton, PA 18042, USADepartment of Astronomy of the University of Geneva, Geneva Observatory, Chemin Pegasi 51, 1290 Versoix, SwitzerlandFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, SpainColumbia University , Department of Astronomy, 550 West 120th Street, New York, NY 10027, USADipartimento di Fisica e Astronomia Galileo Galilei, Universitá di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy; INAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, ItalyFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, SpainAstrophysics Group, University of Exeter , Exeter EX4 2QL, UKDipartimento di Fisica e Astronomia Galileo Galilei, Universitá di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy; INAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, ItalyFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, Spain; Instituto de Astrofísica de Canarias, C/Vía Láctea s/n, E-38205 La Laguna, SpainFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, SpainFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, SpainINAF—Osservatorio Astronomico di Palermo , Piazza del Parlamento 1, I-90134 Palermo, ItalyINAF—Osservatorio Astronomico di Cagliari & REM , Via della Scienza, 5, I-09047 Selargius CA, ItalyDipartimento di Fisica e Astronomia Galileo Galilei, Universitá di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy; INAF—Osservatorio Astrofisico di Catania , Via Santa Sofia 78, I-95123 Catania, ItalyINAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, Italy; Aix Marseille Univ , CNRS, CNES, LAM, Marseille, FranceINAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, ItalyINAF—Osservatorio Astrofisico di Catania , Via Santa Sofia 78, I-95123 Catania, ItalyDipartimento di Fisica e Astronomia Galileo Galilei, Universitá di Padova , Vicolo dell’Osservatorio 3, I-35122 Padova, Italy; INAF—Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova, ItalyINAF—Osservatorio Astrofisico di Arcetri , Largo Enrico Fermi 5, I-50125, Firenze, ItalyFundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, E-38712 Breña Baja, Tenerife, Spain; INAF—Osservatorio Astronomico di Brera , Via E. Bianchi 46, I-23807 Merate, ItalyAix Marseille Univ , CNRS, CNES, LAM, Marseille, FranceDepartment of Physics, Lafayette College, 730 High Street, Easton, PA 18042, USACentre for Star and Planet Formation, Natural History Museum of Denmark & Niels Bohr Institute, University of Copenhagen , Øster Voldgade 5-7, DK-1350 Copenhagen K., Denmark; DTU Space, National Space Institute, Technical University of Denmark , Elektrovej 327, DK-2800 Lyngby, DenmarkK2-136 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.https://doi.org/10.3847/1538-3881/acca1cExoplanetsExoplanet systemsExoplanet atmospheresExoplanet detection methodsRadial velocityTransits |
| spellingShingle | 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 Lars A. Buchhave Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass The Astronomical Journal Exoplanets Exoplanet systems Exoplanet atmospheres Exoplanet detection methods Radial velocity Transits |
| title | Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass |
| title_full | Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass |
| title_fullStr | Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass |
| title_full_unstemmed | Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass |
| title_short | Hyades Member K2-136c: The Smallest Planet in an Open Cluster with a Precisely Measured Mass |
| title_sort | hyades member k2 136c the smallest planet in an open cluster with a precisely measured mass |
| topic | Exoplanets Exoplanet systems Exoplanet atmospheres Exoplanet detection methods Radial velocity Transits |
| url | https://doi.org/10.3847/1538-3881/acca1c |
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