Zodiacal Exoplanets in Time (ZEIT). VII. A Temperate Candidate Super-Earth in the Hyades Cluster

Transiting exoplanets in young open clusters present opportunities to study how exoplanets evolve over their lifetimes. Recently, significant progress detecting transiting planets in young open clusters has been made with the K2 mission, but so far all of these transiting cluster planets orbit close to their host stars, so planet evolution can only be studied in a high-irradiation regime. Here, we report the discovery of a long-period planet candidate, called HD 283869 b, orbiting a member of the Hyades cluster. Using data from the K2 mission, we detected a single transit of a super-Earth-sized (1.96 +/- 0.12 R_earth) planet candidate orbiting the K-dwarf HD 283869 with a period longer than 72 days. Since we only detected a single transit event, we cannot validate HD 283869 b with high confidence, but our analysis of the K2 images, archival data, and follow-up observations suggests that the source of the event is indeed a transiting planet. We estimated the candidate's orbital parameters and find that if real, it has a period P~100 days and receives approximately Earth-like incident flux, giving the candidate a 71% chance of falling within the circumstellar habitable zone. If confirmed, HD 283869 b would have the longest orbital period, lowest incident flux, and brightest host star of any known transiting planet in an open cluster, making it uniquely important to future studies of how stellar irradiation affects planetary evolution.

[1]  H. Shapley Studies based on the colors and magnitudes in stellar clusters. I,II,III. , 1917 .

[2]  Otto Struve,et al.  Proposal for a project of high-precision stellar radial velocity work , 1952 .

[3]  G. Walker,et al.  PRECISION RADIAL VELOCITIES WITH AN ABSORPTION CELL. , 1979 .

[4]  J. Underwood,et al.  Stellar coronae in the Hyades - A soft X-ray survey with the Einstein Observatory , 1981 .

[5]  J. Gunn,et al.  A radial-velocity survey of the Hyades , 1988 .

[6]  Gordon A. H. Walker,et al.  A search for substellar companions to solar-type stars , 1988 .

[7]  T. Mazeh,et al.  The unseen companion of HD114762: a probable brown dwarf , 1989, Nature.

[8]  Todd J. Henry,et al.  The mass-luminosity relation for stars of mass 1.0 to 0.08 solar mass , 1993 .

[9]  M. Mayor,et al.  A Jupiter-mass companion to a solar-type star , 1995, Nature.

[10]  A. Boss Proximity of Jupiter-Like Planets to Low-Mass Stars , 1995, Science.

[11]  B. W.,et al.  THE DISCOVERY OF A PLANETARY COMPANION TO 16 CYGNI B , 1996 .

[12]  M. A. C. Perryman,et al.  The Hipparcos and Tycho catalogues : astrometric and photometric star catalogues derived from the ESA Hipparcos Space Astrometry Mission , 1997 .

[13]  W. D. Cochran,et al.  The Discovery of a Planetary Companion to 16 Cygni B , 1997 .

[14]  R. Paul Butler,et al.  Three New “51 Pegasi-Type” Planets , 1997 .

[15]  J.-C. Mermilliod,et al.  The General Catalogue of Photometric Data (GCPD). II. , 1997 .

[16]  David Charbonneau,et al.  A Lack of Planets in 47 Tucanae from a Hubble Space Telescope Search , 2000 .

[17]  J. Beuzit,et al.  HD 80606 b, a planet on an extremely elongated orbit , 2001, astro-ph/0106256.

[18]  William D. Cochran,et al.  Searching for Planets in the Hyades. I. The Keck Radial Velocity Survey , 2002, astro-ph/0204215.

[19]  E. Agol,et al.  Analytic Light Curves for Planetary Transit Searches , 2002, astro-ph/0210099.

[20]  G. Kov'acs,et al.  A box-fitting algorithm in the search for periodic transits , 2002, astro-ph/0206099.

[21]  F. Crifo,et al.  3D mapping of the dense interstellar gas around the Local Bubble , 2003 .

[22]  W. Cochran,et al.  Searching for Planets in the Hyades. IV. Differential Abundance Analysis of Hyades Dwarfs , 2003 .

[23]  Wm. A. Wheaton,et al.  Spectral Irradiance Calibration in the Infrared. XIV. The Absolute Calibration of 2MASS , 2003, astro-ph/0304350.

[24]  W. D. Cochran,et al.  SEARCHING FOR PLANETS IN THE HYADES. V. LIMITS ON PLANET DETECTION IN THE PRESENCE OF STELLAR ACTIVITY , 2004 .

[25]  John T. Rayner,et al.  An Infrared Spectroscopic Sequence of M, L, and T Dwarfs , 2004, astro-ph/0412313.

[26]  B. Scott Gaudi,et al.  Fraction of Stars With Planets in the Open Cluster NGC 1245 , 2004 .

[27]  M. Skrutskie,et al.  The Two Micron All Sky Survey (2MASS) , 2006 .

[28]  A Photometric Survey for Variables and Transits in the Field of Praesepe with KELT , 2007, 0709.2728.

[29]  S. Barnes Accepted for publication in The Astrophysical Journal Ages for illustrative field stars using gyrochronology: viability, limitations and errors , 2022 .

[30]  Michitoshi Yoshida,et al.  A Planetary Companion to the Hyades Giant ϵ Tauri , 2007 .

[31]  M. Mayor,et al.  Planets around evolved intermediate-mass stars - I. Two substellar companions in the open clusters NGC 2423 and NGC 4349 , 2007, 0706.2174.

[32]  L. Hillenbrand,et al.  Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics , 2008, 0807.1686.

[33]  Darko Jevremovic,et al.  The Dartmouth Stellar Evolution Database , 2008, 0804.4473.

[34]  J. Pepper,et al.  A PHOTOMETRIC SURVEY FOR VARIABLES AND TRANSITS IN THE FIELD OF PRAESEPE WITH THE KILODEGREE EXTREMELY LITTLE TELESCOPE , 2008 .

[35]  S. Udry,et al.  Catalogues of radial and rotational velocities of 1253 F–K dwarfs in 13 nearby open clusters , 2009 .

[36]  W. D. Vacca,et al.  THE INFRARED TELESCOPE FACILITY (IRTF) SPECTRAL LIBRARY: COOL STARS , 2009, 0909.0818.

[37]  Xavier Bonfils,et al.  A super-Earth transiting a nearby low-mass star , 2009, Nature.

[38]  Jonathan R Goodman,et al.  Ensemble samplers with affine invariance , 2010 .

[39]  G. Furesz,et al.  HAT-P-16b: A 4 MJ PLANET TRANSITING A BRIGHT STAR ON AN ECCENTRIC ORBIT, , 2010, 1005.2009.

[40]  Martin G. Cohen,et al.  THE WIDE-FIELD INFRARED SURVEY EXPLORER (WISE): MISSION DESCRIPTION AND INITIAL ON-ORBIT PERFORMANCE , 2010, 1008.0031.

[41]  Berkeley,et al.  THE FACTORY AND THE BEEHIVE. I. ROTATION PERIODS FOR LOW-MASS STARS IN PRAESEPE , 2011, 1107.4039.

[42]  E. Schilbach,et al.  A deep all-sky census of the Hyades , 2011, 1105.6093.

[43]  D. Ciardi,et al.  SPECKLE CAMERA OBSERVATIONS FOR THE NASA KEPLER MISSION FOLLOW-UP PROGRAM , 2011 .

[44]  S. Bloemen,et al.  Gravity and limb-darkening coefficients for the Kepler, CoRoT, Spitzer, uvby, UBVRIJHK, and Sloan photometric systems , 2011 .

[45]  M. Ireland,et al.  Multidimensional Bayesian membership analysis of the Sco OB2 moving group , 2011, 1106.2857.

[46]  B. Gaudi,et al.  ENSEMBLE ANALYSIS OF OPEN CLUSTER TRANSIT SURVEYS: UPPER LIMITS ON THE FREQUENCY OF SHORT-PERIOD PLANETS CONSISTENT WITH THE FIELD , 2010, 1009.3013.

[47]  Robert D. Mathieu,et al.  A mass transfer origin for blue stragglers in NGC 188 as revealed by half-solar-mass companions , 2011, Nature.

[48]  S. E. Dahm,et al.  TWO “b”s IN THE BEEHIVE: THE DISCOVERY OF THE FIRST HOT JUPITERS IN AN OPEN CLUSTER , 2012, 1207.0818.

[49]  J. B. Laird,et al.  An abundance of small exoplanets around stars with a wide range of metallicities , 2012, Nature.

[50]  J. Johnson,et al.  THE PHOTOECCENTRIC EFFECT AND PROTO-HOT JUPITERS. III. A PAUCITY OF PROTO-HOT JUPITERS ON SUPER-ECCENTRIC ORBITS , 2012, 1211.0554.

[51]  Michael S. Bessell,et al.  Spectrophotometric Libraries, Revised Photonic Passbands, and Zero Points for UBVRI, Hipparcos, and Tycho Photometry , 2011, 1112.2698.

[52]  Paul M. Brunet,et al.  The Gaia mission , 2013, 1303.0303.

[53]  H. Müller,et al.  High-precision stellar limb-darkening measurements - A transit study of 38 Kepler planetary candidates , 2013 .

[54]  Ryan C. Terrien,et al.  HABITABLE ZONES AROUND MAIN-SEQUENCE STARS: NEW ESTIMATES , 2013, 1301.6674.

[55]  David M. Kipping,et al.  Parametrizing the exoplanet eccentricity distribution with the beta distribution. , 2013, 1306.4982.

[56]  Howard Isaacson,et al.  The same frequency of planets inside and outside open clusters of stars , 2013, Nature.

[57]  D. James,et al.  Trumpeting M dwarfs with CONCH-SHELL: a catalogue of nearby cool host-stars for habitable exoplanets and life , 2014, 1406.7353.

[58]  J. Fortney,et al.  UNDERSTANDING THE MASS–RADIUS RELATION FOR SUB-NEPTUNES: RADIUS AS A PROXY FOR COMPOSITION , 2013, 1311.0329.

[59]  A. Vanderburg Reduced Light Curves from Campaign 0 of the K2 Mission , 2014, 1412.1827.

[60]  D. Kipping Bayesian priors for the eccentricity of transiting planets , 2014, 1408.1393.

[61]  L. Rogers MOST 1.6 EARTH-RADIUS PLANETS ARE NOT ROCKY , 2014, 1407.4457.

[62]  L. Buchhave,et al.  Three regimes of extrasolar planet radius inferred from host star metallicities , 2014, Nature.

[63]  J. Bochanski,et al.  THE FACTORY AND THE BEEHIVE. II. ACTIVITY AND ROTATION IN PRAESEPE AND THE HYADES , 2014, 1409.7603.

[64]  Kento Masuda,et al.  VERY LOW DENSITY PLANETS AROUND KEPLER-51 REVEALED WITH TRANSIT TIMING VARIATIONS AND AN ANOMALY SIMILAR TO A PLANET–PLANET ECLIPSE EVENT , 2014, 1401.2885.

[65]  F. Mullally,et al.  The K2 Mission: Characterization and Early Results , 2014, 1402.5163.

[66]  Mark Clampin,et al.  Transiting Exoplanet Survey Satellite , 2014, 1406.0151.

[67]  E. Agol,et al.  VALIDATION OF KEPLER'S MULTIPLE PLANET CANDIDATES. III. LIGHT CURVE ANALYSIS AND ANNOUNCEMENT OF HUNDREDS OF NEW MULTI-PLANET SYSTEMS , 2014, 1402.6534.

[68]  A. Vanderburg,et al.  A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission , 2014, 1408.3853.

[69]  D. Evans,et al.  The CMC15, the last issue of the series “Carlsberg Meridian Catalogue, La Palma” , 2014 .

[70]  A. Collier Cameron,et al.  Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system , 2013, Proceedings of the International Astronomical Union.

[71]  Jaymie M. Matthews,et al.  CHARACTERIZING K2 PLANET DISCOVERIES: A SUPER-EARTH TRANSITING THE BRIGHT K DWARF HIP 116454 , 2014, 1412.5674.

[72]  Adam L. Kraus,et al.  ZODIACAL EXOPLANETS IN TIME (ZEIT). I. A NEPTUNE-SIZED PLANET ORBITING AN M4.5 DWARF IN THE HYADES STAR CLUSTER , 2015, 1512.00483.

[73]  M. R. Haas,et al.  THE K2 ECLIPTIC PLANE INPUT CATALOG (EPIC) AND STELLAR CLASSIFICATIONS OF 138,600 TARGETS IN CAMPAIGNS 1–8 , 2015, 1512.02643.

[74]  P. Berlind,et al.  PLANETARY CANDIDATES FROM THE FIRST YEAR OF THE K2 MISSION , 2015, 1511.07820.

[75]  A. Mann,et al.  Revised Filter Profiles and Zero Points for Broadband Photometry , 2014, 1412.1474.

[76]  K. Braun,et al.  HOW TO CONSTRAIN YOUR M DWARF: MEASURING EFFECTIVE TEMPERATURE, BOLOMETRIC LUMINOSITY, MASS, AND RADIUS , 2015, 1501.01635.

[77]  Eric B. Ford,et al.  PROBABILISTIC MASS–RADIUS RELATIONSHIP FOR SUB-NEPTUNE-SIZED PLANETS , 2015, 1504.07557.

[78]  Timothy D. Brandt,et al.  THE AGE AND AGE SPREAD OF THE PRAESEPE AND HYADES CLUSTERS: A CONSISTENT, ∼800 Myr PICTURE FROM ROTATING STELLAR MODELS , 2015, 1504.00004.

[79]  M. Ireland,et al.  New pre-main-sequence stars in the Upper Scorpius subgroup of Sco–Cen , 2015, 1501.07270.

[80]  Aaron Dotter,et al.  MESA ISOCHRONES AND STELLAR TRACKS (MIST) 0: METHODS FOR THE CONSTRUCTION OF STELLAR ISOCHRONES , 2016, 1601.05144.

[81]  Jeffrey E. Van Cleve,et al.  Kepler Instrument Handbook , 2016 .

[82]  S. Hinkley,et al.  A Neptune-sized transiting planet closely orbiting a 5–10-million-year-old star , 2016, Nature.

[83]  J. Meléndez,et al.  The Hyades open cluster is chemically inhomogeneous , 2016, 1601.07354.

[84]  G. Piotto,et al.  A PSF-based approach to Kepler/K2 data – II. Exoplanet candidates in Praesepe (M 44) , 2016, 1608.00459.

[85]  M. R. Haas,et al.  FALSE POSITIVE PROBABILITIES FOR ALL KEPLER OBJECTS OF INTEREST: 1284 NEWLY VALIDATED PLANETS AND 428 LIKELY FALSE POSITIVES , 2016, 1605.02825.

[86]  Adam L. Kraus,et al.  ZODIACAL EXOPLANETS IN TIME (ZEIT). IV. SEVEN TRANSITING PLANETS IN THE PRAESEPE CLUSTER , 2016, 1609.00726.

[87]  Michael C. Liu,et al.  K2 DISCOVERS A BUSY BEE: AN UNUSUAL TRANSITING NEPTUNE FOUND IN THE BEEHIVE CLUSTER , 2016, 1608.04760.

[88]  K. Stassun,et al.  NEW PLEIADES ECLIPSING BINARIES AND A HYADES TRANSITING SYSTEM IDENTIFIED BY K2 , 2016, 1602.01901.

[89]  Christoph Baranec,et al.  FIVE PLANETS TRANSITING A NINTH MAGNITUDE STAR , 2016, 1606.08441.

[90]  Observatoire de la Côte d'Azur,et al.  Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties , 2016, 1609.04172.

[91]  A. Vanderburg,et al.  THE K2 M67 STUDY: AN EVOLVED BLUE STRAGGLER IN M67 FROM K2 MISSION ASTEROSEISMOLOGY , 2016, 1611.01158.

[92]  Jieun Choi,et al.  MESA ISOCHRONES AND STELLAR TRACKS (MIST). I. SOLAR-SCALED MODELS , 2016, 1604.08592.

[93]  L. Dutra-Ferreira,et al.  Consistent metallicity scale for cool dwarfs and giants. A benchmark test using the Hyades , 2015, 1509.07725.

[94]  Gaia Collaboration,et al.  The Gaia mission , 2016, 1609.04153.

[95]  K. Covey,et al.  K2 ROTATION PERIODS FOR LOW-MASS HYADS AND THE IMPLICATIONS FOR GYROCHRONOLOGY , 2016, 1603.00419.

[96]  Marshall C. Johnson,et al.  ZODIACAL EXOPLANETS IN TIME (ZEIT). III. A SHORT-PERIOD PLANET ORBITING A PRE-MAIN-SEQUENCE STAR IN THE UPPER SCORPIUS OB ASSOCIATION , 2016, 1604.06165.

[97]  Ulrich Bastian,et al.  Hot Stuff for One Year (HSOY) - A 583 million star proper motion catalogue derived from Gaia DR1 and PPMXL , 2017, 1701.02629.

[98]  J. Winn,et al.  Reassessment of the Null Result of the HST Search for Planets in 47 Tucanae , 2017, 1703.06136.

[99]  K. Covey,et al.  Poking the Beehive from Space: K2 Rotation Periods for Praesepe , 2017, 1704.04507.

[100]  M. Tamura,et al.  Three Small Planets Transiting a Hyades Star , 2017, 1710.07203.

[101]  K. Covey,et al.  Zodiacal Exoplanets in Time (ZEIT). V. A Uniform Search for Transiting Planets in Young Clusters Observed by K2 , 2017, 1709.09670.

[102]  M. Pinsonneault,et al.  Rotation of Late-type Stars in Praesepe with K2 , 2017, 1703.07031.

[103]  Adam L. Kraus,et al.  Zodiacal Exoplanets in Time (ZEIT). VI. A Three-planet System in the Hyades Cluster Including an Earth-sized Planet , 2017, The Astronomical Journal.

[104]  A. D. Feinstein,et al.  K2-136: A Hyades Binary Star with a Neptune-sized Planet , 2017, 1709.10398.

[105]  A. D. Feinstein,et al.  K2-136: A Binary System in the Hyades Cluster Hosting a Neptune-sized Planet , 2017 .

[106]  Joshua N. Winn,et al.  Planet Detection Simulations for Several Possible TESS Extended Missions , 2017, 1705.08891.

[107]  T. A. Lister,et al.  Gaia Data Release 2. Summary of the contents and survey properties , 2018, 1804.09365.

[108]  V. B'ejar,et al.  The Lithium Depletion Boundary and the Age of the Hyades Cluster , 2018, 1802.07155.

[109]  Clea F. Schumer,et al.  275 Candidates and 149 Validated Planets Orbiting Bright Stars in K2 Campaigns 0–10 , 2018, 1802.05277.

[110]  Jason T. Wright,et al.  K2-231 b: A Sub-Neptune Exoplanet Transiting a Solar Twin in Ruprecht 147 , 2018, 1803.07430.

[111]  Keivan G. Stassun,et al.  The TESS Input Catalog and Candidate Target List , 2017, The Astronomical Journal.

[112]  M. Ygouf,et al.  Discovery of a Transiting Adolescent Sub-Neptune Exoplanet in the Cas-Tau Association with K2 , 2018 .