K2-263 b: A 50 d period sub-Neptune with a mass measurement using HARPS-N

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; S. Udry

doi:10.1093/MNRAS/STY2360

K2-263 b: A 50 d period sub-Neptune with a mass measurement using HARPS-N

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. HaywoodJ. 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, S. Udry

^*Corresponding author for this work

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

10 Citations (Scopus)

Abstract

This paper reports on the validation and mass measurement of K2-263 b, a sub-Neptune orbiting a quiet G9V star. Using K2 data from campaigns C5 and C16, we find this planet to have a period of 50.818947 ± 0.000094 d and a radius of 2.41 ± 0.12 R_⊕. We followed this system with HARPS-N to obtain 67 precise radial velocities (RVs). A combined fit of the transit and radial velocity data reveals that K2-263 b has a mass of 14.8 ± 3.1M_⊕. Its bulk density (5.7_-1.4 ^+1.6 g cm^-3) implies that this planet has a significant envelope of water or other volatiles around a rocky core. K2-263 b likely formed in a similar way as the cores of the four giant planets in our own Solar System, but for some reason, did not accrete much gas. The planetary mass was confirmed by an independent Gaussian process-based fit to both the RVs and the spectroscopic activity indicators. K2-263 b belongs to only a handful of confirmed K2 exoplanets with periods longer than 40 d. It is among the longest periods for a small planet with a precisely determined mass using RVs.

Original language	English
Pages (from-to)	1839-1847
Number of pages	9
Journal	Monthly Notices of the Royal Astronomical Society
Volume	481
Issue number	2
DOIs	https://doi.org/10.1093/MNRAS/STY2360
Publication status	Published - 1 Dec 2018

Bibliographical note

Funding Information:
This material is based upon work supported by the National Aeronautics and Space Administration (NASA) under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, NASA’s Astrophysics Data System and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the In-stituto de Astrofisica de Canarias. This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. K2-263 was observed as part of the following Guest Programmes: GO5007 LC (PI: Winn), GO5029 LC (PI: Charbonneau), GO5033 LC (PI: Howard), GO5104 LC (PI: Dragomir), GO5106 LC (PI: Jackson), GO5060 LC (PI: Coughlin), GO16009 LC (PI: Char-bonneau), GO16011 LC (PI: Fabrycky), GO16015 LC (PI: Boyajian), GO16020 LC (PI: Adams), GO16021 LC (PI: Howard), GO16101 LC (PI: Winn), GO16009 SC (PI: Char-bonneau), GO16015 SC (PI: Boyajian), and GO16101 SC (PI: Winn).

Funding Information:
We thank the anonymous referee for a prompt report. The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen's University Belfast, and the University of Edinburgh. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH). VMR acknowledges the Royal Astronomical Society and Emmanuel College, Cambridge, for financial support. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (AV, RDH). LM acknowledges the support by INAF/Frontiera through the 'Progetti Premiali' funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithsonian Astrophysical Observatory. CAW acknowledges support by STFC grant ST/P000312/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. This publication was made possible through the support of a grant from the John Templeton Foundation. The opinions expressed are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This material is based upon work supported by the National Aeronautics and Space Administration (NASA) under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, NASA's Astrophysics Data System and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. K2-263 was observed as part of the following Guest Programmes: GO5007 LC (PI: Winn), GO5029 LC (PI: Charbonneau), GO5033 LC (PI: Howard), GO5104 LC (PI: Dragomir), GO5106 LC (PI: Jackson), GO5060 LC (PI: Coughlin), GO16009 LC (PI: Charbonneau), GO16011 LC (PI: Fabrycky), GO16015 LC (PI: Boyajian), GO16020 LC (PI: Adams), GO16021 LC (PI: Howard), GO16101 LC (PI: Winn), GO16009 SC (PI: Charbonneau), GO16015 SC (PI: Boyajian), and GO16101 SC (PI: Winn).

Funding Information:
The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH). VMR acknowledges the Royal Astronomical Society and Emmanuel College, Cambridge, for financial support. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (AV, RDH). LM acknowledges the support by INAF/Frontiera through the ‘Progetti Premiali’ funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithso-nian Astrophysical Observatory. CAW acknowledges support by STFC grant ST/P000312/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. This publication was made possible through the support of a grant from the John Temple-ton Foundation. The opinions expressed are those of the authors and do not necessarily reflect the views of the John Templeton Foundation.

Funding Information:
The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen’s University Belfast, and the University of Edinburgh.

Publisher Copyright:
© 2018 The Author(s).

Keywords

Planets and satellites: individual: K2-263b
Techniques: photometric
Techniques: radial velocities
Techniques: spectroscopic

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1093/MNRAS/STY2360

Cite this

Mortier, A., Bonomo, A. S., Rajpaul, V. M., Buchhave, L. A., Vanderburg, A., Zeng, L., López-Morales, M., Malavolta, L., Collier Cameron, A., Dressing, C. D., Figueira, P., Nascimbeni, V., Rice, K., Sozzetti, A., Watson, C., Affer, L., Bouchy, F., Charbonneau, D., Harutyunyan, A., ... Udry, S. (2018). K2-263 b: A 50 d period sub-Neptune with a mass measurement using HARPS-N. Monthly Notices of the Royal Astronomical Society, 481(2), 1839-1847. https://doi.org/10.1093/MNRAS/STY2360

@article{888ba45d7da14fbfb3e2992730198502,

title = "K2-263 b: A 50 d period sub-Neptune with a mass measurement using HARPS-N",

abstract = "This paper reports on the validation and mass measurement of K2-263 b, a sub-Neptune orbiting a quiet G9V star. Using K2 data from campaigns C5 and C16, we find this planet to have a period of 50.818947 ± 0.000094 d and a radius of 2.41 ± 0.12 R⊕. We followed this system with HARPS-N to obtain 67 precise radial velocities (RVs). A combined fit of the transit and radial velocity data reveals that K2-263 b has a mass of 14.8 ± 3.1M⊕. Its bulk density (5.7-1.4 +1.6 g cm-3) implies that this planet has a significant envelope of water or other volatiles around a rocky core. K2-263 b likely formed in a similar way as the cores of the four giant planets in our own Solar System, but for some reason, did not accrete much gas. The planetary mass was confirmed by an independent Gaussian process-based fit to both the RVs and the spectroscopic activity indicators. K2-263 b belongs to only a handful of confirmed K2 exoplanets with periods longer than 40 d. It is among the longest periods for a small planet with a precisely determined mass using RVs.",

keywords = "Planets and satellites: individual: K2-263b, Techniques: photometric, Techniques: radial velocities, Techniques: spectroscopic",

author = "A. Mortier and Bonomo, {A. S.} and Rajpaul, {V. M.} and Buchhave, {L. A.} and A. Vanderburg and L. Zeng and M. L{\'o}pez-Morales and L. Malavolta and {Collier Cameron}, A. and Dressing, {C. D.} and P. Figueira and V. Nascimbeni and K. Rice and A. Sozzetti and C. Watson and L. Affer and F. Bouchy and D. Charbonneau and A. Harutyunyan and Haywood, {R. D.} and Johnson, {J. A.} and Latham, {D. W.} and C. Lovis and {Martinez Fiorenzano}, {A. F.} and M. Mayor and G. Micela and E. Molinari and F. Motalebi and F. Pepe and G. Piotto and D. Phillips and E. Poretti and D. Sasselov and D. S{\'e}gransan and S. Udry",

note = "Funding Information: This material is based upon work supported by the National Aeronautics and Space Administration (NASA) under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, NASA{\textquoteright}s Astrophysics Data System and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the In-stituto de Astrofisica de Canarias. This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. K2-263 was observed as part of the following Guest Programmes: GO5007 LC (PI: Winn), GO5029 LC (PI: Charbonneau), GO5033 LC (PI: Howard), GO5104 LC (PI: Dragomir), GO5106 LC (PI: Jackson), GO5060 LC (PI: Coughlin), GO16009 LC (PI: Char-bonneau), GO16011 LC (PI: Fabrycky), GO16015 LC (PI: Boyajian), GO16020 LC (PI: Adams), GO16021 LC (PI: Howard), GO16101 LC (PI: Winn), GO16009 SC (PI: Char-bonneau), GO16015 SC (PI: Boyajian), and GO16101 SC (PI: Winn). Funding Information: We thank the anonymous referee for a prompt report. The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen's University Belfast, and the University of Edinburgh. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH). VMR acknowledges the Royal Astronomical Society and Emmanuel College, Cambridge, for financial support. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (AV, RDH). LM acknowledges the support by INAF/Frontiera through the 'Progetti Premiali' funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithsonian Astrophysical Observatory. CAW acknowledges support by STFC grant ST/P000312/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. This publication was made possible through the support of a grant from the John Templeton Foundation. The opinions expressed are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This material is based upon work supported by the National Aeronautics and Space Administration (NASA) under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, NASA's Astrophysics Data System and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. K2-263 was observed as part of the following Guest Programmes: GO5007 LC (PI: Winn), GO5029 LC (PI: Charbonneau), GO5033 LC (PI: Howard), GO5104 LC (PI: Dragomir), GO5106 LC (PI: Jackson), GO5060 LC (PI: Coughlin), GO16009 LC (PI: Charbonneau), GO16011 LC (PI: Fabrycky), GO16015 LC (PI: Boyajian), GO16020 LC (PI: Adams), GO16021 LC (PI: Howard), GO16101 LC (PI: Winn), GO16009 SC (PI: Charbonneau), GO16015 SC (PI: Boyajian), and GO16101 SC (PI: Winn). Funding Information: The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH). VMR acknowledges the Royal Astronomical Society and Emmanuel College, Cambridge, for financial support. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (AV, RDH). LM acknowledges the support by INAF/Frontiera through the {\textquoteleft}Progetti Premiali{\textquoteright} funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithso-nian Astrophysical Observatory. CAW acknowledges support by STFC grant ST/P000312/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. This publication was made possible through the support of a grant from the John Temple-ton Foundation. The opinions expressed are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. Funding Information: The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen{\textquoteright}s University Belfast, and the University of Edinburgh. Publisher Copyright: {\textcopyright} 2018 The Author(s).",

year = "2018",

month = dec,

day = "1",

doi = "10.1093/MNRAS/STY2360",

language = "English",

volume = "481",

pages = "1839--1847",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "SIPRI/Oxford University Press",

number = "2",

}

Mortier, A, Bonomo, AS, Rajpaul, VM, Buchhave, LA, Vanderburg, A, Zeng, L, López-Morales, M, Malavolta, L, Collier Cameron, A, Dressing, CD, Figueira, P, Nascimbeni, V, Rice, K, Sozzetti, A, Watson, C, Affer, L, Bouchy, F, Charbonneau, D, Harutyunyan, A, Haywood, RD, Johnson, JA, Latham, DW, Lovis, C, Martinez Fiorenzano, AF, Mayor, M, Micela, G, Molinari, E, Motalebi, F, Pepe, F, Piotto, G, Phillips, D, Poretti, E, Sasselov, D, Ségransan, D & Udry, S 2018, 'K2-263 b: A 50 d period sub-Neptune with a mass measurement using HARPS-N', Monthly Notices of the Royal Astronomical Society, vol. 481, no. 2, pp. 1839-1847. https://doi.org/10.1093/MNRAS/STY2360

TY - JOUR

T1 - K2-263 b

T2 - A 50 d period sub-Neptune with a mass measurement using HARPS-N

AU - Mortier, A.

AU - Bonomo, A. S.

AU - Rajpaul, V. M.

AU - Buchhave, L. A.

AU - Vanderburg, A.

AU - Zeng, L.

AU - López-Morales, M.

AU - Malavolta, L.

AU - Collier Cameron, A.

AU - Dressing, C. D.

AU - Figueira, P.

AU - Nascimbeni, V.

AU - Rice, K.

AU - Sozzetti, A.

AU - Watson, C.

AU - Affer, L.

AU - Bouchy, F.

AU - Charbonneau, D.

AU - Harutyunyan, A.

AU - Haywood, R. D.

AU - Johnson, J. A.

AU - Latham, D. W.

AU - Lovis, C.

AU - Martinez Fiorenzano, A. F.

AU - Mayor, M.

AU - Micela, G.

AU - Molinari, E.

AU - Motalebi, F.

AU - Pepe, F.

AU - Piotto, G.

AU - Phillips, D.

AU - Poretti, E.

AU - Sasselov, D.

AU - Ségransan, D.

AU - Udry, S.

N1 - Funding Information: This material is based upon work supported by the National Aeronautics and Space Administration (NASA) under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, NASA’s Astrophysics Data System and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the In-stituto de Astrofisica de Canarias. This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. K2-263 was observed as part of the following Guest Programmes: GO5007 LC (PI: Winn), GO5029 LC (PI: Charbonneau), GO5033 LC (PI: Howard), GO5104 LC (PI: Dragomir), GO5106 LC (PI: Jackson), GO5060 LC (PI: Coughlin), GO16009 LC (PI: Char-bonneau), GO16011 LC (PI: Fabrycky), GO16015 LC (PI: Boyajian), GO16020 LC (PI: Adams), GO16021 LC (PI: Howard), GO16101 LC (PI: Winn), GO16009 SC (PI: Char-bonneau), GO16015 SC (PI: Boyajian), and GO16101 SC (PI: Winn). Funding Information: We thank the anonymous referee for a prompt report. The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen's University Belfast, and the University of Edinburgh. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH). VMR acknowledges the Royal Astronomical Society and Emmanuel College, Cambridge, for financial support. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (AV, RDH). LM acknowledges the support by INAF/Frontiera through the 'Progetti Premiali' funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithsonian Astrophysical Observatory. CAW acknowledges support by STFC grant ST/P000312/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. This publication was made possible through the support of a grant from the John Templeton Foundation. The opinions expressed are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This material is based upon work supported by the National Aeronautics and Space Administration (NASA) under grants No. NNX15AC90G and NNX17AB59G issued through the Exoplanets Research Program. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France, NASA's Astrophysics Data System and the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundacion Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This paper includes data collected by the K2 mission. Funding for the K2 mission is provided by the NASA Science Mission directorate. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX13AC07G and by other grants and contracts. K2-263 was observed as part of the following Guest Programmes: GO5007 LC (PI: Winn), GO5029 LC (PI: Charbonneau), GO5033 LC (PI: Howard), GO5104 LC (PI: Dragomir), GO5106 LC (PI: Jackson), GO5060 LC (PI: Coughlin), GO16009 LC (PI: Charbonneau), GO16011 LC (PI: Fabrycky), GO16015 LC (PI: Boyajian), GO16020 LC (PI: Adams), GO16021 LC (PI: Howard), GO16101 LC (PI: Winn), GO16009 SC (PI: Charbonneau), GO16015 SC (PI: Boyajian), and GO16101 SC (PI: Winn). Funding Information: The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement number 313014 (ETAEARTH). VMR acknowledges the Royal Astronomical Society and Emmanuel College, Cambridge, for financial support. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (AV, RDH). LM acknowledges the support by INAF/Frontiera through the ‘Progetti Premiali’ funding scheme of the Italian Ministry of Education, University, and Research. ACC acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. DWL acknowledges partial support from the Kepler mission under NASA Cooperative Agreement NNX13AB58A with the Smithso-nian Astrophysical Observatory. CAW acknowledges support by STFC grant ST/P000312/1. Some of this work has been carried out within the framework of the NCCR PlanetS, supported by the Swiss National Science Foundation. This publication was made possible through the support of a grant from the John Temple-ton Foundation. The opinions expressed are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. Funding Information: The HARPS-N project has been funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard University Origins of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), and the Italian National Astrophysical Institute (INAF), the University of St Andrews, Queen’s University Belfast, and the University of Edinburgh. Publisher Copyright: © 2018 The Author(s).

PY - 2018/12/1

Y1 - 2018/12/1

N2 - This paper reports on the validation and mass measurement of K2-263 b, a sub-Neptune orbiting a quiet G9V star. Using K2 data from campaigns C5 and C16, we find this planet to have a period of 50.818947 ± 0.000094 d and a radius of 2.41 ± 0.12 R⊕. We followed this system with HARPS-N to obtain 67 precise radial velocities (RVs). A combined fit of the transit and radial velocity data reveals that K2-263 b has a mass of 14.8 ± 3.1M⊕. Its bulk density (5.7-1.4 +1.6 g cm-3) implies that this planet has a significant envelope of water or other volatiles around a rocky core. K2-263 b likely formed in a similar way as the cores of the four giant planets in our own Solar System, but for some reason, did not accrete much gas. The planetary mass was confirmed by an independent Gaussian process-based fit to both the RVs and the spectroscopic activity indicators. K2-263 b belongs to only a handful of confirmed K2 exoplanets with periods longer than 40 d. It is among the longest periods for a small planet with a precisely determined mass using RVs.

AB - This paper reports on the validation and mass measurement of K2-263 b, a sub-Neptune orbiting a quiet G9V star. Using K2 data from campaigns C5 and C16, we find this planet to have a period of 50.818947 ± 0.000094 d and a radius of 2.41 ± 0.12 R⊕. We followed this system with HARPS-N to obtain 67 precise radial velocities (RVs). A combined fit of the transit and radial velocity data reveals that K2-263 b has a mass of 14.8 ± 3.1M⊕. Its bulk density (5.7-1.4 +1.6 g cm-3) implies that this planet has a significant envelope of water or other volatiles around a rocky core. K2-263 b likely formed in a similar way as the cores of the four giant planets in our own Solar System, but for some reason, did not accrete much gas. The planetary mass was confirmed by an independent Gaussian process-based fit to both the RVs and the spectroscopic activity indicators. K2-263 b belongs to only a handful of confirmed K2 exoplanets with periods longer than 40 d. It is among the longest periods for a small planet with a precisely determined mass using RVs.

KW - Planets and satellites: individual: K2-263b

KW - Techniques: photometric

KW - Techniques: radial velocities

KW - Techniques: spectroscopic

UR - http://www.scopus.com/inward/record.url?scp=85060873232&partnerID=8YFLogxK

U2 - 10.1093/MNRAS/STY2360

DO - 10.1093/MNRAS/STY2360

M3 - Article

AN - SCOPUS:85060873232

SN - 0035-8711

VL - 481

SP - 1839

EP - 1847

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 2

ER -

K2-263 b: A 50 d period sub-Neptune with a mass measurement using HARPS-N

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

Access to Document

Fingerprint

Cite this