K2-110 b: a massive mini-Neptune exoplanet

H. P. Osborn; A. Santerne; S. C. C. Barros; N. C. Santos; X. Dumusque; L. Malavolta; D. J. Armstrong; S. Hojjatpanah; O. Demangeon; V. Adibekyan; J.-M. Almenara; D. Barrado; D. Bayliss; I. Boisse; F. Bouchy; D. J. A. Brown; A. C. Cameron; D. Charbonneau; M. Deleuil; E. Delgado Mena; R. F. Díaz; G. Hébrard; J. Kirk; G.W. King; K. W. F. Lam; D. Latham; J. Lillo-Box; T. M. Louden; C. Lovis; M. Marmier; J. McCormac; E. Molinari; F. Pepe; D. Pollacco; S. G. Sousa; S. Udry; S. R. Walker

doi:10.1051/0004-6361/201628932

K2-110 b: a massive mini-Neptune exoplanet

H. P. Osborn, A. Santerne, S. C. C. Barros, N. C. Santos, X. Dumusque, L. Malavolta, D. J. Armstrong, S. Hojjatpanah, O. Demangeon, V. Adibekyan, J.-M. Almenara, D. Barrado, D. Bayliss, I. Boisse, F. Bouchy, D. J. A. Brown, A. C. Cameron, D. Charbonneau, M. Deleuil, E. Delgado MenaR. F. Díaz, G. Hébrard, J. Kirk, G.W. King, K. W. F. Lam, D. Latham, J. Lillo-Box, T. M. Louden, C. Lovis, M. Marmier, J. McCormac, E. Molinari, F. Pepe, D. Pollacco, S. G. Sousa, S. Udry, S. R. Walker

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Abstract

We report the discovery of the exoplanet K2-110 b (previously EPIC212521166b) from K2 photometry orbiting in a 13.8637d period around an old, metal-poor K3 dwarf star. With a V-band magnitude of 11.9,K2-110 is particularly amenable to RV follow-up. A joint analysis of K2 photometry and high-precision RVs from 28 HARPS and HARPS-N spectra reveal it to have a radius of 2.6 ± 0.1R⊕ and amass of 16.7 ± 3.2M⊕, hence a density of 5.2± 1.2 g cm^-3, making it one of the most massive planets yet to be found with a sub-Neptune radius. When accounting for compression, the resulting Earth-like density is best fitted by a 0.2M⊕ hydrogen atmosphere over an 16.5M⊕ Earth-like interior, although the planet could also have significant water content. At 0.1 AU, even taking into account the old stellar age of 8 ± 3 Gyr, the planet is unlikely to have been significantly affected by EUV evaporation. However the planet likely disc-migrated to its current position making the lack of a thick H2 atmosphere puzzling. This analysis has made K2-110 b one of the best-characterised mini-Neptunes with density constrained to less than 30%.

Original language	English
Article number	A19
Number of pages	8
Journal	Astronomy & Astrophysics
Volume	604
Early online date	27 Jul 2017
DOIs	https://doi.org/10.1051/0004-6361/201628932
Publication status	Published - Aug 2017

Keywords

Planets and satellites
Detection

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10.1051/0004-6361/201628932

Osborn-2017-K2-110b-A&A-AAM
© 2017, ESO. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at www.aanda.org / https://doi.org/10.1051/0004-6361/201628932
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Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018
Jardine, M. M. (PI), Cameron, A. C. (CoI), Cyganowski, C. J. (CoI), Horne, K. D. (CoI) & Wood, K. (CoI)
Science & Technology Facilities Council
1/04/15 → 31/03/18
Project: Standard

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Osborn, H. P., Santerne, A., Barros, S. C. C., Santos, N. C., Dumusque, X., Malavolta, L., Armstrong, D. J., Hojjatpanah, S., Demangeon, O., Adibekyan, V., Almenara, J.-M., Barrado, D., Bayliss, D., Boisse, I., Bouchy, F., Brown, D. J. A., Cameron, A. C., Charbonneau, D., Deleuil, M., ... Walker, S. R. (2017). K2-110 b: a massive mini-Neptune exoplanet. Astronomy & Astrophysics, 604, Article A19. https://doi.org/10.1051/0004-6361/201628932

@article{9358d024863a41a297ceb0aeffe15d15,

title = "K2-110 b: a massive mini-Neptune exoplanet",

abstract = "We report the discovery of the exoplanet K2-110 b (previously EPIC212521166b) from K2 photometry orbiting in a 13.8637d period around an old, metal-poor K3 dwarf star. With a V-band magnitude of 11.9,K2-110 is particularly amenable to RV follow-up. A joint analysis of K2 photometry and high-precision RVs from 28 HARPS and HARPS-N spectra reveal it to have a radius of 2.6 ± 0.1R⊕ and amass of 16.7 ± 3.2M⊕, hence a density of 5.2± 1.2 g cm-3, making it one of the most massive planets yet to be found with a sub-Neptune radius. When accounting for compression, the resulting Earth-like density is best fitted by a 0.2M⊕ hydrogen atmosphere over an 16.5M⊕ Earth-like interior, although the planet could also have significant water content. At 0.1 AU, even taking into account the old stellar age of 8 ± 3 Gyr, the planet is unlikely to have been significantly affected by EUV evaporation. However the planet likely disc-migrated to its current position making the lack of a thick H2 atmosphere puzzling. This analysis has made K2-110 b one of the best-characterised mini-Neptunes with density constrained to less than 30%.",

keywords = "Planets and satellites, Detection",

author = "Osborn, {H. P.} and A. Santerne and Barros, {S. C. C.} and Santos, {N. C.} and X. Dumusque and L. Malavolta and Armstrong, {D. J.} and S. Hojjatpanah and O. Demangeon and V. Adibekyan and J.-M. Almenara and D. Barrado and D. Bayliss and I. Boisse and F. Bouchy and Brown, {D. J. A.} and Cameron, {A. C.} and D. Charbonneau and M. Deleuil and {Delgado Mena}, E. and D{\'i}az, {R. F.} and G. H{\'e}brard and J. Kirk and G.W. King and Lam, {K. W. F.} and D. Latham and J. Lillo-Box and Louden, {T. M.} and C. Lovis and M. Marmier and J. McCormac and E. Molinari and F. Pepe and D. Pollacco and Sousa, {S. G.} and S. Udry and Walker, {S. R.}",

year = "2017",

month = aug,

doi = "10.1051/0004-6361/201628932",

language = "English",

volume = "604",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

Osborn, HP, Santerne, A, Barros, SCC, Santos, NC, Dumusque, X, Malavolta, L, Armstrong, DJ, Hojjatpanah, S, Demangeon, O, Adibekyan, V, Almenara, J-M, Barrado, D, Bayliss, D, Boisse, I, Bouchy, F, Brown, DJA, Cameron, AC, Charbonneau, D, Deleuil, M, Delgado Mena, E, Díaz, RF, Hébrard, G, Kirk, J, King, GW, Lam, KWF, Latham, D, Lillo-Box, J, Louden, TM, Lovis, C, Marmier, M, McCormac, J, Molinari, E, Pepe, F, Pollacco, D, Sousa, SG, Udry, S & Walker, SR 2017, 'K2-110 b: a massive mini-Neptune exoplanet', Astronomy & Astrophysics, vol. 604, A19. https://doi.org/10.1051/0004-6361/201628932

TY - JOUR

T1 - K2-110 b: a massive mini-Neptune exoplanet

AU - Osborn, H. P.

AU - Santerne, A.

AU - Barros, S. C. C.

AU - Santos, N. C.

AU - Dumusque, X.

AU - Malavolta, L.

AU - Armstrong, D. J.

AU - Hojjatpanah, S.

AU - Demangeon, O.

AU - Adibekyan, V.

AU - Almenara, J.-M.

AU - Barrado, D.

AU - Bayliss, D.

AU - Boisse, I.

AU - Bouchy, F.

AU - Brown, D. J. A.

AU - Cameron, A. C.

AU - Charbonneau, D.

AU - Deleuil, M.

AU - Delgado Mena, E.

AU - Díaz, R. F.

AU - Hébrard, G.

AU - Kirk, J.

AU - King, G.W.

AU - Lam, K. W. F.

AU - Latham, D.

AU - Lillo-Box, J.

AU - Louden, T. M.

AU - Lovis, C.

AU - Marmier, M.

AU - McCormac, J.

AU - Molinari, E.

AU - Pepe, F.

AU - Pollacco, D.

AU - Sousa, S. G.

AU - Udry, S.

AU - Walker, S. R.

PY - 2017/8

Y1 - 2017/8

N2 - We report the discovery of the exoplanet K2-110 b (previously EPIC212521166b) from K2 photometry orbiting in a 13.8637d period around an old, metal-poor K3 dwarf star. With a V-band magnitude of 11.9,K2-110 is particularly amenable to RV follow-up. A joint analysis of K2 photometry and high-precision RVs from 28 HARPS and HARPS-N spectra reveal it to have a radius of 2.6 ± 0.1R⊕ and amass of 16.7 ± 3.2M⊕, hence a density of 5.2± 1.2 g cm-3, making it one of the most massive planets yet to be found with a sub-Neptune radius. When accounting for compression, the resulting Earth-like density is best fitted by a 0.2M⊕ hydrogen atmosphere over an 16.5M⊕ Earth-like interior, although the planet could also have significant water content. At 0.1 AU, even taking into account the old stellar age of 8 ± 3 Gyr, the planet is unlikely to have been significantly affected by EUV evaporation. However the planet likely disc-migrated to its current position making the lack of a thick H2 atmosphere puzzling. This analysis has made K2-110 b one of the best-characterised mini-Neptunes with density constrained to less than 30%.

AB - We report the discovery of the exoplanet K2-110 b (previously EPIC212521166b) from K2 photometry orbiting in a 13.8637d period around an old, metal-poor K3 dwarf star. With a V-band magnitude of 11.9,K2-110 is particularly amenable to RV follow-up. A joint analysis of K2 photometry and high-precision RVs from 28 HARPS and HARPS-N spectra reveal it to have a radius of 2.6 ± 0.1R⊕ and amass of 16.7 ± 3.2M⊕, hence a density of 5.2± 1.2 g cm-3, making it one of the most massive planets yet to be found with a sub-Neptune radius. When accounting for compression, the resulting Earth-like density is best fitted by a 0.2M⊕ hydrogen atmosphere over an 16.5M⊕ Earth-like interior, although the planet could also have significant water content. At 0.1 AU, even taking into account the old stellar age of 8 ± 3 Gyr, the planet is unlikely to have been significantly affected by EUV evaporation. However the planet likely disc-migrated to its current position making the lack of a thick H2 atmosphere puzzling. This analysis has made K2-110 b one of the best-characterised mini-Neptunes with density constrained to less than 30%.

KW - Planets and satellites

KW - Detection

U2 - 10.1051/0004-6361/201628932

DO - 10.1051/0004-6361/201628932

M3 - Article

SN - 0004-6361

VL - 604

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A19

ER -

K2-110 b: a massive mini-Neptune exoplanet

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Keywords

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Astronomy at St Andrews 2015-2018: Astronomy at St Andrews 2015-2018

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