THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR

Vincent Van Eylen; Simon Albrecht; Davide Gandolfi; Fei Dai; Joshua N. Winn; Teriyuki Hirano; Norio Narita; Hans Bruntt; Jorge Prieto-Arranz; Víctor J.S. Béjar; Grzegorz Nowak; Mikkel N. Lund; Enric Palle; Ignasi Ribas; Roberto Sanchis-Ojeda; Liang Yu; Pamela Arriagada; R. Paul Butler; Jeffrey D. Crane; Rasmus Handberg; Hans Deeg; Jens Jessen-Hansen; John A. Johnson; David Nespral; Leslie Rogers; Tsuguru Ryu; Stephen Shectman; Tushar Shrotriya; Ditte Slumstrup; Yoichi Takeda; Johanna Teske; Ian Thompson; Andrew Vanderburg; Robert Wittenmyer

doi:10.3847/0004-6256/152/5/143

THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR

Vincent Van Eylen, Simon Albrecht, Davide Gandolfi, Fei Dai, Joshua N. Winn, Teriyuki Hirano, Norio Narita, Hans Bruntt, Jorge Prieto-Arranz, Víctor J.S. Béjar, Grzegorz Nowak, Mikkel N. Lund, Enric Palle, Ignasi Ribas, Roberto Sanchis-Ojeda, Liang Yu, Pamela Arriagada, R. Paul Butler, Jeffrey D. Crane, Rasmus HandbergHans Deeg, Jens Jessen-Hansen, John A. Johnson, David Nespral, Leslie Rogers, Tsuguru Ryu, Stephen Shectman, Tushar Shrotriya, Ditte Slumstrup, Yoichi Takeda, Johanna Teske, Ian Thompson, Andrew Vanderburg, Robert Wittenmyer

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33 Scopus citations

Abstract

We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 (EPIC206247743) is an evolved star with a spectroscopically derived stellar radius and mass of 3.88 0.42 0.48 R and 1.53+0.12 0.13 M, respectively, and a very close-in transiting planet, with a R = 3.4. Radial velocity (RV) follow-up using the HARPS, FIES, and PFS instruments leads to a planetary mass of 50.3 9.4 9.7 M. In combination with a radius measurement of 8.3 1.1 R, this results in a mean planetary density of 0.50+0.17 0.29 gcm^-3. We furthermore discover a long-term RV trend, which may be caused by a longperiod planet or stellar companion. Because K2-39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and mainsequence stars. Future monitoring of the transits of this system may enable the detection of period decay and constrain the tidal dissipation rates of subgiant stars.

Original language	English (US)
Article number	143
Journal	Astronomical Journal
Volume	152
Issue number	5
DOIs	https://doi.org/10.3847/0004-6256/152/5/143
State	Published - Nov 2016
Externally published	Yes

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

planetary systems
planets and satellites: detection
planets and satellites: dynamical evolution and stability
stars: fundamental parameters
stars: individual (K2-39)

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10.3847/0004-6256/152/5/143

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Van Eylen, V., Albrecht, S., Gandolfi, D., Dai, F., Winn, J. N., Hirano, T., Narita, N., Bruntt, H., Prieto-Arranz, J., Béjar, V. J. S., Nowak, G., Lund, M. N., Palle, E., Ribas, I., Sanchis-Ojeda, R., Yu, L., Arriagada, P., Butler, R. P., Crane, J. D., ... Wittenmyer, R. (2016). THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR. Astronomical Journal, 152(5), Article 143. https://doi.org/10.3847/0004-6256/152/5/143

@article{c0c9e623d0814d349d6c9e138b3a752f,

title = "THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR",

abstract = "We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 (EPIC206247743) is an evolved star with a spectroscopically derived stellar radius and mass of 3.88 0.42 0.48 R and 1.53+0.12 0.13 M, respectively, and a very close-in transiting planet, with a R = 3.4. Radial velocity (RV) follow-up using the HARPS, FIES, and PFS instruments leads to a planetary mass of 50.3 9.4 9.7 M. In combination with a radius measurement of 8.3 1.1 R, this results in a mean planetary density of 0.50+0.17 0.29 gcm-3. We furthermore discover a long-term RV trend, which may be caused by a longperiod planet or stellar companion. Because K2-39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and mainsequence stars. Future monitoring of the transits of this system may enable the detection of period decay and constrain the tidal dissipation rates of subgiant stars.",

keywords = "planetary systems, planets and satellites: detection, planets and satellites: dynamical evolution and stability, stars: fundamental parameters, stars: individual (K2-39)",

author = "{Van Eylen}, Vincent and Simon Albrecht and Davide Gandolfi and Fei Dai and Winn, {Joshua N.} and Teriyuki Hirano and Norio Narita and Hans Bruntt and Jorge Prieto-Arranz and B{\'e}jar, {V{\'i}ctor J.S.} and Grzegorz Nowak and Lund, {Mikkel N.} and Enric Palle and Ignasi Ribas and Roberto Sanchis-Ojeda and Liang Yu and Pamela Arriagada and Butler, {R. Paul} and Crane, {Jeffrey D.} and Rasmus Handberg and Hans Deeg and Jens Jessen-Hansen and Johnson, {John A.} and David Nespral and Leslie Rogers and Tsuguru Ryu and Stephen Shectman and Tushar Shrotriya and Ditte Slumstrup and Yoichi Takeda and Johanna Teske and Ian Thompson and Andrew Vanderburg and Robert Wittenmyer",

year = "2016",

month = nov,

doi = "10.3847/0004-6256/152/5/143",

language = "English (US)",

volume = "152",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "IOP Publishing Ltd.",

number = "5",

}

Van Eylen, V, Albrecht, S, Gandolfi, D, Dai, F, Winn, JN, Hirano, T, Narita, N, Bruntt, H, Prieto-Arranz, J, Béjar, VJS, Nowak, G, Lund, MN, Palle, E, Ribas, I, Sanchis-Ojeda, R, Yu, L, Arriagada, P, Butler, RP, Crane, JD, Handberg, R, Deeg, H, Jessen-Hansen, J, Johnson, JA, Nespral, D, Rogers, L, Ryu, T, Shectman, S, Shrotriya, T, Slumstrup, D, Takeda, Y, Teske, J, Thompson, I, Vanderburg, A & Wittenmyer, R 2016, 'THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR', Astronomical Journal, vol. 152, no. 5, 143. https://doi.org/10.3847/0004-6256/152/5/143

TY - JOUR

T1 - THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR

AU - Van Eylen, Vincent

AU - Albrecht, Simon

AU - Gandolfi, Davide

AU - Dai, Fei

AU - Winn, Joshua N.

AU - Hirano, Teriyuki

AU - Narita, Norio

AU - Bruntt, Hans

AU - Prieto-Arranz, Jorge

AU - Béjar, Víctor J.S.

AU - Nowak, Grzegorz

AU - Lund, Mikkel N.

AU - Palle, Enric

AU - Ribas, Ignasi

AU - Sanchis-Ojeda, Roberto

AU - Yu, Liang

AU - Arriagada, Pamela

AU - Butler, R. Paul

AU - Crane, Jeffrey D.

AU - Handberg, Rasmus

AU - Deeg, Hans

AU - Jessen-Hansen, Jens

AU - Johnson, John A.

AU - Nespral, David

AU - Rogers, Leslie

AU - Ryu, Tsuguru

AU - Shectman, Stephen

AU - Shrotriya, Tushar

AU - Slumstrup, Ditte

AU - Takeda, Yoichi

AU - Teske, Johanna

AU - Thompson, Ian

AU - Vanderburg, Andrew

AU - Wittenmyer, Robert

PY - 2016/11

Y1 - 2016/11

N2 - We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 (EPIC206247743) is an evolved star with a spectroscopically derived stellar radius and mass of 3.88 0.42 0.48 R and 1.53+0.12 0.13 M, respectively, and a very close-in transiting planet, with a R = 3.4. Radial velocity (RV) follow-up using the HARPS, FIES, and PFS instruments leads to a planetary mass of 50.3 9.4 9.7 M. In combination with a radius measurement of 8.3 1.1 R, this results in a mean planetary density of 0.50+0.17 0.29 gcm-3. We furthermore discover a long-term RV trend, which may be caused by a longperiod planet or stellar companion. Because K2-39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and mainsequence stars. Future monitoring of the transits of this system may enable the detection of period decay and constrain the tidal dissipation rates of subgiant stars.

AB - We report on the discovery and characterization of the transiting planet K2-39b (EPIC 206247743b). With an orbital period of 4.6 days, it is the shortest-period planet orbiting a subgiant star known to date. Such planets are rare, with only a handful of known cases. The reason for this is poorly understood but may reflect differences in planet occurrence around the relatively high-mass stars that have been surveyed, or may be the result of tidal destruction of such planets. K2-39 (EPIC206247743) is an evolved star with a spectroscopically derived stellar radius and mass of 3.88 0.42 0.48 R and 1.53+0.12 0.13 M, respectively, and a very close-in transiting planet, with a R = 3.4. Radial velocity (RV) follow-up using the HARPS, FIES, and PFS instruments leads to a planetary mass of 50.3 9.4 9.7 M. In combination with a radius measurement of 8.3 1.1 R, this results in a mean planetary density of 0.50+0.17 0.29 gcm-3. We furthermore discover a long-term RV trend, which may be caused by a longperiod planet or stellar companion. Because K2-39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and mainsequence stars. Future monitoring of the transits of this system may enable the detection of period decay and constrain the tidal dissipation rates of subgiant stars.

KW - planetary systems

KW - planets and satellites: detection

KW - planets and satellites: dynamical evolution and stability

KW - stars: fundamental parameters

KW - stars: individual (K2-39)

UR - http://www.scopus.com/inward/record.url?scp=84994520447&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84994520447&partnerID=8YFLogxK

U2 - 10.3847/0004-6256/152/5/143

DO - 10.3847/0004-6256/152/5/143

M3 - Article

AN - SCOPUS:84994520447

SN - 0004-6256

VL - 152

JO - Astronomical Journal

JF - Astronomical Journal

IS - 5

M1 - 143

ER -

THE K2-ESPRINT PROJECT. V. A SHORT-PERIOD GIANT PLANET ORBITING A SUBGIANT STAR

Abstract

All Science Journal Classification (ASJC) codes

Keywords

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