So close, so different: characterization of the K2-36 planetary system with HARPS-N

M. Damasso; L. Zeng; L. Malavolta; A. Mayo; A. Sozzetti; A. Mortier; L. A. Buchhave; A. Vanderburg; M. Lopez-Morales; A. S. Bonomo; A. C. Cameron; A. Coffinet; P. Figueira; D. W. Latham; M. Mayor; E. Molinari; F. Pepe; D. F. Phillips; E. Poretti; K. Rice; S. Udry; C. A. Watson

doi:10.1051/0004-6361/201834671

So close, so different: characterization of the K2-36 planetary system with HARPS-N

M. Damasso, L. Zeng, L. Malavolta, A. Mayo, A. Sozzetti, A. Mortier, L. A. Buchhave, A. Vanderburg, M. Lopez-Morales, A. S. Bonomo, A. C. Cameron, A. Coffinet, P. Figueira, D. W. Latham, M. Mayor, E. Molinari, F. Pepe, D. F. Phillips, E. Poretti, K. RiceS. Udry, C. A. Watson

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

Abstract

Context. K2-36 is a K dwarf orbited by two small (R_b = 1.43 ± 0.08 R⊕ and R_c = 3.2 ± 0.3 R⊕), close-in (a_b = 0.022 AU and a_c = 0.054 AU) transiting planets discovered by the Kepler/K2 space observatory. They are representatives of two distinct families of small planets (R_p < 4 R⊕) recently emerged from the analysis of Kepler data, with likely a different structure, composition and evolutionary pathways.

Aims. We revise the fundamental stellar parameters and the sizes of the planets, and provide the first measurement of their massesand bulk densities, which we use to infer their structure and composition.

Methods. We observed K2-36 with the HARPS-N spectrograph over∼3.5 years, collecting 81 useful radial velocity measurements. The star is active, with evidence for increasing levels of magnetic activity during the observing time span. The radial velocity scatter is ∼17 m s⁻¹ due to the stellar activity contribution, which is much larger than the semi-amplitudes of the planetary signals. We tested different methods for mitigating the stellar activity contribution to the radial velocity time variations and measuring the planet masses with good precision.

Results. We found that K2-36 is likely a∼1 Gyr old system, and by treating the stellar activity through a Gaussian process regression, we measured the planet masses mb = 3.9 ± 1.1 M⊕ and mc = 7.8 ± 2.3 M⊕. The derived planet bulk densities ρ_b = 7.2^+2.5_−2.1 g cm⁻³ and ρ_c = 1.3^+0.7_-0.5 g cm⁻³ point out that K2-36 b has a rocky, Earth-like composition, and K2-36 c is a low-density sub-Neptune.
Conclusions. Composed of two planets with similar orbital separations but different densities, K2-36 represents an optimal laboratory for testing the role of the atmospheric escape in driving the evolution of close-in, low-mass planets after ∼1 Gyr from their formation. Due to their similarities, we performed a preliminary comparative analysis between the systems K2-36 and Kepler-36, which we deem worthy of a more detailed investigation.

Original language	English
Article number	A38
Number of pages	19
Journal	Astronomy & Astrophysics
Volume	624
DOIs	https://doi.org/10.1051/0004-6361/201834671
Publication status	Published - 8 Apr 2019

Keywords

Stars- individual: K2-36 (TYC 266-622-1, EPIC 201713348)
Planets and satellites: detection
Planets and satellites: composition
Techniques: radial velocities

Access to Document

10.1051/0004-6361/201834671

1902.01881v1
Copyright 2019, 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 as such may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1051/0004-6361/201834671
Accepted author manuscript, 3.1 MB

Astronomy at St Andrews 2018-2021: Astronomy at St Andrews 2018-2021
Jardine, M. M. (PI), Bonnell, I. A. (CoI), Cameron, A. C. (CoI), Cyganowski, C. J. (CoI), Dominik, M. (CoI), Helling, C. (CoI), Horne, K. D. (CoI), Scholz, A. (CoI), Tojeiro, R. (CoI), Weijmans, A.-M. (CoI), Wild, V. (CoI), Woitke, P. (CoI), Wood, K. (CoI) & Zhao, H. (CoI)
1/04/18 → 31/03/22
Project: Standard
EU FP7 Space ETAEARTH: ETAEARTH
Cameron, A. C. (PI)
European Commission
1/01/13 → 31/12/17
Project: Standard

So close, so different: characterization of the K2-36 planetary system with HARPS-N (dataset)
Damasso, M. (Creator), Zeng, L. (Creator), Malavolta, L. (Creator), Mayo, A. (Creator), Sozzetti, A. (Creator), Mortier, A. (Creator), Buchhave, L. A. (Creator), Vanderburg, A. (Creator), Lopez-Morales, M. (Creator), Bonomo, A. S. (Creator), Cameron, A. C. (Creator), Coffinet, A. (Creator), Figueira, P. (Creator), Latham, D. W. (Creator), Mayor, M. (Creator), Molinari, E. (Creator), Pepe, F. (Creator), Phillips, D. F. (Creator), Poretti, E. (Creator), Rice, K. (Creator), Udry, S. (Creator) & Watson, C. A. (Creator), Université de Strasbourg/CNRS, 8 Apr 2019
http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A38
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Damasso, M., Zeng, L., Malavolta, L., Mayo, A., Sozzetti, A., Mortier, A., Buchhave, L. A., Vanderburg, A., Lopez-Morales, M., Bonomo, A. S., Cameron, A. C., Coffinet, A., Figueira, P., Latham, D. W., Mayor, M., Molinari, E., Pepe, F., Phillips, D. F., Poretti, E., ... Watson, C. A. (2019). So close, so different: characterization of the K2-36 planetary system with HARPS-N. Astronomy & Astrophysics, 624, Article A38. https://doi.org/10.1051/0004-6361/201834671

@article{5ff57b25ca404cc0b66f8cf0eff74deb,

title = "So close, so different: characterization of the K2-36 planetary system with HARPS-N",

abstract = "Context. K2-36 is a K dwarf orbited by two small (Rb = 1.43 ± 0.08 R⊕ and Rc = 3.2 ± 0.3 R⊕), close-in (ab = 0.022 AU and ac = 0.054 AU) transiting planets discovered by the Kepler/K2 space observatory. They are representatives of two distinct families of small planets (Rp < 4 R⊕) recently emerged from the analysis of Kepler data, with likely a different structure, composition and evolutionary pathways.Aims. We revise the fundamental stellar parameters and the sizes of the planets, and provide the first measurement of their massesand bulk densities, which we use to infer their structure and composition.Methods. We observed K2-36 with the HARPS-N spectrograph over∼3.5 years, collecting 81 useful radial velocity measurements. The star is active, with evidence for increasing levels of magnetic activity during the observing time span. The radial velocity scatter is ∼17 m s−1 due to the stellar activity contribution, which is much larger than the semi-amplitudes of the planetary signals. We tested different methods for mitigating the stellar activity contribution to the radial velocity time variations and measuring the planet masses with good precision.Results. We found that K2-36 is likely a∼1 Gyr old system, and by treating the stellar activity through a Gaussian process regression, we measured the planet masses mb = 3.9 ± 1.1 M⊕ and mc = 7.8 ± 2.3 M⊕. The derived planet bulk densities ρb = 7.2+2.5−2.1 g cm−3 and ρc = 1.3+0.7-0.5 g cm−3 point out that K2-36 b has a rocky, Earth-like composition, and K2-36 c is a low-density sub-Neptune.Conclusions. Composed of two planets with similar orbital separations but different densities, K2-36 represents an optimal laboratory for testing the role of the atmospheric escape in driving the evolution of close-in, low-mass planets after ∼1 Gyr from their formation. Due to their similarities, we performed a preliminary comparative analysis between the systems K2-36 and Kepler-36, which we deem worthy of a more detailed investigation.",

keywords = "Stars- individual: K2-36 (TYC 266-622-1, EPIC 201713348), Planets and satellites: detection, Planets and satellites: composition, Techniques: radial velocities",

author = "M. Damasso and L. Zeng and L. Malavolta and A. Mayo and A. Sozzetti and A. Mortier and Buchhave, {L. A.} and A. Vanderburg and M. Lopez-Morales and Bonomo, {A. S.} and Cameron, {A. C.} and A. Coffinet and P. Figueira and Latham, {D. W.} and M. Mayor and E. Molinari and F. Pepe and Phillips, {D. F.} and E. Poretti and K. Rice and S. Udry and Watson, {C. A.}",

note = "A.C.C. acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. C.A.W. acknowledges support from the STFC grant ST/P000312/1. 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. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007- 2013) under grant agreement number 313014 (ETAEARTH).",

year = "2019",

month = apr,

day = "8",

doi = "10.1051/0004-6361/201834671",

language = "English",

volume = "624",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

Damasso, M, Zeng, L, Malavolta, L, Mayo, A, Sozzetti, A, Mortier, A, Buchhave, LA, Vanderburg, A, Lopez-Morales, M, Bonomo, AS, Cameron, AC, Coffinet, A, Figueira, P, Latham, DW, Mayor, M, Molinari, E, Pepe, F, Phillips, DF, Poretti, E, Rice, K, Udry, S & Watson, CA 2019, 'So close, so different: characterization of the K2-36 planetary system with HARPS-N', Astronomy & Astrophysics, vol. 624, A38. https://doi.org/10.1051/0004-6361/201834671

TY - JOUR

T1 - So close, so different

T2 - characterization of the K2-36 planetary system with HARPS-N

AU - Damasso, M.

AU - Zeng, L.

AU - Malavolta, L.

AU - Mayo, A.

AU - Sozzetti, A.

AU - Mortier, A.

AU - Buchhave, L. A.

AU - Vanderburg, A.

AU - Lopez-Morales, M.

AU - Bonomo, A. S.

AU - Cameron, A. C.

AU - Coffinet, A.

AU - Figueira, P.

AU - Latham, D. W.

AU - Mayor, M.

AU - Molinari, E.

AU - Pepe, F.

AU - Phillips, D. F.

AU - Poretti, E.

AU - Rice, K.

AU - Udry, S.

AU - Watson, C. A.

N1 - A.C.C. acknowledges support from the Science & Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. C.A.W. acknowledges support from the STFC grant ST/P000312/1. 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).

PY - 2019/4/8

Y1 - 2019/4/8

N2 - Context. K2-36 is a K dwarf orbited by two small (Rb = 1.43 ± 0.08 R⊕ and Rc = 3.2 ± 0.3 R⊕), close-in (ab = 0.022 AU and ac = 0.054 AU) transiting planets discovered by the Kepler/K2 space observatory. They are representatives of two distinct families of small planets (Rp < 4 R⊕) recently emerged from the analysis of Kepler data, with likely a different structure, composition and evolutionary pathways.Aims. We revise the fundamental stellar parameters and the sizes of the planets, and provide the first measurement of their massesand bulk densities, which we use to infer their structure and composition.Methods. We observed K2-36 with the HARPS-N spectrograph over∼3.5 years, collecting 81 useful radial velocity measurements. The star is active, with evidence for increasing levels of magnetic activity during the observing time span. The radial velocity scatter is ∼17 m s−1 due to the stellar activity contribution, which is much larger than the semi-amplitudes of the planetary signals. We tested different methods for mitigating the stellar activity contribution to the radial velocity time variations and measuring the planet masses with good precision.Results. We found that K2-36 is likely a∼1 Gyr old system, and by treating the stellar activity through a Gaussian process regression, we measured the planet masses mb = 3.9 ± 1.1 M⊕ and mc = 7.8 ± 2.3 M⊕. The derived planet bulk densities ρb = 7.2+2.5−2.1 g cm−3 and ρc = 1.3+0.7-0.5 g cm−3 point out that K2-36 b has a rocky, Earth-like composition, and K2-36 c is a low-density sub-Neptune.Conclusions. Composed of two planets with similar orbital separations but different densities, K2-36 represents an optimal laboratory for testing the role of the atmospheric escape in driving the evolution of close-in, low-mass planets after ∼1 Gyr from their formation. Due to their similarities, we performed a preliminary comparative analysis between the systems K2-36 and Kepler-36, which we deem worthy of a more detailed investigation.

AB - Context. K2-36 is a K dwarf orbited by two small (Rb = 1.43 ± 0.08 R⊕ and Rc = 3.2 ± 0.3 R⊕), close-in (ab = 0.022 AU and ac = 0.054 AU) transiting planets discovered by the Kepler/K2 space observatory. They are representatives of two distinct families of small planets (Rp < 4 R⊕) recently emerged from the analysis of Kepler data, with likely a different structure, composition and evolutionary pathways.Aims. We revise the fundamental stellar parameters and the sizes of the planets, and provide the first measurement of their massesand bulk densities, which we use to infer their structure and composition.Methods. We observed K2-36 with the HARPS-N spectrograph over∼3.5 years, collecting 81 useful radial velocity measurements. The star is active, with evidence for increasing levels of magnetic activity during the observing time span. The radial velocity scatter is ∼17 m s−1 due to the stellar activity contribution, which is much larger than the semi-amplitudes of the planetary signals. We tested different methods for mitigating the stellar activity contribution to the radial velocity time variations and measuring the planet masses with good precision.Results. We found that K2-36 is likely a∼1 Gyr old system, and by treating the stellar activity through a Gaussian process regression, we measured the planet masses mb = 3.9 ± 1.1 M⊕ and mc = 7.8 ± 2.3 M⊕. The derived planet bulk densities ρb = 7.2+2.5−2.1 g cm−3 and ρc = 1.3+0.7-0.5 g cm−3 point out that K2-36 b has a rocky, Earth-like composition, and K2-36 c is a low-density sub-Neptune.Conclusions. Composed of two planets with similar orbital separations but different densities, K2-36 represents an optimal laboratory for testing the role of the atmospheric escape in driving the evolution of close-in, low-mass planets after ∼1 Gyr from their formation. Due to their similarities, we performed a preliminary comparative analysis between the systems K2-36 and Kepler-36, which we deem worthy of a more detailed investigation.

KW - Stars- individual: K2-36 (TYC 266-622-1, EPIC 201713348)

KW - Planets and satellites: detection

KW - Planets and satellites: composition

KW - Techniques: radial velocities

U2 - 10.1051/0004-6361/201834671

DO - 10.1051/0004-6361/201834671

M3 - Article

SN - 0004-6361

VL - 624

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A38

ER -

So close, so different: characterization of the K2-36 planetary system with HARPS-N

Abstract

Keywords

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Projects

Astronomy at St Andrews 2018-2021: Astronomy at St Andrews 2018-2021

EU FP7 Space ETAEARTH: ETAEARTH

Datasets

So close, so different: characterization of the K2-36 planetary system with HARPS-N (dataset)

Cite this