Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS

M. Damasso; A. S. Bonomo; N. Astudillo-Defru; X. Bonfils; L. Malavolta; A. Sozzetti; E. Lopez; L. Zeng; R. D. Haywood; A. Mortier; A. Vanderburg; J. Maldonado; A. F. Lanza; L. Affer; J.-M. Almenara; S. Benatti; K. Biazzo; A. Bignamini; F. Borsa; F. Bouchy; L. A. Buchhave; I. Carleo; D. Charbonneau; R. Claudi; R. Cosentino; E. Covino; X. Delfosse; S. Desidera; L. Di Fabrizio; C. Dressing; R. Fares; P. Figueira; A. F. M. Fiorenzano; T. Forveille; P. Giacobbe; E. González-Álvarez; R. Gratton; A. Harutyunyan; J. Asher Johnson; D. W. Latham; G. Leto; M. Lopez-Morales; C. Lovis; A. Maggio; S. Masiero; M. Mayor; G. Micela; E. Molinari; F. Motalebi; F. Murgas; V. Nascimbeni; I. Pagano; F. Pepe; G. Piotto; E. Poretti; M. Rainer; K. Rice; N. C. Santos; D. Sasselov; G. Scandariato; D. Ségransan; R. Smareglia; S. Udry; C. Watson; A. Wünsche

doi:10.1051/0004-6361/201732459

Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS

M. Damasso, A. S. Bonomo, N. Astudillo-Defru, X. Bonfils, L. Malavolta, A. Sozzetti, E. Lopez, L. Zeng, R. D. Haywood, A. Mortier, A. Vanderburg, J. Maldonado, A. F. Lanza, L. Affer, J.-M. Almenara, S. Benatti, K. Biazzo, A. Bignamini, F. Borsa, F. BouchyL. A. Buchhave, I. Carleo, D. Charbonneau, R. Claudi, R. Cosentino, E. Covino, X. Delfosse, S. Desidera, L. Di Fabrizio, C. Dressing, R. Fares, P. Figueira, A. F. M. Fiorenzano, T. Forveille, P. Giacobbe, E. González-Álvarez, R. Gratton, A. Harutyunyan, J. Asher Johnson, D. W. Latham, G. Leto, M. Lopez-Morales, C. Lovis, A. Maggio, S. Masiero, M. Mayor, G. Micela, E. Molinari, F. Motalebi, F. Murgas, V. Nascimbeni, I. Pagano, F. Pepe, G. Piotto, E. Poretti, M. Rainer, K. Rice, N. C. Santos, D. Sasselov, G. Scandariato, D. Ségransan, R. Smareglia, S. Udry, C. Watson, A. Wünsche

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

Abstract

Context. M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Aims: Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. Methods: We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Results: Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb = 6.6 ± 1.1 M⊕) and planet c (Mc = 3.1-1.2+1.3 M⊕). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md = 2.7-0.8+1.2 M⊕ M⊕. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (

Original language	English
Journal	Astronomy & Astrophysics
Volume	615
DOIs	https://doi.org/10.1051/0004-6361/201732459
Publication status	Published - 1 Jul 2018

Keywords / Materials (for Non-textual outputs)

stars: individual: K2-3
planets and satellites: detection
planets and satellites: composition
techniques: radial velocities
stars: individual: EPIC 201367065
stars: individual: 2MASS 11292037-0127173

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Damasso, M., Bonomo, A. S., Astudillo-Defru, N., Bonfils, X., Malavolta, L., Sozzetti, A., Lopez, E., Zeng, L., Haywood, R. D., Mortier, A., Vanderburg, A., Maldonado, J., Lanza, A. F., Affer, L., Almenara, J.-M., Benatti, S., Biazzo, K., Bignamini, A., Borsa, F., ... Wünsche, A. (2018). Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS. Astronomy & Astrophysics, 615. https://doi.org/10.1051/0004-6361/201732459

@article{331369f88cfb4a17bb77bbbfe3571359,

title = "Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS",

abstract = "Context. M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Aims: Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. Methods: We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Results: Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb = 6.6 ± 1.1 M⊕) and planet c (Mc = 3.1-1.2+1.3 M⊕). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md = 2.7-0.8+1.2 M⊕ M⊕. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (",

keywords = "stars: individual: K2-3, planets and satellites: detection, planets and satellites: composition, techniques: radial velocities, stars: individual: EPIC 201367065, stars: individual: 2MASS 11292037-0127173",

author = "M. Damasso and Bonomo, \{A. S.\} and N. Astudillo-Defru and X. Bonfils and L. Malavolta and A. Sozzetti and E. Lopez and L. Zeng and Haywood, \{R. D.\} and A. Mortier and A. Vanderburg and J. Maldonado and Lanza, \{A. F.\} and L. Affer and J.-M. Almenara and S. Benatti and K. Biazzo and A. Bignamini and F. Borsa and F. Bouchy and Buchhave, \{L. A.\} and I. Carleo and D. Charbonneau and R. Claudi and R. Cosentino and E. Covino and X. Delfosse and S. Desidera and \{Di Fabrizio\}, L. and C. Dressing and R. Fares and P. Figueira and Fiorenzano, \{A. F. M.\} and T. Forveille and P. Giacobbe and E. Gonz{\'a}lez-{\'A}lvarez and R. Gratton and A. Harutyunyan and Johnson, \{J. Asher\} and Latham, \{D. W.\} and G. Leto and M. Lopez-Morales and C. Lovis and A. Maggio and S. Masiero and M. Mayor and G. Micela and E. Molinari and F. Motalebi and F. Murgas and V. Nascimbeni and I. Pagano and F. Pepe and G. Piotto and E. Poretti and M. Rainer and K. Rice and Santos, \{N. C.\} and D. Sasselov and G. Scandariato and D. S{\'e}gransan and R. Smareglia and S. Udry and C. Watson and A. W{\"u}nsche",

year = "2018",

month = jul,

day = "1",

doi = "10.1051/0004-6361/201732459",

language = "English",

volume = "615",

journal = "Astronomy \& Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

Damasso, M, Bonomo, AS, Astudillo-Defru, N, Bonfils, X, Malavolta, L, Sozzetti, A, Lopez, E, Zeng, L, Haywood, RD, Mortier, A, Vanderburg, A, Maldonado, J, Lanza, AF, Affer, L, Almenara, J-M, Benatti, S, Biazzo, K, Bignamini, A, Borsa, F, Bouchy, F, Buchhave, LA, Carleo, I, Charbonneau, D, Claudi, R, Cosentino, R, Covino, E, Delfosse, X, Desidera, S, Di Fabrizio, L, Dressing, C, Fares, R, Figueira, P, Fiorenzano, AFM, Forveille, T, Giacobbe, P, González-Álvarez, E, Gratton, R, Harutyunyan, A, Johnson, JA, Latham, DW, Leto, G, Lopez-Morales, M, Lovis, C, Maggio, A, Masiero, S, Mayor, M, Micela, G, Molinari, E, Motalebi, F, Murgas, F, Nascimbeni, V, Pagano, I, Pepe, F, Piotto, G, Poretti, E, Rainer, M, Rice, K, Santos, NC, Sasselov, D, Scandariato, G, Ségransan, D, Smareglia, R, Udry, S, Watson, C & Wünsche, A 2018, 'Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS', Astronomy & Astrophysics, vol. 615. https://doi.org/10.1051/0004-6361/201732459

TY - JOUR

T1 - Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS

AU - Damasso, M.

AU - Bonomo, A. S.

AU - Astudillo-Defru, N.

AU - Bonfils, X.

AU - Malavolta, L.

AU - Sozzetti, A.

AU - Lopez, E.

AU - Zeng, L.

AU - Haywood, R. D.

AU - Mortier, A.

AU - Vanderburg, A.

AU - Maldonado, J.

AU - Lanza, A. F.

AU - Affer, L.

AU - Almenara, J.-M.

AU - Benatti, S.

AU - Biazzo, K.

AU - Bignamini, A.

AU - Borsa, F.

AU - Bouchy, F.

AU - Buchhave, L. A.

AU - Carleo, I.

AU - Charbonneau, D.

AU - Claudi, R.

AU - Cosentino, R.

AU - Covino, E.

AU - Delfosse, X.

AU - Desidera, S.

AU - Di Fabrizio, L.

AU - Dressing, C.

AU - Fares, R.

AU - Figueira, P.

AU - Fiorenzano, A. F. M.

AU - Forveille, T.

AU - Giacobbe, P.

AU - González-Álvarez, E.

AU - Gratton, R.

AU - Harutyunyan, A.

AU - Johnson, J. Asher

AU - Latham, D. W.

AU - Leto, G.

AU - Lopez-Morales, M.

AU - Lovis, C.

AU - Maggio, A.

AU - Masiero, S.

AU - Mayor, M.

AU - Micela, G.

AU - Molinari, E.

AU - Motalebi, F.

AU - Murgas, F.

AU - Nascimbeni, V.

AU - Pagano, I.

AU - Pepe, F.

AU - Piotto, G.

AU - Poretti, E.

AU - Rainer, M.

AU - Rice, K.

AU - Santos, N. C.

AU - Sasselov, D.

AU - Scandariato, G.

AU - Ségransan, D.

AU - Smareglia, R.

AU - Udry, S.

AU - Watson, C.

AU - Wünsche, A.

PY - 2018/7/1

Y1 - 2018/7/1

N2 - Context. M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Aims: Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. Methods: We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Results: Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb = 6.6 ± 1.1 M⊕) and planet c (Mc = 3.1-1.2+1.3 M⊕). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md = 2.7-0.8+1.2 M⊕ M⊕. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (

AB - Context. M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to the inner edge of the stellar (optimistic) habitable zone. The K2-3 system is well suited for follow-up characterization studies aimed at determining accurate masses and bulk densities of the three planets. Aims: Using a total of 329 radial velocity measurements collected over 2.5 years with the HARPS-N and HARPS spectrographs and a proper treatment of the stellar activity signal, we aim to improve measurements of the masses and bulk densities of the K2-3 planets. We use our results to investigate the physical structure of the planets. Methods: We analysed radial velocity time series extracted with two independent pipelines using Gaussian process regression. We adopted a quasi-periodic kernel to model the stellar magnetic activity jointly with the planetary signals. We used Monte Carlo simulations to investigate the robustness of our mass measurements of K2-3 c and K2-3 d, and to explore how additional high-cadence radial velocity observations might improve these values. Results: Even though the stellar activity component is the strongest signal present in the radial velocity time series, we are able to derive masses for both planet b (Mb = 6.6 ± 1.1 M⊕) and planet c (Mc = 3.1-1.2+1.3 M⊕). The Doppler signal from K2-3 d remains undetected, likely because of its low amplitude compared to the radial velocity signal induced by the stellar activity. The closeness of the orbital period of K2-3 d to the stellar rotation period could also make the detection of the planetary signal complicated. Based on our ability to recover injected signals in simulated data, we tentatively estimate the mass of K2-3 d to be Md = 2.7-0.8+1.2 M⊕ M⊕. These mass measurements imply that the bulk densities and therefore the interior structures of the three planets may be similar. In particular, the planets may either have small H/He envelopes (

KW - stars: individual: K2-3

KW - planets and satellites: detection

KW - planets and satellites: composition

KW - techniques: radial velocities

KW - stars: individual: EPIC 201367065

KW - stars: individual: 2MASS 11292037-0127173

U2 - 10.1051/0004-6361/201732459

DO - 10.1051/0004-6361/201732459

M3 - Article

SN - 0004-6361

VL - 615

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

ER -

Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS

Abstract

Keywords / Materials (for Non-textual outputs)

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