A large sub-Neptune transiting the thick-disk M4 v TOI-2406

R. D. Wells; B. V. Rackham; N. Schanche; R. Petrucci; Y. Gómez Maqueo Chew; B. O. Demory; A. J. Burgasser; R. Burn; F. J. Pozuelos; M. N. Günther; L. Sabin; U. Schroffenegger; M. A. Gómez-Muñoz; K. G. Stassun; V. Van Grootel; S. B. Howell; D. Sebastian; A. H.M.J. Triaud; D. Apai; I. Plauchu-Frayn; C. A. Guerrero; P. F. Guillén; A. Landa; G. Melgoza; F. Montalvo; H. Serrano; H. Riesgo; K. Barkaoui; A. Bixel; A. Burdanov; W. P. Chen; P. Chinchilla; K. A. Collins; T. Daylan; J. De Wit; L. Delrez; M. Dévora-Pajares; J. Dietrich; G. Dransfield; E. Ducrot; M. Fausnaugh; E. Furlan; P. Gabor; T. Gan; L. Garcia; M. Ghachoui; S. Giacalone; A. B. Gibbs; M. Gillon; C. Gnilka; R. Gore; N. Guerrero; T. Henning; K. Hesse; E. Jehin; J. M. Jenkins; D. W. Latham; K. Lester; J. McCormac; C. A. Murray; P. Niraula; P. P. Pedersen; D. Queloz; G. Ricker; D. R. Rodriguez; A. Schroeder; R. P. Schwarz; N. Scott; S. Seager; C. A. Theissen; S. Thompson; M. Timmermans; J. D. Twicken; J. N. Winn

doi:10.1051/0004-6361/202141277

A large sub-Neptune transiting the thick-disk M4 v TOI-2406

R. D. Wells, B. V. Rackham, N. Schanche, R. Petrucci, Y. Gómez Maqueo Chew, B. O. Demory, A. J. Burgasser, R. Burn, F. J. Pozuelos, M. N. Günther, L. Sabin, U. Schroffenegger, M. A. Gómez-Muñoz, K. G. Stassun, V. Van Grootel, S. B. Howell, D. Sebastian, A. H.M.J. Triaud, D. Apai, I. Plauchu-FraynC. A. Guerrero, P. F. Guillén, A. Landa, G. Melgoza, F. Montalvo, H. Serrano, H. Riesgo, K. Barkaoui, A. Bixel, A. Burdanov, W. P. Chen, P. Chinchilla, K. A. Collins, T. Daylan, J. De Wit, L. Delrez, M. Dévora-Pajares, J. Dietrich, G. Dransfield, E. Ducrot, M. Fausnaugh, E. Furlan, P. Gabor, T. Gan, L. Garcia, M. Ghachoui, S. Giacalone, A. B. Gibbs, M. Gillon, C. Gnilka, R. Gore, N. Guerrero, T. Henning, K. Hesse, E. Jehin, J. M. Jenkins, D. W. Latham, K. Lester, J. McCormac, C. A. Murray, P. Niraula, P. P. Pedersen, D. Queloz, G. Ricker, D. R. Rodriguez, A. Schroeder, R. P. Schwarz, N. Scott, S. Seager, C. A. Theissen, S. Thompson, M. Timmermans, J. D. Twicken, J. N. Winn

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Abstract

Context. Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these planets are highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST. Aims. Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. The star's low metallicity and the relatively large size and short period of the planet make TOI-2406 b an unusual outcome of planet formation, and its characterisation provides an important observational constraint for formation models. Methods. We first infer properties of the host star by analysing the star's near-infrared spectrum, spectral energy distribution, and Gaia parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data. Results. We determine the host to be a metal-poor M4 V star, located at a distance of 56 pc, with properties Teff = 3100 ± 75 K, M∗ = 0.162 ± 0.008Mo˙, R∗ = 0.202 ± 0.011Ro˙, and [Fe∕ H] = -0.38 ± 0.07, and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with Rp = 2.94 ± 0.17R⊕ and P= 3.077 d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3σ, prompting questions about the dynamical history of the system. Conclusions. This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy. Although the planet's mass remains to be constrained, we estimate the S/N using amass-radius relationship, ranking the system fifth in the population of large sub-Neptunes, with TOI-2406 b having a much lower equilibrium temperature than other spectroscopically accessible members of this population.

Original language	English (US)
Article number	A97
Journal	Astronomy and astrophysics
Volume	653
DOIs	https://doi.org/10.1051/0004-6361/202141277
State	Published - Sep 1 2021

Keywords

Planets and satellites: detection
Stars: individual: TOI-2406
Techniques: photometric

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1051/0004-6361/202141277

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Wells, R. D., Rackham, B. V., Schanche, N., Petrucci, R., Gómez Maqueo Chew, Y., Demory, B. O., Burgasser, A. J., Burn, R., Pozuelos, F. J., Günther, M. N., Sabin, L., Schroffenegger, U., Gómez-Muñoz, M. A., Stassun, K. G., Van Grootel, V., Howell, S. B., Sebastian, D., Triaud, A. H. M. J., Apai, D., ... Winn, J. N. (2021). A large sub-Neptune transiting the thick-disk M4 v TOI-2406. Astronomy and astrophysics, 653, Article A97. https://doi.org/10.1051/0004-6361/202141277

Wells, RD, Rackham, BV, Schanche, N, Petrucci, R, Gómez Maqueo Chew, Y, Demory, BO, Burgasser, AJ, Burn, R, Pozuelos, FJ, Günther, MN, Sabin, L, Schroffenegger, U, Gómez-Muñoz, MA, Stassun, KG, Van Grootel, V, Howell, SB, Sebastian, D, Triaud, AHMJ, Apai, D, Plauchu-Frayn, I, Guerrero, CA, Guillén, PF, Landa, A, Melgoza, G, Montalvo, F, Serrano, H, Riesgo, H, Barkaoui, K, Bixel, A, Burdanov, A, Chen, WP, Chinchilla, P, Collins, KA, Daylan, T, De Wit, J, Delrez, L, Dévora-Pajares, M, Dietrich, J, Dransfield, G, Ducrot, E, Fausnaugh, M, Furlan, E, Gabor, P, Gan, T, Garcia, L, Ghachoui, M, Giacalone, S, Gibbs, AB, Gillon, M, Gnilka, C, Gore, R, Guerrero, N, Henning, T, Hesse, K, Jehin, E, Jenkins, JM, Latham, DW, Lester, K, McCormac, J, Murray, CA, Niraula, P, Pedersen, PP, Queloz, D, Ricker, G, Rodriguez, DR, Schroeder, A, Schwarz, RP, Scott, N, Seager, S, Theissen, CA, Thompson, S, Timmermans, M, Twicken, JD & Winn, JN 2021, 'A large sub-Neptune transiting the thick-disk M4 v TOI-2406', Astronomy and astrophysics, vol. 653, A97. https://doi.org/10.1051/0004-6361/202141277

@article{4e35cac6f1a849428612c0e4832f130d,

title = "A large sub-Neptune transiting the thick-disk M4 v TOI-2406",

abstract = "Context. Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these planets are highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST. Aims. Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. The star's low metallicity and the relatively large size and short period of the planet make TOI-2406 b an unusual outcome of planet formation, and its characterisation provides an important observational constraint for formation models. Methods. We first infer properties of the host star by analysing the star's near-infrared spectrum, spectral energy distribution, and Gaia parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data. Results. We determine the host to be a metal-poor M4 V star, located at a distance of 56 pc, with properties Teff = 3100 ± 75 K, M∗ = 0.162 ± 0.008Mo˙, R∗ = 0.202 ± 0.011Ro˙, and [Fe∕ H] = -0.38 ± 0.07, and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with Rp = 2.94 ± 0.17R⊕ and P= 3.077 d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3σ, prompting questions about the dynamical history of the system. Conclusions. This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy. Although the planet's mass remains to be constrained, we estimate the S/N using amass-radius relationship, ranking the system fifth in the population of large sub-Neptunes, with TOI-2406 b having a much lower equilibrium temperature than other spectroscopically accessible members of this population.",

keywords = "Planets and satellites: detection, Stars: individual: TOI-2406, Techniques: photometric",

author = "Wells, {R. D.} and Rackham, {B. V.} and N. Schanche and R. Petrucci and {G{\'o}mez Maqueo Chew}, Y. and Demory, {B. O.} and Burgasser, {A. J.} and R. Burn and Pozuelos, {F. J.} and G{\"u}nther, {M. N.} and L. Sabin and U. Schroffenegger and G{\'o}mez-Mu{\~n}oz, {M. A.} and Stassun, {K. G.} and {Van Grootel}, V. and Howell, {S. B.} and D. Sebastian and Triaud, {A. H.M.J.} and D. Apai and I. Plauchu-Frayn and Guerrero, {C. A.} and Guill{\'e}n, {P. F.} and A. Landa and G. Melgoza and F. Montalvo and H. Serrano and H. Riesgo and K. Barkaoui and A. Bixel and A. Burdanov and Chen, {W. P.} and P. Chinchilla and Collins, {K. A.} and T. Daylan and {De Wit}, J. and L. Delrez and M. D{\'e}vora-Pajares and J. Dietrich and G. Dransfield and E. Ducrot and M. Fausnaugh and E. Furlan and P. Gabor and T. Gan and L. Garcia and M. Ghachoui and S. Giacalone and Gibbs, {A. B.} and M. Gillon and C. Gnilka and R. Gore and N. Guerrero and T. Henning and K. Hesse and E. Jehin and Jenkins, {J. M.} and Latham, {D. W.} and K. Lester and J. McCormac and Murray, {C. A.} and P. Niraula and Pedersen, {P. P.} and D. Queloz and G. Ricker and Rodriguez, {D. R.} and A. Schroeder and Schwarz, {R. P.} and N. Scott and S. Seager and Theissen, {C. A.} and S. Thompson and M. Timmermans and Twicken, {J. D.} and Winn, {J. N.}",

note = "Publisher Copyright: {\textcopyright} ESO 2021.",

year = "2021",

month = sep,

day = "1",

doi = "10.1051/0004-6361/202141277",

language = "English (US)",

volume = "653",

journal = "Astronomy and astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

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TY - JOUR

T1 - A large sub-Neptune transiting the thick-disk M4 v TOI-2406

AU - Wells, R. D.

AU - Rackham, B. V.

AU - Schanche, N.

AU - Petrucci, R.

AU - Gómez Maqueo Chew, Y.

AU - Demory, B. O.

AU - Burgasser, A. J.

AU - Burn, R.

AU - Pozuelos, F. J.

AU - Günther, M. N.

AU - Sabin, L.

AU - Schroffenegger, U.

AU - Gómez-Muñoz, M. A.

AU - Stassun, K. G.

AU - Van Grootel, V.

AU - Howell, S. B.

AU - Sebastian, D.

AU - Triaud, A. H.M.J.

AU - Apai, D.

AU - Plauchu-Frayn, I.

AU - Guerrero, C. A.

AU - Guillén, P. F.

AU - Landa, A.

AU - Melgoza, G.

AU - Montalvo, F.

AU - Serrano, H.

AU - Riesgo, H.

AU - Barkaoui, K.

AU - Bixel, A.

AU - Burdanov, A.

AU - Chen, W. P.

AU - Chinchilla, P.

AU - Collins, K. A.

AU - Daylan, T.

AU - De Wit, J.

AU - Delrez, L.

AU - Dévora-Pajares, M.

AU - Dietrich, J.

AU - Dransfield, G.

AU - Ducrot, E.

AU - Fausnaugh, M.

AU - Furlan, E.

AU - Gabor, P.

AU - Gan, T.

AU - Garcia, L.

AU - Ghachoui, M.

AU - Giacalone, S.

AU - Gibbs, A. B.

AU - Gillon, M.

AU - Gnilka, C.

AU - Gore, R.

AU - Guerrero, N.

AU - Henning, T.

AU - Hesse, K.

AU - Jehin, E.

AU - Jenkins, J. M.

AU - Latham, D. W.

AU - Lester, K.

AU - McCormac, J.

AU - Murray, C. A.

AU - Niraula, P.

AU - Pedersen, P. P.

AU - Queloz, D.

AU - Ricker, G.

AU - Rodriguez, D. R.

AU - Schroeder, A.

AU - Schwarz, R. P.

AU - Scott, N.

AU - Seager, S.

AU - Theissen, C. A.

AU - Thompson, S.

AU - Timmermans, M.

AU - Twicken, J. D.

AU - Winn, J. N.

PY - 2021/9/1

Y1 - 2021/9/1

N2 - Context. Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these planets are highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST. Aims. Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. The star's low metallicity and the relatively large size and short period of the planet make TOI-2406 b an unusual outcome of planet formation, and its characterisation provides an important observational constraint for formation models. Methods. We first infer properties of the host star by analysing the star's near-infrared spectrum, spectral energy distribution, and Gaia parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data. Results. We determine the host to be a metal-poor M4 V star, located at a distance of 56 pc, with properties Teff = 3100 ± 75 K, M∗ = 0.162 ± 0.008Mo˙, R∗ = 0.202 ± 0.011Ro˙, and [Fe∕ H] = -0.38 ± 0.07, and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with Rp = 2.94 ± 0.17R⊕ and P= 3.077 d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3σ, prompting questions about the dynamical history of the system. Conclusions. This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy. Although the planet's mass remains to be constrained, we estimate the S/N using amass-radius relationship, ranking the system fifth in the population of large sub-Neptunes, with TOI-2406 b having a much lower equilibrium temperature than other spectroscopically accessible members of this population.

AB - Context. Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these planets are highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST. Aims. Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. The star's low metallicity and the relatively large size and short period of the planet make TOI-2406 b an unusual outcome of planet formation, and its characterisation provides an important observational constraint for formation models. Methods. We first infer properties of the host star by analysing the star's near-infrared spectrum, spectral energy distribution, and Gaia parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data. Results. We determine the host to be a metal-poor M4 V star, located at a distance of 56 pc, with properties Teff = 3100 ± 75 K, M∗ = 0.162 ± 0.008Mo˙, R∗ = 0.202 ± 0.011Ro˙, and [Fe∕ H] = -0.38 ± 0.07, and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with Rp = 2.94 ± 0.17R⊕ and P= 3.077 d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3σ, prompting questions about the dynamical history of the system. Conclusions. This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy. Although the planet's mass remains to be constrained, we estimate the S/N using amass-radius relationship, ranking the system fifth in the population of large sub-Neptunes, with TOI-2406 b having a much lower equilibrium temperature than other spectroscopically accessible members of this population.

KW - Planets and satellites: detection

KW - Stars: individual: TOI-2406

KW - Techniques: photometric

UR - http://www.scopus.com/inward/record.url?scp=85114964124&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85114964124&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/202141277

DO - 10.1051/0004-6361/202141277

M3 - Article

SN - 0004-6361

VL - 653

JO - Astronomy and astrophysics

JF - Astronomy and astrophysics

M1 - A97

ER -

A large sub-Neptune transiting the thick-disk M4 v TOI-2406

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