TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley

Ryan Cloutier; David Charbonneau; Keivan G. Stassun; Felipe Murgas; Annelies Mortier; Robert Massey; Jack J. Lissauer; David W. Latham; Jonathan Irwin; Raphaëlle D. Haywood; Pere Guerra; Eric Girardin; Steven A. Giacalone; Pau Bosch-Cabot; Allyson Bieryla; Joshua Winn; Christopher A. Watson; Roland Vanderspek; Stéphane Udry; Motohide Tamura; Alessandro Sozzetti; Avi Shporer; Damien Ségransan; Sara Seager; Arjun B. Savel; Dimitar Sasselov; Mark Rose; George Ricker; Ken Rice; Elisa V. Quintana; Samuel N. Quinn; Giampaolo Piotto; David Phillips; Francesco Pepe; Marco Pedani; Hannu Parviainen; Enric Palle; Norio Narita; Emilio Molinari; Giuseppina Micela; Scott Mcdermott; Michel Mayor; Rachel A. Matson; Aldo F. Martinez fiorenzano; Christophe Lovis; Mercedes López-Morales; Nobuhiko Kusakabe; Eric L. N. Jensen; Jon M. Jenkins; Chelsea X. Huang; Steve B. Howell; Avet Harutyunyan; Gábor Fűrész; Akihiko Fukui; Gilbert A. Esquerdo; Emma Esparza-Borges; Xavier Dumusque; Courtney D. Dressing; Luca Di Fabrizio; Karen A. Collins; Andrew Collier Cameron; Jessie L. Christiansen; Massimo Cecconi; Lars A. Buchhave; Walter Boschin; Gloria Andreuzzi

doi:10.3847/1538-3881/ac0157

TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley

Ryan Cloutier^*, David Charbonneau, Keivan G. Stassun, Felipe Murgas, Annelies Mortier, Robert Massey, Jack J. Lissauer, David W. Latham, Jonathan Irwin, Raphaëlle D. Haywood, Pere Guerra, Eric Girardin, Steven A. Giacalone, Pau Bosch-Cabot, Allyson Bieryla, Joshua Winn, Christopher A. Watson, Roland Vanderspek, Stéphane Udry, Motohide TamuraAlessandro Sozzetti, Avi Shporer, Damien Ségransan, Sara Seager, Arjun B. Savel, Dimitar Sasselov, Mark Rose, George Ricker, Ken Rice, Elisa V. Quintana, Samuel N. Quinn, Giampaolo Piotto, David Phillips, Francesco Pepe, Marco Pedani, Hannu Parviainen, Enric Palle, Norio Narita, Emilio Molinari, Giuseppina Micela, Scott Mcdermott, Michel Mayor, Rachel A. Matson, Aldo F. Martinez fiorenzano, Christophe Lovis, Mercedes López-Morales, Nobuhiko Kusakabe, Eric L. N. Jensen, Jon M. Jenkins, Chelsea X. Huang, Steve B. Howell, Avet Harutyunyan, Gábor Fűrész, Akihiko Fukui, Gilbert A. Esquerdo, Emma Esparza-Borges, Xavier Dumusque, Courtney D. Dressing, Luca Di Fabrizio, Karen A. Collins, Andrew Collier Cameron, Jessie L. Christiansen, Massimo Cecconi, Lars A. Buchhave, Walter Boschin, Gloria Andreuzzi

^*Corresponding author for this work

Physics and Astronomy

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

Abstract

Studies of close-in planets orbiting M dwarfs have suggested that the M-dwarf radius valley may be well explained by distinct formation timescales between enveloped terrestrials and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally driven mass-loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M-dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short-period planet TOI-1634 b (P = 0.989 days, $F=121{F}_{\oplus }$, ${r}_{p}={1.790}_{-0.081}^{+0.080}$ R⊕) orbiting a nearby M2 dwarf (Ks = 8.7, Rs = 0.450 R⊙, Ms = 0.502 M⊙) and whose size and orbital period sit within the M-dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of ${4.91}_{-0.70}^{+0.68}$ M⊕, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma $ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky composition that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of Earth supports the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with ${M}_{s}\lesssim 0.5$ M⊙.

Original language	English
Article number	79
Number of pages	21
Journal	The Astronomical Journal
Volume	162
Issue number	2
DOIs	https://doi.org/10.3847/1538-3881/ac0157
Publication status	Published - 1 Aug 2021

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Cloutier, R., Charbonneau, D., Stassun, K. G., Murgas, F., Mortier, A., Massey, R., Lissauer, J. J., Latham, D. W., Irwin, J., Haywood, R. D., Guerra, P., Girardin, E., Giacalone, S. A., Bosch-Cabot, P., Bieryla, A., Winn, J., Watson, C. A., Vanderspek, R., Udry, S., ... Andreuzzi, G. (2021). TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley. The Astronomical Journal, 162(2), Article 79. https://doi.org/10.3847/1538-3881/ac0157

@article{6691d1ddc3e04c28bae880ebfc37b619,

title = "TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley",

abstract = "Studies of close-in planets orbiting M dwarfs have suggested that the M-dwarf radius valley may be well explained by distinct formation timescales between enveloped terrestrials and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally driven mass-loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M-dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short-period planet TOI-1634 b (P = 0.989 days, $F=121{F}_{\oplus }$, ${r}_{p}={1.790}_{-0.081}^{+0.080}$ R⊕) orbiting a nearby M2 dwarf (Ks = 8.7, Rs = 0.450 R⊙, Ms = 0.502 M⊙) and whose size and orbital period sit within the M-dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of ${4.91}_{-0.70}^{+0.68}$ M⊕, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma $ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky composition that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of Earth supports the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with ${M}_{s}\lesssim 0.5$ M⊙.",

author = "Ryan Cloutier and David Charbonneau and Stassun, {Keivan G.} and Felipe Murgas and Annelies Mortier and Robert Massey and Lissauer, {Jack J.} and Latham, {David W.} and Jonathan Irwin and Haywood, {Rapha{\"e}lle D.} and Pere Guerra and Eric Girardin and Giacalone, {Steven A.} and Pau Bosch-Cabot and Allyson Bieryla and Joshua Winn and Watson, {Christopher A.} and Roland Vanderspek and St{\'e}phane Udry and Motohide Tamura and Alessandro Sozzetti and Avi Shporer and Damien S{\'e}gransan and Sara Seager and Savel, {Arjun B.} and Dimitar Sasselov and Mark Rose and George Ricker and Ken Rice and Quintana, {Elisa V.} and Quinn, {Samuel N.} and Giampaolo Piotto and David Phillips and Francesco Pepe and Marco Pedani and Hannu Parviainen and Enric Palle and Norio Narita and Emilio Molinari and Giuseppina Micela and Scott Mcdermott and Michel Mayor and Matson, {Rachel A.} and {Martinez fiorenzano}, {Aldo F.} and Christophe Lovis and Mercedes L{\'o}pez-Morales and Nobuhiko Kusakabe and Jensen, {Eric L. N.} and Jenkins, {Jon M.} and Huang, {Chelsea X.} and Howell, {Steve B.} and Avet Harutyunyan and G{\'a}bor F{\H u}r{\'e}sz and Akihiko Fukui and Esquerdo, {Gilbert A.} and Emma Esparza-Borges and Xavier Dumusque and Dressing, {Courtney D.} and Fabrizio, {Luca Di} and Collins, {Karen A.} and Cameron, {Andrew Collier} and Christiansen, {Jessie L.} and Massimo Cecconi and Buchhave, {Lars A.} and Walter Boschin and Gloria Andreuzzi",

year = "2021",

month = aug,

day = "1",

doi = "10.3847/1538-3881/ac0157",

language = "English",

volume = "162",

journal = "The Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "2",

}

Cloutier, R, Charbonneau, D, Stassun, KG, Murgas, F, Mortier, A, Massey, R, Lissauer, JJ, Latham, DW, Irwin, J, Haywood, RD, Guerra, P, Girardin, E, Giacalone, SA, Bosch-Cabot, P, Bieryla, A, Winn, J, Watson, CA, Vanderspek, R, Udry, S, Tamura, M, Sozzetti, A, Shporer, A, Ségransan, D, Seager, S, Savel, AB, Sasselov, D, Rose, M, Ricker, G, Rice, K, Quintana, EV, Quinn, SN, Piotto, G, Phillips, D, Pepe, F, Pedani, M, Parviainen, H, Palle, E, Narita, N, Molinari, E, Micela, G, Mcdermott, S, Mayor, M, Matson, RA, Martinez fiorenzano, AF, Lovis, C, López-Morales, M, Kusakabe, N, Jensen, ELN, Jenkins, JM, Huang, CX, Howell, SB, Harutyunyan, A, Fűrész, G, Fukui, A, Esquerdo, GA, Esparza-Borges, E, Dumusque, X, Dressing, CD, Fabrizio, LD, Collins, KA, Cameron, AC, Christiansen, JL, Cecconi, M, Buchhave, LA, Boschin, W & Andreuzzi, G 2021, 'TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley', The Astronomical Journal, vol. 162, no. 2, 79. https://doi.org/10.3847/1538-3881/ac0157

TY - JOUR

T1 - TOI-1634 b

T2 - An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley

AU - Cloutier, Ryan

AU - Charbonneau, David

AU - Stassun, Keivan G.

AU - Murgas, Felipe

AU - Mortier, Annelies

AU - Massey, Robert

AU - Lissauer, Jack J.

AU - Latham, David W.

AU - Irwin, Jonathan

AU - Haywood, Raphaëlle D.

AU - Guerra, Pere

AU - Girardin, Eric

AU - Giacalone, Steven A.

AU - Bosch-Cabot, Pau

AU - Bieryla, Allyson

AU - Winn, Joshua

AU - Watson, Christopher A.

AU - Vanderspek, Roland

AU - Udry, Stéphane

AU - Tamura, Motohide

AU - Sozzetti, Alessandro

AU - Shporer, Avi

AU - Ségransan, Damien

AU - Seager, Sara

AU - Savel, Arjun B.

AU - Sasselov, Dimitar

AU - Rose, Mark

AU - Ricker, George

AU - Rice, Ken

AU - Quintana, Elisa V.

AU - Quinn, Samuel N.

AU - Piotto, Giampaolo

AU - Phillips, David

AU - Pepe, Francesco

AU - Pedani, Marco

AU - Parviainen, Hannu

AU - Palle, Enric

AU - Narita, Norio

AU - Molinari, Emilio

AU - Micela, Giuseppina

AU - Mcdermott, Scott

AU - Mayor, Michel

AU - Matson, Rachel A.

AU - Martinez fiorenzano, Aldo F.

AU - Lovis, Christophe

AU - López-Morales, Mercedes

AU - Kusakabe, Nobuhiko

AU - Jensen, Eric L. N.

AU - Jenkins, Jon M.

AU - Huang, Chelsea X.

AU - Howell, Steve B.

AU - Harutyunyan, Avet

AU - Fűrész, Gábor

AU - Fukui, Akihiko

AU - Esquerdo, Gilbert A.

AU - Esparza-Borges, Emma

AU - Dumusque, Xavier

AU - Dressing, Courtney D.

AU - Fabrizio, Luca Di

AU - Collins, Karen A.

AU - Cameron, Andrew Collier

AU - Christiansen, Jessie L.

AU - Cecconi, Massimo

AU - Buchhave, Lars A.

AU - Boschin, Walter

AU - Andreuzzi, Gloria

PY - 2021/8/1

Y1 - 2021/8/1

N2 - Studies of close-in planets orbiting M dwarfs have suggested that the M-dwarf radius valley may be well explained by distinct formation timescales between enveloped terrestrials and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally driven mass-loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M-dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short-period planet TOI-1634 b (P = 0.989 days, $F=121{F}_{\oplus }$, ${r}_{p}={1.790}_{-0.081}^{+0.080}$ R⊕) orbiting a nearby M2 dwarf (Ks = 8.7, Rs = 0.450 R⊙, Ms = 0.502 M⊙) and whose size and orbital period sit within the M-dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of ${4.91}_{-0.70}^{+0.68}$ M⊕, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma $ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky composition that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of Earth supports the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with ${M}_{s}\lesssim 0.5$ M⊙.

AB - Studies of close-in planets orbiting M dwarfs have suggested that the M-dwarf radius valley may be well explained by distinct formation timescales between enveloped terrestrials and rocky planets that form at late times in a gas-depleted environment. This scenario is at odds with the picture that close-in rocky planets form with a primordial gaseous envelope that is subsequently stripped away by some thermally driven mass-loss process. These two physical scenarios make unique predictions of the rocky/enveloped transition's dependence on orbital separation such that studying the compositions of planets within the M-dwarf radius valley may be able to establish the dominant physics. Here, we present the discovery of one such keystone planet: the ultra-short-period planet TOI-1634 b (P = 0.989 days, $F=121{F}_{\oplus }$, ${r}_{p}={1.790}_{-0.081}^{+0.080}$ R⊕) orbiting a nearby M2 dwarf (Ks = 8.7, Rs = 0.450 R⊙, Ms = 0.502 M⊙) and whose size and orbital period sit within the M-dwarf radius valley. We confirm the TESS-discovered planet candidate using extensive ground-based follow-up campaigns, including a set of 32 precise radial velocity measurements from HARPS-N. We measure a planetary mass of ${4.91}_{-0.70}^{+0.68}$ M⊕, which makes TOI-1634 b inconsistent with an Earth-like composition at $5.9\sigma $ and thus requires either an extended gaseous envelope, a large volatile-rich layer, or a rocky composition that is not dominated by iron and silicates to explain its mass and radius. The discovery that the bulk composition of TOI-1634 b is inconsistent with that of Earth supports the gas-depleted formation mechanism to explain the emergence of the radius valley around M dwarfs with ${M}_{s}\lesssim 0.5$ M⊙.

U2 - 10.3847/1538-3881/ac0157

DO - 10.3847/1538-3881/ac0157

M3 - Article

SN - 0004-6256

VL - 162

JO - The Astronomical Journal

JF - The Astronomical Journal

IS - 2

M1 - 79

ER -

TOI-1634 b: An Ultra-short-period Keystone Planet Sitting inside the M-dwarf Radius Valley

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