Edinburgh Research Explorer

TOI-1235 b: a keystone super-Earth for testing radius valley emergence models around early M dwarfs

Research output: Contribution to journalArticle

  • Ryan Cloutier
  • Joseph E. Rodriguez
  • Jonathan Irwin
  • David Charbonneau
  • Keivan G. Stassun
  • Annelies Mortier
  • David W. Latham
  • Howard Isaacson
  • Andrew W. Howard
  • Stéphane Udry
  • Thomas G. Wilson
  • Christopher A. Watson
  • Matteo Pinamonti
  • Florian Lienhard
  • Paolo Giacobbe
  • Pere Guerra
  • Karen A. Collins
  • Allyson Beiryla
  • Gilbert A. Esquerdo
  • Elisabeth Matthews
  • Rachel A. Matson
  • Steve B. Howell
  • Elise Furlan
  • Ian J. M. Crossfield
  • Jennifer G. Winters
  • Chantanelle Nava
  • Kristo Ment
  • Eric D. Lopez
  • George Ricker
  • Roland Vanderspek
  • Sara Seager
  • Jon M. Jenkins
  • Eric B. Ting
  • Peter Tenenbaum
  • Alessandro Sozzetti
  • Lizhou Sha
  • Damien Ségransan
  • Joshua E. Schlieder
  • Dimitar Sasselov
  • Arpita Roy
  • Paul Robertson
  • Ennio Poretti
  • Giampaolo Piotto
  • David Phillips
  • Joshua Pepper
  • Francesco Pepe
  • Emilio Molinari
  • Teo Mocnik
  • Giuseppina Micela
  • Michel Mayor
  • Aldo F. Martinez Fiorenzano
  • Franco Mallia
  • Jack Lubin
  • Christophe Lovis
  • Mercedes López-Morales
  • Molly R. Kosiarek
  • John F. Kielkopf
  • Stephen R. Kane
  • Eric L. N. Jensen
  • Giovanni Isopi
  • Daniel Huber
  • Michelle L. Hill
  • Avet Harutyunyan
  • Erica Gonzales
  • Steven Giacalone
  • Adriano Ghedina
  • Andrea Ercolino
  • Xavier Dumusque
  • Courtney D. Dressing
  • Mario Damasso
  • Paul A. Dalba
  • Rosario Cosentino
  • Dennis M. Conti
  • Knicole D. Colón
  • Kevin I. Collins
  • Andrew Collier Cameron
  • David Ciardi
  • Jessie Christiansen
  • Ashley Chontos
  • Massimo Cecconi
  • Douglas A. Caldwell
  • Christopher Burke
  • Lars Buchhave
  • Charles Beichman
  • Aida Behmard
  • Corey Beard
  • Joseph M. Akana Murphy

Related Edinburgh Organisations

Original languageEnglish
JournalAstronomical Journal
Issue number1
Publication statusPublished - 12 Jun 2020


Small planets on close-in orbits tend to exhibit envelope mass fractions of either effectively zero or up to a few percent depending on their size and orbital period. Models of thermally-driven atmospheric mass loss and of terrestrial planet formation in a gas-poor environment make distinct predictions regarding the location of this rocky/non-rocky transition in period-radius space. Here we present the confrmation of TOI-1235 b (P = 3:44 days, rp = 1:738+0:087 -0:076 R⊕), a planet whose size and period are intermediate between the competing model predictions thus making the system an important test case for emergence models of the rocky/non-rocky transition around early M dwarfs (Rs = 0:630 ± 0:015 RΘ, Ms = 0:640 ± 0:016 MΘ). We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial-velocities from HARPS-N and HIRES. We measure a planet mass of 6:91+0:75-0:85 M⊕, which implies an iron core mass fraction of 20+15-12% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like and we constrain a H/He envelope mass fraction to be < 0:5% at 90% confidence. Our results are consistent with model predictions from thermally-driven atmospheric mass loss but not with gas-poor formation, suggesting that the former class of processes remain effocient at sculpting close-in planets around early M dwarfs. Our RV analysis also reveals a strong periodicity close to the first harmonic of the photometrically-determined stellar rotation period that we treat as stellar activity, despite other lines of evidence favoring a planetary origin (P = 21:8+0:9-0:8 days, mp sin i = 13:0+3:8-5:3 M⊕) that cannot be firmly ruled out by our data.

    Research areas

  • astro-ph.EP, astro-ph.SR

ID: 154913286