TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs
Author(s)Cloutier, Ryan; Rodriguez, Joseph E.; Irwin, Jonathan; Charbonneau, David; Stassun, Keivan G.; Mortier, Annelies; Latham, David W.; Isaacson, Howard; Howard, Andrew W.; Udry, Stéphane; Wilson, Thomas G.; Watson, Christopher A.; Pinamonti, Matteo; Lienhard, Florian; Giacobbe, Paolo; Guerra, Pere; Collins, Karen A.; Beiryla, Allyson; Esquerdo, Gilbert A.; Matthews, Elisabeth; Matson, Rachel A.; Howell, Steve B.; Furlan, Elise; Crossfield, Ian J. M.; Winters, Jennifer G.; Nava, Chantanelle; Ment, Kristo; Lopez, Eric D.; Ricker, George; Vanderspek, Roland; Seager, Sara; Jenkins, Jon M.; Ting, Eric B.; Tenenbaum, Peter; Sozzetti, Alessandro; Sha, Lizhou; Ségransan, Damien; Schlieder, Joshua E.; Sasselov, Dimitar; Roy, Arpita; Robertson, Paul; Rice, Ken; Poretti, Ennio; Piotto, Giampaolo; Phillips, David; Pepper, Joshua; Pepe, Francesco; Molinari, Emilio; Mocnik, Teo; Micela, Giuseppina; Mayor, Michel; Martinez Fiorenzano, Aldo F.; Mallia, Franco; Lubin, Jack; Lovis, Christophe; López-Morales, Mercedes; Kosiarek, Molly R.; Kielkopf, John F.; Kane, Stephen R.; Jensen, Eric L. N.; Isopi, Giovanni; Huber, Daniel; Hill, Michelle L.; Harutyunyan, Avet; Gonzales, Erica; Giacalone, Steven; Ghedina, Adriano; Ercolino, Andrea; Dumusque, Xavier; Dressing, Courtney D.; Damasso, Mario; Dalba, Paul A.; Cosentino, Rosario; Conti, Dennis M.; Colón, Knicole D.; Collins, Kevin I.; Cameron, Andrew Collier; Ciardi, David; Christiansen, Jessie; Chontos, Ashley; Cecconi, Massimo; Caldwell, Douglas A.; Burke, Christopher; Buchhave, Lars; Beichman, Charles; Behmard, Aida; Beard, Corey; Akana Murphy, Joseph M.; ... Show more Show less
MetadataShow full item record
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/nonrocky transition in period-radius space. Here we present the confirmation of TOI-1235 b (P = 3.44 days, rp1.738-0.076+0.087 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/nonrocky transition around early M dwarfs (R s = 0.630± 0.015 ⊕, M s = 0.640 ± 0.016 ⊙. We confirm the TESS planet discovery using reconnaissance spectroscopy, ground-based photometry, high-resolution imaging, and a set of 38 precise radial velocities (RVs) from HARPS-N and HIRES. We measure a planet mass of 6.91-0.85+0.75M⊕ which implies an iron core mass fraction of 20-12+15% in the absence of a gaseous envelope. The bulk composition of TOI-1235 b is therefore consistent with being Earth-like, and we constrain an 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 remains efficient 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+0.9-0.8days,mp sin =13.0+ 3.8-5.3M⊕) that cannot be firmly ruled out by our data.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences; MIT Kavli Institute for Astrophysics and Space Research
American Astronomical Society
Cloutier, Ryan et al. "TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs." Astronomical Journal 160, 1 (June 2020): dx.doi.org/10.3847/1538-3881/ab9534 © 2020 American Astronomical Society
Final published version