학술논문
TOI-1235 b: a keystone super-Earth for testing radius valley emergence models around early M dwarfs
Document Type
Working Paper
Author
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; Fiorenzano, Aldo F. Martinez; 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; Murphy, Joseph M. Akana
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Subject
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Abstract
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 confirmation of TOI-1235 b ($P=3.44$ days, $r_p=1.738^{+0.087}_{-0.076}$ R$_{\oplus}$), 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 ($R_s=0.630\pm 0.015$ R$_{\odot}$, $M_s=0.640\pm 0.016$ M$_{\odot}$). 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$_{\oplus}$, 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 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 ($P=21.8^{+0.9}_{-0.8}$ days, $m_p\sin{i}=13.0^{+3.8}_{-5.3}$ M$_{\oplus}$) that cannot be firmly ruled out by our data.
Comment: Accepted to The Astronomical Journal. 8 figures & 5 tables. Table 2 is provided in the arXiv source code
Comment: Accepted to The Astronomical Journal. 8 figures & 5 tables. Table 2 is provided in the arXiv source code