TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs

Media type: E-Article
Title: TOI-1235 b: A Keystone Super-Earth for Testing Radius Valley Emergence Models around Early M Dwarfs
Contributor: 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.; [...]
imprint: American Astronomical Society, 2020
Published in: The Astronomical Journal
Language: Not determined
DOI: 10.3847/1538-3881/ab9534
ISSN: 0004-6256; 1538-3881
Keywords: Space and Planetary Science ; Astronomy and Astrophysics
Origination:
Footnote:
Description: <jats:title>Abstract</jats:title> <jats:p>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 (<jats:italic>P</jats:italic> = 3.44 days, <jats:inline-formula> <jats:tex-math> <?CDATA ${r}_{{\rm{p}}}={1.738}_{-0.076}^{+0.087}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> <jats:inline-formula> <jats:tex-math> <?CDATA ${R}_{\oplus }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn2.gif" xlink:type="simple" /> </jats:inline-formula>), 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 (<jats:italic>R</jats:italic> <jats:sub>s</jats:sub> = 0.630 ± 0.015 <jats:inline-formula> <jats:tex-math> <?CDATA ${R}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn3.gif" xlink:type="simple" /> </jats:inline-formula>, <jats:italic>M</jats:italic> <jats:sub>s</jats:sub> = 0.640 ± 0.016 <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\odot }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn4.gif" xlink:type="simple" /> </jats:inline-formula>). 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 <jats:inline-formula> <jats:tex-math> <?CDATA ${6.91}_{-0.85}^{+0.75}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn5.gif" xlink:type="simple" /> </jats:inline-formula> <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\oplus }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn6.gif" xlink:type="simple" /> </jats:inline-formula>, which implies an iron core mass fraction of <jats:inline-formula> <jats:tex-math> <?CDATA ${20}_{-12}^{+15}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn7.gif" xlink:type="simple" /> </jats:inline-formula>% 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 (<jats:inline-formula> <jats:tex-math> <?CDATA $P={21.8}_{-0.8}^{+0.9}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn8.gif" xlink:type="simple" /> </jats:inline-formula> days, <jats:inline-formula> <jats:tex-math> <?CDATA ${m}_{{\rm{p}}}\sin i={13.0}_{-5.3}^{+3.8}$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn9.gif" xlink:type="simple" /> </jats:inline-formula> <jats:inline-formula> <jats:tex-math> <?CDATA ${M}_{\oplus }$?> </jats:tex-math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="ajab9534ieqn10.gif" xlink:type="simple" /> </jats:inline-formula>) that cannot be firmly ruled out by our data.</jats:p>
Access State: Open Access

Search in field:

Recently searched for: