TOI-1670 b and c: An Inner Sub-Neptune with an Outer Warm Jupiter Unlikely to Have Originated from High-eccentricity Migration
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Tran_2022_AJ_163_225.pdf
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Published version
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2.64 MB
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Adobe PDF
Checksum (MD5)
21894911768761b88e8e4a2dfea09f85
Author(s)
Seager, Sara
Date Issued
2022
Journal
Astronomical Journal
Publisher
American Astronomical Society
Citation
Seager, Sara. 2022. "TOI-1670 b and c: An Inner Sub-Neptune with an Outer Warm Jupiter Unlikely to Have Originated from High-eccentricity Migration." Astronomical Journal, 163 (5).
Version
Final published version
Abstract
We report the discovery of two transiting planets around the bright (V = 9.9 mag) main-sequence F7 star TOI-1670 by the Transiting Exoplanet Survey Satellite. TOI-1670 b is a sub-Neptune (${R}_{{\rm{b}}}={2.06}_{-0.15}^{+0.19}$ R⊕) on a 10.9 day orbit, and TOI-1670 c is a warm Jupiter (${R}_{{\rm{c}}}={0.987}_{-0.025}^{+0.025}$ RJup) on a 40.7 day orbit. Using radial velocity observations gathered with the Tull Coudé Spectrograph on the Harlan J. Smith telescope and HARPS-N on the Telescopio Nazionale Galileo, we find a planet mass of ${M}_{{\rm{c}}}={0.63}_{-0.08}^{+0.09}$ MJup for the outer warm Jupiter, implying a mean density of ${\rho }_{c}={0.81}_{-0.11}^{+0.13}$ g cm−3. The inner sub-Neptune is undetected in our radial velocity data (Mb < 0.13 MJup at the 99% confidence level). Multiplanet systems like TOI-1670 hosting an outer warm Jupiter on a nearly circular orbit (${e}_{{\rm{c}}}={0.09}_{-0.04}^{+0.05}$) and one or more inner coplanar planets are more consistent with "gentle" formation mechanisms such as disk migration or in situ formation rather than high-eccentricity migration. Of the 11 known systems with a warm Jupiter and a smaller inner companion, eight (73%) are near a low-order mean-motion resonance, which can be a signature of migration. TOI-1670 joins two other systems (27% of this subsample) with period commensurabilities greater than 3, a common feature of in situ formation or halted inward migration. TOI-1670 and the handful of similar systems support a diversity of formation pathways for warm Jupiters.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.3847/1538-3881/AC5C4F
