Kavli Affiliate: Andrew Vanderburg
| First 5 Authors: Ryan Cloutier, Michael Greklek-McKeon, Serena Wurmser, Collin Cherubim, Erik Gillis
| Summary:
Is the population of close-in planets orbiting M dwarfs sculpted by thermally
driven escape or is it a direct outcome of the planet formation process? A
number of recent empirical results strongly suggest the latter. However, the
unique architecture of the TOI-1266 system presents a challenge to models of
planet formation and atmospheric escape given its seemingly "inverted"
architecture of a large sub-Neptune ($P_b=10.9$ days, $R_{p,b}=2.62pm 0.11,
mathrm{R}_{oplus}$) orbiting interior to that of the system’s smaller planet
($P_c=18.8$ days, $R_{p,c}=2.13pm 0.12, mathrm{R}_{oplus}$). Here we
present revised planetary radii based on new TESS and diffuser-assisted
ground-based transit observations, and characterize both planetary masses using
a set of 145 radial velocity measurements from HARPS-N ($M_{p,b}=4.23pm 0.69,
mathrm{M}_{oplus}, M_{p,c}=2.88pm 0.80, mathrm{M}_{oplus}$). Our analysis
also reveals a third planet candidate ($P_d=32.3$ days, $M_{p,d}sin{i} =
4.59^{+0.96}_{-0.94}, mathrm{M}_{oplus}$), which if real, would form a chain
of near 5:3 period ratios, although the system is likely not in a mean motion
resonance. Our results indicate that TOI-1266 b and c are among the lowest
density sub-Neptunes around M dwarfs and likely exhibit distinct bulk
compositions of a gas-enveloped terrestrial ($X_{mathrm{env},b}=5.5pm 0.7$%)
and a water-rich world (WMF$_c=59pm 14$%), which is supported by hydrodynamic
escape models. If distinct bulk compositions are confirmed through atmospheric
characterization, the system’s unique architecture would represent an
interesting test case of inside-out sub-Neptune formation at pebble traps.
| Search Query: ArXiv Query: search_query=au:”Andrew Vanderburg”&id_list=&start=0&max_results=3