The McDonald Accelerating Stars Survey: Architecture of the Ancient Five-planet Host System Kepler-444
Abstract

We present the latest and most precise characterization of the architecture for the ancient (≈11 Gyr) Kepler-444 system, which is composed of a K0 primary star (Kepler-444 A) hosting five transiting planets and a tight M-type spectroscopic binary (Kepler-444 BC) with an A–BC projected separation of 66 au. We have measured the system’s relative astrometry using the adaptive optics imaging from Keck/NIRC2 and Kepler-444 A’s radial velocities from the Hobby-Eberly Telescope and reanalyzed relative radial velocities between BC and A from Keck/HIRES. We also include the Hipparcos-Gaia astrometric acceleration and all published astrometry and radial velocities in an updated orbit analysis of BC’s barycenter. These data greatly extend the time baseline of the monitoring and lead to significant updates to BC’s barycentric orbit compared to previous work, including a larger semimajor axis ($a=52.2−2.7+3.3$au), a smaller eccentricity (e= 0.55 ± 0.05), and a more precise inclination ($i=85.°4−0.°4+0.°3$). We have also derived the first dynamical masses of B and C components. Our results suggest that Kepler-444 A’s protoplanetary disk was likely truncated by BC to a radius of ≈8 au, which resolves the previously noticed tension between Kepler-444 A’s disk mass and planet masses. Kepler-444 more »

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
NSF-PAR ID:
10393317
Journal Name:
The Astronomical Journal
Volume:
165
Issue:
2
Page Range or eLocation-ID:
Article No. 73
ISSN:
0004-6256
Publisher:
DOI PREFIX: 10.3847
National Science Foundation
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