@article{fc5f662dca364b9aa3c7b5e5d1b01fef,
title = "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{\textquoteright}s relative astrometry using the adaptive optics imaging from Keck/NIRC2 and Kepler-444 A{\textquoteright}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{\textquoteright}s barycenter. These data greatly extend the time baseline of the monitoring and lead to significant updates to BC{\textquoteright}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{\textquoteright}s protoplanetary disk was likely truncated by BC to a radius of ≈8 au, which resolves the previously noticed tension between Kepler-444 A{\textquoteright}s disk mass and planet masses. Kepler-444 BC{\textquoteright}s barycentric orbit is likely aligned with those of A{\textquoteright}s five planets, which might be primordial or a consequence of dynamical evolution. The Kepler-444 system demonstrates that compact multiplanet systems residing in hierarchical stellar triples can form at early epochs of the universe and survive their secular evolution throughout cosmic time.",
author = "Zhoujian Zhang and Bowler, {Brendan P.} and Dupuy, {Trent J.} and Brandt, {Timothy D.} and Brandt, {G. Mirek} and Cochran, {William D.} and Michael Endl and MacQueen, {Phillip J.} and Kratter, {Kaitlin M.} and Isaacson, {Howard T.} and Kyle Franson and Kraus, {Adam L.} and Morley, {Caroline V.} and Yifan Zhou",
note = "Funding Information: Z.Z. thanks Benjamin Tofflemire and Songhu Wang for helpful discussions. Support for this work was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51522.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. B.P.B. acknowledges support from the National Science Foundation grant AST-1909209, NASA Exoplanet Research Program grant 20-XRP20_2-0119, and the Alfred P. Sloan Foundation. This work was supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. The data presented herein were in part obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. The Hobby-Eberly Telescope (HET) is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universit{\"a}t M{\"u}nchen, and Georg-August-Universit{\"a}t G{\"o}ttingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. This research has made use of the Spanish Virtual Observatory (https://svo.cab.inta-csic.es) project funded by MCIN/AEI/10.13039/501100011033/ through grant PID2020-112949GB-I00. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising from this submission. Funding Information: Z.Z. thanks Benjamin Tofflemire and Songhu Wang for helpful discussions. Support for this work was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51522.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. B.P.B. acknowledges support from the National Science Foundation grant AST-1909209, NASA Exoplanet Research Program grant 20-XRP20_2-0119, and the Alfred P. Sloan Foundation. This work was supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. The data presented herein were in part obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration. The Hobby-Eberly Telescope (HET) is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximilians-Universit{\"a}t M{\"u}nchen, and Georg-August-Universit{\"a}t G{\"o}ttingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. This research has made use of the Spanish Virtual Observatory ( https://svo.cab.inta-csic.es ) project funded by MCIN/AEI/10.13039/501100011033/ through grant PID2020-112949GB-I00. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) license to any Author Accepted Manuscript version arising from this submission. Publisher Copyright: {\textcopyright} 2023. The Author(s). Published by the American Astronomical Society.",
year = "2023",
month = feb,
day = "1",
doi = "10.3847/1538-3881/aca88c",
language = "English (US)",
volume = "165",
journal = "Astronomical Journal",
issn = "0004-6256",
publisher = "IOP Publishing Ltd.",
number = "2",
}