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

Zhoujian Zhang; Brendan P. Bowler; Trent J. Dupuy; Timothy D. Brandt; G. Mirek Brandt; William D. Cochran; Michael Endl; Phillip J. MacQueen; Kaitlin M. Kratter; Howard T. Isaacson; Kyle Franson; Adam L. Kraus; Caroline V. Morley; Yifan Zhou

doi:10.3847/1538-3881/aca88c

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

Zhoujian Zhang^*, Brendan P. Bowler, Trent J. Dupuy, Timothy D. Brandt, G. Mirek Brandt, William D. Cochran, Michael Endl, Phillip J. MacQueen, Kaitlin M. Kratter, Howard T. Isaacson, Kyle Franson, Adam L. Kraus, Caroline V. Morley, Yifan Zhou

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

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 2.73.3= -+ au), a smaller eccentricity (e = 0.55 ± 0.05), and a more precise inclination (i=85 . 4+0 .3-0.1). 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 BC’s barycentric orbit is likely aligned with those of A’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.

Original language	English
Article number	73
Pages (from-to)	1-18
Number of pages	18
Journal	Astronomical Journal
Volume	165
Issue number	2
DOIs	https://doi.org/10.3847/1538-3881/aca88c
Publication status	Published - 27 Jan 2023

Keywords / Materials (for Non-textual outputs)

Spin-Orbit alignment
Gravitational Instabilities
Planetary system
Binary-systems
Mass
Companion:I
Multiplicity; II
Perturbations

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10.3847/1538-3881/aca88cLicence: Creative Commons: Attribution (CC-BY)

2210.07252v1Accepted author manuscript, 20.9 MBLicence: Creative Commons: Attribution (CC-BY)

https://arxiv.org/abs/2210.07252Licence: Creative Commons: Attribution (CC-BY)

Extending Stellar Astrophysics to Planetary Masses
Dupuy, T. (Principal Investigator)
STFC
1/04/22 → 31/03/25
Project: Research

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Zhang, Z., Bowler, B. P., Dupuy, T. J., Brandt, T. D., Brandt, G. M., Cochran, W. D., Endl, M., MacQueen, P. J., Kratter, K. M., Isaacson, H. T., Franson, K., Kraus, A. L., Morley, C. V., & Zhou, Y. (2023). The McDonald Accelerating Stars Survey: Architecture of the Ancient Five-Planet Host System Kepler-444. Astronomical Journal, 165(2), 1-18. Article 73. https://doi.org/10.3847/1538-3881/aca88c

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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-typespectroscopic 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 fromKeck/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 2.73.3= -+ au), a smaller eccentricity (e = 0.55 ± 0.05), and a more precise inclination (i=85 . 4+0 .3-0.1). 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 format early epochs of the universe and survive their secular evolution throughout cosmic time.",

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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",

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T1 - The McDonald Accelerating Stars Survey: Architecture of the Ancient Five-Planet Host System Kepler-444

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AU - Bowler, Brendan P.

AU - Dupuy, Trent J.

AU - Brandt, Timothy D.

AU - Brandt, G. Mirek

AU - Cochran, William D.

AU - Endl, Michael

AU - MacQueen, Phillip J.

AU - Kratter, Kaitlin M.

AU - Isaacson, Howard T.

AU - Franson, Kyle

AU - Kraus, Adam L.

AU - Morley, Caroline V.

AU - Zhou, Yifan

N1 - AJ in press

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N2 - 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-typespectroscopic 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 fromKeck/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 2.73.3= -+ au), a smaller eccentricity (e = 0.55 ± 0.05), and a more precise inclination (i=85 . 4+0 .3-0.1). 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 BC’s barycentric orbit is likely aligned with those of A’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 format early epochs of the universe and survive their secular evolution throughout cosmic time.

AB - 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-typespectroscopic 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 fromKeck/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 2.73.3= -+ au), a smaller eccentricity (e = 0.55 ± 0.05), and a more precise inclination (i=85 . 4+0 .3-0.1). 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 BC’s barycentric orbit is likely aligned with those of A’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 format early epochs of the universe and survive their secular evolution throughout cosmic time.

KW - Spin-Orbit alignment

KW - Gravitational Instabilities

KW - Planetary system

KW - Binary-systems

KW - Mass

KW - Companion:I

KW - Multiplicity; II

KW - Perturbations

U2 - 10.3847/1538-3881/aca88c

DO - 10.3847/1538-3881/aca88c

M3 - Article

SN - 0004-6256

VL - 165

SP - 1

EP - 18

JO - Astronomical Journal

JF - Astronomical Journal

IS - 2

M1 - 73

ER -

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

Abstract

Keywords / Materials (for Non-textual outputs)

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Extending Stellar Astrophysics to Planetary Masses

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