J/AJ/170/147 Mass-separation constraints for HWO target systems (Painter+, 2025)
Astrometric accelerations of provisional targets for the Habitable Worlds
Observatory.
Painter K.E., Bowler B.P., Franson K., Becker J.C., Burt J.A.
<Astron. J., 170, 147 (2025)>
=2025AJ....170..147P 2025AJ....170..147P
ADC_Keywords: Exoplanets; Positional data; Proper motions; Stars, masses;
Optical; Stars, double and multiple
Keywords: Astrometric exoplanet detection ; Exoplanets ; Habitable planets ;
Space telescopes ; Astrometric binary stars
Abstract:
NASA's Habitable Worlds Observatory (HWO) will be the first space
telescope capable of directly imaging Earth-like planets in the
habitable zones (HZs) of Sun-like stars to probe their atmospheres for
signs of life. Now in its early stages of design, a list of the 164
most promising targets for HWO has been released to the community to
carry out precursor science. Massive companions in these
systems-stars, brown dwarfs, or giant planets-could preclude the
existence of Earth-sized planets in the HZ by impacting their
long-term dynamical stability. Here, we use astrometry from Hipparcos
and Gaia Early Data Release 3 (EDR3) to identify stars in the HWO
preliminary target list that exhibit astrometric accelerations and
determine joint constraints on the expected mass and separation of
these companions. We find that 54 HWO targets have significant
astrometric accelerations, 37 of which are accounted for by known
giant planets and stellar companions. Follow-up efforts are required
to clarify the specific nature of the suspected companions around the
remaining 17 accelerating stars. Stars without significant
accelerations are used to rule out large regions of companion mass and
separation down to planetary masses. We find that with Hipparcos and
Gaia EDR3 we are ∼85% sensitive to 2MJup planets between 4 and 10AU.
Future Gaia releases will provide sensitivity to sub-Jovian-mass
planets on solar system scales for provisional HWO targets. Finally,
using analytical estimates of dynamical stability, we find that 13 HWO
targets have known stellar or planetary companions that are likely to
disrupt HZ planets.
Description:
We use the Hipparcos-Gaia Catalog of Accelerations (HGCA;
Brandt+2021, J/ApJS/254/42), along with a semi-analytical modeling
framework adapted from Kervella+2019 (J/A+A/623/A72) and
Kervella+2022 (J/A+A/657/A7), to constrain the existence of new and
previously known companions spanning 3 orders of magnitude in mass and
separation in the Habitable Worlds Observatory (HWO) target systems.
Here, we crossmatch the list of 164 targets from
Mamajek+ (2023AAS...24111607M 2023AAS...24111607M) with the Hipparcos-Gaia Catalog of
Accelerations (HGCA; Brandt+2021, J/ApJS/254/42), which provides
proper motion differences (long-term accelerations) between the
Hipparcos (1997, I/239; 2007, I/311) and Gaia (EDR3, I/350; DR3, I/355)
missions for over 100,000 stars. Of the 164 targets from Mamajek+2023,
156 have entries in the HGCA catalog. With the ∼25yr time baseline
between Hipparcos and Gaia, these accelerations indicate the presence
of giant planets, brown dwarfs, and stellar companions on wide orbits
(∼1-100AU) in these systems.
The Habitable Worlds Observatory (HWO) is a planned NASA flagship
space telescope with the primary goal of searching for biosignatures
on terrestrial planets in the habitable zones (HZs) of nearby Sun-like
stars. It will be a large infrared/optical/ultraviolet observatory
capable of performing a wide range of astrophysics programs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
targets.dat 16 156 List of targets (added by CDS)
table4.dat 61 54000 Joint mass-separation constraints for stars with
astrometric accelerations
table5.dat 49 102000 Upper limits for stars without astrometric
accelerations
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-)
III/117 : MK Classifications of Close Visual Binaries (Corbally, 1984)
III/150A : Perkins Revised MK Types for the Cooler Stars (Keenan+ 1989)
II/215 : uvby-beta Catalogue (Hauck+ 1997)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/AJ/126/2048 : NStars project: the Northern Sample. I. (Gray+, 2003)
J/A+A/410/1051 : ELODIE surv. for north. extra-solar planets. II. (Naef+, 2003)
J/AJ/132/161 : NStars project: The southern sample. I. (Gray+, 2006)
J/A+A/577/A128 : CARMENES input cat. of M dwarfs. I (Alonso-Floriano+, 2015)
J/ApJ/809/8 : Terrestr. planet occurrence rates for KOI stars (Burke+, 2015)
J/A+A/584/A72 : A transiting rocky planet at 6.5pc from Sun (Motalebi+ 2015)
J/MNRAS/449/3160 : Stellar multiplicity and debris discs (Rodriguez+, 2015)
J/ApJ/821/74 : 27yr of RV observations of HD 219134 (Johnson+, 2016)
J/ApJS/224/36 : The AllWISE motion survey (AllWISE2) (Kirkpatrick+, 2016)
J/AJ/152/8 : Impact of stellar multipl. on planetary syst. I. (Kraus+, 2016)
J/AJ/153/208 : LCES HIRES/Keck radial velocity Exoplanet Survey (Butler+, 2017)
J/A+A/619/L10 : pi Men radial velocity curves (Gandolfi+, 2018)
J/A+A/623/A72 : Binar. of Hipparcos stars: Gaia pm anomaly (Kervella+, 2019)
J/ApJ/871/63 : How to constrain your M dwarf. II. Nearby binaries (Mann+, 2019)
J/AJ/157/33 : Radial velocity exploration of ε Eridani (Mawet+, 2019)
J/AJ/158/13 : The first 300 stars observed by the GPIES (Nielsen+, 2019)
J/ApJS/254/42 : Hipparcos-Gaia (EDR3) Catalog of Accelerations (Brandt, 2021)
J/AJ/161/36 : 117 exoplanets in habitable zone with Kepler DR25 (Bryson+, 2021)
J/AJ/161/134 : Survey of stellar & planetary comp. within 25pc (Hirsch+, 2021)
J/AJ/162/181 : RV & Hipparcos positions of epsilon Eridani (Llop-sayson+, 2021)
J/AJ/162/53 : Speckle interferometry at the USNO. XXIV. (Mason+, 2021)
J/ApJS/255/8 : The California Legacy Survey. I. Planet cat. (Rosenthal+, 2021)
J/AJ/161/144 : Inner & outer orbits in 13 mult. stars syst. (Tokovinin, 2021)
J/AJ/163/288 : Absolute & relative astrom. for ε Indi B (Chen+, 2022)
J/ApJS/262/21 : 3-D selection of 167 sub-stellar companions (Feng+, 2022)
J/AJ/163/223 : Radial velocity study of π Mensae (Hatzes+, 2022)
J/AJ/163/218 : Radial velocity of Gliese 411 with APF and HIRES (Hurt+, 2022)
J/A+A/657/A7 : Stellar & substellar companions from Gaia EDR3 (Kervella+, 2022)
J/AJ/165/176 : Doppler constraints comp. to Sun-like stars (Laliotis+, 2023)
J/A+A/672/A93 : AF Lep b spectrum (Mesa+, 2023)
J/AJ/165/151 : List of Exoplanet Radial Velocity "green prime" (Newman+, 2023)
J/ApJS/272/30 : Habitable Worlds Observatory (HWO): 164 targets (Harada+, 2024)
J/AJ/167/139 : HPIC catalog & potential contaminants from Gaia (Tuchow+, 2024)
Byte-by-byte Description of file: targets.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- HIP Hipparcos (I/311) identifier
11 A1 --- Acc? Star with astrometric acceleration? (1)
13- 16 A4 --- Plot Interactive plot of companion mass vs separation
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Note (1): Flag as follows:
Y = Star with astrometric acceleration (Table 4); 54 occurrences
N = Star without astrometric acceleration (Table 5); 102 occurrences
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP Hipparcos (I/311) identifier
11- 19 F9.4 arcsec Sep [0.01/1000] Angular separation (rho)
21- 25 F5.3 Msun M2-3sig [0/1.5] Companion mass at -3σ
27- 31 F5.3 Msun M2-2sig [0/1.5] Companion mass at -2σ
33- 37 F5.3 Msun M2-1sig [0/1.5] Companion mass at -1σ
39- 43 F5.3 Msun M2 [0/1.5] Mean companion mass (mu)
45- 49 F5.3 Msun M2+1sig [0/1.5] Companion mass at +1σ
51- 55 F5.3 Msun M2+2sig [0/1.5] Companion mass at +2σ
57- 61 F5.3 Msun M2+3sig [0/1.5] Companion mass at +3σ
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- HIP Hipparcos (I/311) identifier
11- 19 F9.4 arcsec Sep [0.01/1000] Angular separation (rho)
21- 25 F5.3 Msun M2-1sig [0/1.44] Companion mass at 1σ
27- 31 F5.3 Msun M2-2sig [0/1.44] Companion mass at 2σ
33- 37 F5.3 Msun M2-3sig [0/1.44] Companion mass at 3σ
39- 43 F5.3 Msun M2-4sig [0.003/1.44] Companion mass at 4σ
45- 49 F5.3 Msun M2-5sig [0.032/1.44] Companion mass at 5σ
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Robin Leichtnam [CDS] 29-Jun-2026