HD 16760

HD 16760

Observation data Epoch J2000.0       Equinox J2000.0
Constellation	Perseus [1]
Right ascension	02h 42m 21.31345s [2]
Declination	+38° 37′ 07.2319″ [2]
Apparent magnitude  (V)	8.76 [3]
Characteristics
Evolutionary stage	main sequence [4]
Spectral type	G5V [4]
B−V color index	0.715 [4]
Astrometry
Radial velocity (Rv)	−3.95±0.38 [2] km/s
Proper motion (μ)	RA: +73.809 mas/yr [2] Dec.: −106.607 mas/yr [2]
Parallax (π)	17.5714±0.5942  mas [2]
Distance	186 ± 6  ly (57 ± 2  pc)
Absolute magnitude  (MV)	5.41 [4]
Orbit [5]
Companion	HD 16760 b
Period (P)	466.048±0.057  d
Semi-major axis (a)	1.161±0.097  AU
Eccentricity (e)	0.0812±0.0018
Inclination (i)	2.6°±0.5° [6] or 43.3+32.2 −28.8 [7] °
Periastron epoch (T)	24513802.6±1.9
Argument of periastron (ω) (secondary)	241.9±1.4°
Semi-amplitude (K1) (primary)	407.16±0.71 km/s
Details
HD 16760 A
Mass	0.78 ± 0.05 [4]   M☉
Radius	0.81 ± 0.27 [4]   R☉
Luminosity (bolometric)	0.72 ± 0.43 [4]   L☉
Surface gravity (log g)	4.47 ± 0.06 [4]   cgs
Temperature	5629 ± 44 [4]   K
Metallicity [Fe/H]	+0.067 ± 0.05 [4]   dex
Rotational velocity (v sin i)	0.5 ± 0.5 [4]  km/s
Age	1.3 ± 0.9 [8]   Gyr
HD 16760 b
Mass	0.267±0.014 [9] [a]   M☉
Mass	21.5+5.0 −4.5 [7] [a]   MJup
HD 16760 B
Mass	0.756 [9]   M☉
Other designations
BD+37°604, HD 16760, WDS J02424+3837
A: HIP 12638, SAO 55798, TYC 2845-2243-1, GSC 02845-02243, 2MASS J02422130+3837073 [10]
B: HIP 12635, TYC 2845-2242-1, GSC 02845-02242, 2MASS J02422094+3837212 [11]
Database references
SIMBAD	A
	Ab
	B

HD 16760 is a binary star system approximately 186 light-years away in the constellation Perseus. The primary star HD 16760A (HIP 12638) is a G-type main sequence star similar to the Sun. The secondary, HD 16760B (HIP 12635) is 1.521 magnitudes fainter and located at a separation of 14.6 arcseconds from the primary, corresponding to a physical separation of at least 660 AU.

The primary star also has a companion, either a red dwarf ^[6] or a brown dwarf, that is designated HD 16760 b (lowercase). ^[7] SIMBAD also lists the designation HD 16760C for this object. ^[12]

Companion (HD 16760 b)

				HD 16760A
				Period = 466 d
				HD 16760b
		14.6″ separation
		HD 16760B

Hierarchy of orbits in the HD 16760 system

The companion object was discovered independently by the SOPHIE extrasolar planets program ^[13] and the N2K Consortium. ^[4] It has a minimum mass slightly exceeding the lower limit required for fusion of deuterium in its interior. This criterion is sometimes used to distinguish between brown dwarfs, which lie above the limit, and planets which lie below the limit. ^[14] However its orbit is nearly circular, indicating that it may have formed in the same way as planets do, from a circumstellar disc. ^[13] The formation of massive planets up to 20–25 Jupiter masses has been predicted in some models of the core accretion process. ^[15] The identity of this object as a brown dwarf or a massive planet was thus unclear.

However, data analysed from direct imaging of the companion object using ground-based telescopes fitted with adaptive optics has revealed that it is aligned in a much more face-on orbit than previously realised. Consequently, its mass has been revised upwards. With a mass calculated at around one quarter that of the Sun, or nearly 300 Jupiter masses, it easily qualifies as a stellar object, probably a red dwarf. ^[6] A 2020 study using Gaia astrometry supported a stellar true mass, ^[16] but a 2026 study instead found a mass consistent with a brown dwarf. ^[7] These two studies do not incorporate data from direct imaging.

The same 2026 study found evidence for a second companion from radial velocity. This candidate object would have a 234-day period and a minimum mass of 0.4 Jupiter masses, making it a probable planet. ^[7]

Notes

1. Two discrepant masses from different sources are listed.

References

1. Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR .
2. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR .
3. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355. Bibcode:2000A&A...355L..27H.
4. Bunei Sato; Debra A. Fischer; Shigeru Ida; Hiroki Harakawa; Masashi Omiya; John A. Johnson; Geoffrey W. Marcy; Eri Toyota; Yasunori Hori; Howard Isaacson; Andrew W. Howard; Kathryn M.G. Peek (2009). "A Substellar Companion in a 1.3 yr Nearly-circular Orbit of HD 16760". The Astrophysical Journal. 703 (1): 671–674. arXiv: 0907.5080 . Bibcode:2009ApJ...703..671S. doi:10.1088/0004-637X/703/1/671. S2CID   5435270.
5. Ment, Kristo; et al. (2018). "Radial Velocities from the N2K Project: Six New Cold Gas Giant Planets Orbiting HD 55696, HD 98736, HD 148164, HD 203473, and HD 211810". The Astronomical Journal. 156 (5). 213. arXiv: 1809.01228 . Bibcode:2018AJ....156..213M. doi: 10.3847/1538-3881/aae1f5 . S2CID   119243619.
6. Evans T.M.; Ireland M.J.; Kraus A.L.; Martinache F.; Stewart P.; Tuthill P.G.; Lacour S.; Carpenter, J.M.; Hillenbrand L.A. (2011). "Mapping The Shores Of The Brown Dwarf Desert III: Young Moving Groups". The Astrophysical Journal. 744 (2): 120. arXiv: 1109.5900 . Bibcode:2012ApJ...744..120E. doi:10.1088/0004-637X/744/2/120. S2CID   118650120.
7. Piccinini, G.; Petralia, A.; et al. (January 2026). "True Masses using RV data with Hipparcos and Gaia Astrometry". Astronomy & Astrophysics . arXiv: 2601.09401 .
8. Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv: 1411.4302 . Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID   54555839.
9. Gratton, R.; Bonavita, M.; Mesa, D.; Desidera, S.; Zurlo, A.; Marino, S.; D’Orazi, V.; Rigliaco, E.; Nascimbeni, V.; Barbato, D.; Columba, G.; Squicciarini, V. (2024-05-01). "Stellar companions and Jupiter-like planets in young associations". Astronomy & Astrophysics. 685: A119. arXiv: 2402.02148v1 . Bibcode:2024A&A...685A.119G. doi:10.1051/0004-6361/202348393. ISSN   0004-6361.
10. "HD 16760". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 15 January 2025.
11. "HD 16760B". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 15 January 2025.
12. "HD 16760C". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 15 January 2025.
13. Bouchy, François; Hébrard, Guillaume; Udry, Stéphane; Delfosse, Xavier; Boisse, Isabelle; Desort, Morgan; Bonfils, Xavier; Eggenberger, Anne; Ehrenreich, David; Forveille, Thierry; Le Coroller, Hervé; Lagrange, Anne-Marie; Lovis, Christophe; Moutou, Claire; Pepe, Francesco; Perrier, Christian; Pont, Frédéric; Queloz, Didier; Santos, Nuno C.; Ségransan, Damien; Vidal-Madjar, Alfred (2009). "The SOPHIE northern extrasolar planets. I. A companion close to the planet/brown-dwarf transition around HD16760". Astronomy and Astrophysics. 505 (2): 853–858. Bibcode:2009A&A...505..853B. doi: 10.1051/0004-6361/200912427 .
14. "Definition of a "Planet"". Working Group on Extrasolar Planets (WGESP) of the International Astronomical Union.
15. Christoph Mordasini; Yann Alibert; Willy Benz; Dominique Naef (2007). "Giant Planet Formation by Core Accretion". arXiv: 0710.5667 [astro-ph].
16. Kiefer, Flavien; Hébrard, Guillaume; Lecavelier, Alain; Martioli, Eder; Dalal, Shweta; Vidal-Madjar, Alfred (2021). "Determining the true mass of radial-velocity exoplanets with Gaia 9 planet candidates in the brown-dwarf/stellar regime and 27 confirmed planets". Astronomy & Astrophysics. A7: 645. arXiv: 2009.14164 . Bibcode:2021A&A...645A...7K. doi:10.1051/0004-6361/202039168. S2CID   221995447.