HD 191760
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Telescopium
Right ascension 20h 13m 26.74628s[1]
Declination −46° 12′ 03.7089″[1]
Apparent magnitude (V) 8.26[2]
Characteristics
Evolutionary stage Subgiant[3]
Spectral type G3IV/V[3]
B−V color index 0.668±0.014[2]
Variable type Constant[4]
Astrometry
Radial velocity (Rv)−30.06±0.20[1] km/s
Proper motion (μ) RA: −0.723 mas/yr[1]
Dec.: −62.019 mas/yr[1]
Parallax (π)11.2610 ± 0.1091 mas[1]
Distance290 ± 3 ly
(88.8 ± 0.9 pc)
Absolute magnitude (MV)3.71[2]
Orbit[3]
Period (P)505.65±0.42 d
Semi-major axis (a)1.35 AU
Eccentricity (e)0.63±0.01
Inclination (i)158.96±5.99[5]°
Periastron epoch (T)2454835.65±2.06
Argument of periastron (ω)
(secondary)		200.37±0.28°
Semi-amplitude (K1)
(primary)		1.04783±0.03871 km/s
Details[3]
Mass1.28+0.02
−0.10 M☉
Radius1.62±0.07 R☉
Luminosity2.69±0.20 L☉
Surface gravity (log g)4.13+0.05
−0.04 cgs
Temperature5,794±76 K
Metallicity [Fe/H]0.29±0.07 dex
Rotation25.2 or 35.1 d
Rotational velocity (v sin i)2.33±0.05 km/s
Age4.1+0.8
−2.8 Gyr
HD 191760 b
Mass106.34±29.03[5] MJup
Other designations
CD−46°13445, HD 191760, HIP 99661, SAO 230105[6]
Database references
SIMBADdata

HD 191760 is a star in the southern constellation of Telescopium. It has a yellow hue but is too dim to be visible to the naked eye with an apparent visual magnitude of 8.26.[2] The star is located at a distance of approximately 290 light-years from the Sun based on parallax, but is drifting closer with a radial velocity of −30 km/s.[1]

The stellar classification of G3IV/V is consistent with a star that is evolving onto the subgiant branch, having exhausted the supply of hydrogen at its core. It is roughly four billion years old with a modest projected rotational velocity of 2.3 km/s. The star is 28% more massive than the Sun and 62% as large. The metallicity, or abundance of heavier elements, is higher than in the Sun. The star is radiating 2.7 times the luminosity of the Sun from its photosphere at an effective temperature of 5,794 K.[3]

Companion

Using the ESO HARPS instrument, in 2009 HD 191760 was found to have a brown dwarf at least 38 times as massive as Jupiter orbiting at an average distance of 1.35 AU in a period of 506 days. This is an unusual distance from the star that has been termed the 'brown dwarf desert'.[3] The upper limit on the mass of this object is 28% of the mass of the Sun (0.28 M☉).[7]

In 2023, the true mass of this object was determined using Gaia astrometry. At about 106 times the mass of Jupiter, this is a low-mass star (presumably a red dwarf) and not a brown dwarf.[5]

References

  1. 1 2 3 4 5 6 7 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.
  2. 1 2 3 4 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. 1 2 3 4 5 6 Jenkins, J. S.; et al. (September 2009). "First Results From the Calan–Hertfordshire Extrasolar Planet Search: Exoplanets and the Discovery of an Eccentric Brown Dwarf in the Desert". Monthly Notices of the Royal Astronomical Society. 398 (2): 911–17. arXiv:0905.2985. Bibcode:2009MNRAS.398..911J. doi:10.1111/j.1365-2966.2009.15097.x. S2CID 1913088.
  4. ↑ Paunzen, E.; et al. (January 1995). "Detection of Variability in HD191850". Information Bulletin on Variable Stars. 4151: 1. Bibcode:1995IBVS.4151....1P.
  5. 1 2 3 Stevenson, Adam T.; Haswell, Carole A.; et al. (December 2023). "Combing the brown dwarf desert with Gaia DR3". Monthly Notices of the Royal Astronomical Society. 526 (4): 5155–5171. arXiv:2310.02695. Bibcode:2023MNRAS.526.5155S. doi:10.1093/mnras/stad3041.
  6. ↑ "HD 191760". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-12.
  7. ↑ Sahlmann, J.; et al. (January 2011). "Search for brown-dwarf companions of stars". Astronomy and Astrophysics. 525: 24. arXiv:1009.5991. Bibcode:2011A&A...525A..95S. doi:10.1051/0004-6361/201015427. S2CID 119276951. A95.
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