HD 109271

Last updated
HD 109271
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Virgo [1]
Right ascension 12h 33m 35.555s [2]
Declination −11° 37′ 18.73″ [2]
Apparent magnitude  (V)8.05 ± 0.01 [3]
Characteristics
Spectral type G5 V [3] + DA [4]
B−V color index +0.658±0.002 [3]
Astrometry
Radial velocity (Rv)−4.971±0.0011 [5] km/s
Proper motion (μ)RA: −169.971 mas/yr [2]
Dec.: 81.000 mas/yr [2]
Parallax (π)17.9082±0.0379  mas [2]
Distance 182.1 ± 0.4  ly
(55.8 ± 0.1  pc)
Absolute magnitude  (MV)4.1±0.1 [3]
Position (relative to HD 109271 A) [4]
ComponentHD 109271 B
Epoch of observation 2018
Angular distance 5.425″
Position angle 267.354°
Projected separation 304 AU
Details [3]
HD 109271 A
Mass 1.047±0.024  M☉
Radius 1.295+0.023
−0.020 [6]   R☉
Luminosity 1.649±0.008 [6]   L☉
Surface gravity (log g)4.28±0.10  cgs
Temperature 5,783±62  K
Metallicity [Fe/H]0.10±0.05  dex
Rotational velocity (v sin i)2.7 km/s
Age 7.3±1.2  Gyr
HD 109271 B
Mass ~0.6 [4]   M☉
Other designations
BD−10°3494, HD 109271, HIP 61300, SAO 157362, LTT 4770 [7]
Database references
SIMBAD data
Exoplanet Archive data

HD 109271 is a wide binary star system in the constellation of Virgo. The brighter member of the binary has a pair of orbiting exoplanets. With an apparent visual magnitude of 8.05, [3] it cannot be seen with the naked eye. Parallax measurements made by Gaia put the star at a distance of 181 light-years (55 parsecs) away from the Sun, but it is drifting closer with a radial velocity of −5 km/s. [5] The system shows a high proper motion, traversing the celestial sphere at an angular rate of 0.232 arcsec yr−1. [8]

The primary component is an ordinary G-type main-sequence star with a stellar classification of G5 V. It is a much older star than the Sun with an age of about 7.3 billion years, and is spinning with a projected rotational velocity of 2.7 km/s. [3] This star has 7% more mass than the Sun and a 30% greater girth. [6] The abundance of iron, a measure of the star's metallicity, is similar but slightly higher than in the Sun. [3] It is radiating 1.65 [6] times the luminosity of the Sun from its photosphere at an effective temperature of around 5,783 K. [3]

In 2020, a white dwarf companion of 0.6 M☉ was found orbiting the primary at an angular separation of 5.4″ along a position angle of 267°. At the distance of this system, this corresponds to a projected separation of 304  AU . That is, they are physically separated by at least this distance. Additional stellar companions are ruled out down to a separation of 0.15″ from the primary. [4]

Planetary system

From 2003 to 2012, the star was under observance from the High Accuracy Radial Velocity Planet Searcher (HARPS). [3] In 2012, two eccentric hot Neptune-mass planets were deduced by radial velocity. They were published in January 2013. These are close to a 1:4 resonance, so the system is similar to HD 69830. A third Neptune in the Venus zone was hypothesised from the data. These planets managed to survive the post main-sequence epoch of the companion star, when it shed much of its original mass. [4]

The HD 109271 planetary system [9] [3]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b >0.054 ± 0.004  MJ 0.079 ± 0.0017.8543 ± 0.00090.25 ± 0.08——
c >0.076 ± 0.007  MJ 0.196 ± 0.00330.93 ± 0.020.15 ± 0.09——
d (unconfirmed)>0.07 MJ 14300.36——

References

  1. ↑ 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.
  2. 1 2 3 4 5 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. 1 2 3 4 5 6 7 8 9 10 11 Lo Curto, G.; et al. (2013). "The HARPS search for southern extrasolar planets: XXXVI. New multi-planet systems in the HARPS volume limited sample: a super-Earth and a Neptune in the habitable zone". Astronomy & Astrophysics. 551: 7. arXiv: 1301.2741 . Bibcode:2013A&A...551A..59L. doi:10.1051/0004-6361/201220415. S2CID   116916728. A59.
  4. 1 2 3 4 5 Ginski, Christian; et al. (2021). "How many suns are in the sky? A SPHERE multiplicity survey of exoplanet host stars". Astronomy & Astrophysics. 649: A156. arXiv: 2009.10363 . Bibcode:2021A&A...649A.156G. doi:10.1051/0004-6361/202038964. S2CID   221836281.
  5. 1 2 Soubiran, C.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv: 1804.09370 . Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795. S2CID   52952408.
  6. 1 2 3 4 Johns, Daniel; et al. (November 2018). "Revised Exoplanet Radii and Habitability Using Gaia Data Release 2". The Astrophysical Journal Supplement Series. 239 (1): 14. arXiv: 1808.04533 . Bibcode:2018ApJS..239...14J. doi: 10.3847/1538-4365/aae5fb . 14.
  7. ↑ "HD 109271". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2024-01-09.
  8. ↑ Luyten, W. J. (June 1995). "NLTT Catalogue (Luyten, 1979)". VizieR Online Data Catalog. Bibcode:1995yCat.1098....0L.
  9. ↑ "Planet HD 109271 b". Extrasolar Planets Encyclopaedia . Retrieved 3 September 2017.
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