HD 210702

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HD 210702
Observation data
Epoch J2000      Equinox J2000
Constellation Pegasus
Right ascension 22h 11m 51.3309s[1]
Declination +16° 02′ 25.9959″[1]
Apparent magnitude (V) 5.939
Characteristics
Spectral type K1IV
U−B color index 0.73
B−V color index 0.951[2]
R−I color index 0.49
Astrometry
Radial velocity (Rv)10.9 ± 2 km/s
Proper motion (μ) RA: −3.241±0.156[1] mas/yr
Dec.: −17.156±0.160[1] mas/yr
Parallax (π)18.4231 ± 0.0783[1] mas
Distance177.0 ± 0.8 ly
(54.3 ± 0.2 pc)
Absolute magnitude (MV)2.201
Details
Mass1.68 (1.50–1.84)[2] M☉
Radius5.2314±0.1171[3] R☉
Luminosity12.838±0.5569[3] L☉
Surface gravity (log g)3.19 ± 0.08[2] cgs
Temperature4780±18[3] K
Metallicity [Fe/H]0.03 [3] dex
Age5.0[3] Gyr
Other designations
BD+15º4592, HIP 109577, HR 8461, SAO 107729[4]
Database references
SIMBADdata

HD 210702 is an orange subgiant star located approximately 177 light-years away in the constellation of Pegasus. With a mass of 1.8 times that of the Sun, the star spent its main-sequence life as an A-type star. The visual luminosity is 11.38 times that of the Sun and the magnitude is near the naked-eye limit, but binoculars can easily see it.

Planetary system[]

The star shows variability in its radial velocity consistent with a planet-mass companion in a Keplerian orbit,[5] and one was duly discovered in April 2007, from observations at Lick and Keck Observatories in Mount Hamilton (California) and Mauna Kea (Hawai'i), United States.

The HD 210702 planetary system[6]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥1.808±0.097 MJ 1.148±0.057 354.10±0.70 0.028±0.034 — —

See also[]

References[]

  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c Sato, Bun'ei; et al. (2012). "Substellar Companions to Seven Evolved Intermediate-Mass Stars". Publications of the Astronomical Society of Japan. 64 (6). 135. arXiv:1207.3141. Bibcode:2012PASJ...64..135S. doi:10.1093/pasj/64.6.135.
  3. ^ a b c d e von Braun, Kaspar; et al. (2014). "Stellar diameters and temperatures – V. 11 newly characterized exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 438 (3): 2413–2425. arXiv:1312.1792. Bibcode:2014MNRAS.438.2413V. doi:10.1093/mnras/stt2360.
  4. ^ "HD 210702". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-15.
  5. ^ Johnson, John Asher; et al. (2007). "Retired A Stars and Their Companions: Exoplanets Orbiting Three Intermediate-Mass Subgiants". The Astrophysical Journal. 665 (1): 785–793. arXiv:0704.2455. Bibcode:2007ApJ...665..785J. doi:10.1086/519677.
  6. ^ Luhn, Jacob K.; et al. (2019). "Retired A Stars and Their Companions. VIII. 15 New Planetary Signals around Subgiants and Transit Parameters for California Planet Search Planets with Subgiant Hosts". The Astronomical Journal. 157 (4). 149. arXiv:1811.03043. Bibcode:2019AJ....157..149L. doi:10.3847/1538-3881/aaf5d0. S2CID 102486961.

Coordinates: Sky map 22h 11m 51.3311s, +16° 02′ 25.983″

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