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Rho Andromedae

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Rho Andromedae
Diagram showing star positions and boundaries of the Andromeda constellation and its surroundings
Location of ρ Andromedae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Andromeda
Right ascension 00h 21m 07.26896s[1]
Declination +37° 58′ 06.9727″[1]
Apparent magnitude (V) +5.19[2]
Characteristics
Spectral type F5IV-V[3]
U−B color index +0.039[2]
B−V color index +0.424[2]
Astrometry
Radial velocity (Rv)+10.4±0.6[4] km/s
Proper motion (μ) RA: +57.599[1] mas/yr
Dec.: –38.378[1] mas/yr
Parallax (π)20.1874 ± 0.1179 mas[1]
Distance161.6 ± 0.9 ly
(49.5 ± 0.3 pc)
Absolute magnitude (MV)+1.73[5]
Details
Radius3.37+0.07
−0.03[1] R☉
Luminosity17.93±0.13[1] L☉
Surface gravity (log g)3.84[6] cgs
Temperature6,471+25
−66[1] K
Metallicity [Fe/H]–0.09[6] dex
Rotational velocity (v sin i)44[6] km/s
Age1.3[5] Gyr
Other designations
ρ And, 27 Andromedae, BD+37 45, FK5 1009, HD 1671, HIP 1686, HR 82, SAO 53828, PPM 65222[7]
Database references
SIMBADdata

Rho Andromedae, Latinized from ρ Andromedae, is the Bayer designation for a star in the northern constellation of Andromeda. It has an apparent visual magnitude of +5.19,[2] which, according to the Bortle Dark-Sky Scale, is bright enough to be seen with the naked eye from dark suburban skies. Based upon parallax measurements, this star is at a distance of approximately 162 light-years (50 parsecs) from the Sun.[1] It is drifting further away with a radial velocity of +10 km/s.[4]

The stellar classification of this star is F5IV-V,[3] showing mixed spectral features of a main sequence and subgiant stage. It is about 1.3[5] billion years old with 3.4[1] times the girth of the Sun and is spinning with a projected rotational velocity of 44 km/s.[6] The outer envelope is radiating around 18 times the luminosity of the Sun from its photosphere at an effective temperature of 6,471 K,[1] giving it the yellow-white hue of an F-type star.[8] X-ray emissions were detected from this star during the EXOSAT mission.[9]

Naming

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In Chinese, 天廄 (Tiān Jiù), meaning Celestial Stable, refers to an asterism consisting of ρ Andromedae, θ Andromedae, σ Andromedae and seven fainter, unidentified stars. Consequently, the Chinese name for ρ Andromedae itself is 天廄二 (Tiān Jiù èr, English: the Second Star of Celestial Stable.)[10]

References

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  1. ^ a b c d e f g h i j k 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 d Breger, M. (March 1968), "UBV and narrow-band UVBY photometry of bright stars", Astronomical Journal, 73: 84–85, Bibcode:1968AJ.....73...84B, doi:10.1086/110602.
  3. ^ a b Gray, R. O.; et al. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148–2158, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
  4. ^ a b Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  5. ^ a b c Nordström, B.; et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics, 418: 989–1019, arXiv:astro-ph/0405198, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959, S2CID 11027621.
  6. ^ a b c d Balachandran, Suchitra (May 1, 1990). "Lithium depletion and rotation in main-sequence stars". Astrophysical Journal, Part 1. 354: 310–332. Bibcode:1990ApJ...354..310B. doi:10.1086/168691.
  7. ^ "* rho And -- Star". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-06-24.
  8. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16.
  9. ^ Gondoin, P.; Mangeney, A.; Praderie, F. (March 1987), "Solar-type giants - New X-ray detections from EXOSAT observations", Astronomy and Astrophysics, 174 (1–2): 187–196, Bibcode:1987A&A...174..187G.
  10. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 18 日
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