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Theta Andromedae

Today, Theta Andromedae is a topic that generates great interest and debate in society. Its relevance has been increasing in recent years, covering various areas such as technology, culture, politics and science. Theta Andromedae has managed to capture the attention of experts and fans, as well as citizens in general, becoming a fundamental part of the media and social agenda. In this article, we will explore in depth the different aspects and facets related to Theta Andromedae, with the aim of offering a comprehensive and updated vision on this topic of great importance today.

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Theta Andromedae
Location of θ Andromedae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 17m 05.50236s[1]
Declination +38° 40′ 53.8886″[1]
Apparent magnitude (V) 4.61[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A2 V[4]
U−B color index +0.05[2]
B−V color index +0.06[2]
Variable type Constant[5]
Astrometry
Radial velocity (Rv)0.9[6] km/s
Proper motion (μ) RA: −57.551(307)[1] mas/yr
Dec.: −14.795(155)[1] mas/yr
Parallax (π)18.8747±0.4251 mas[1]
Distance173 ± 4 ly
(53 ± 1 pc)
Absolute magnitude (MV)−0.25[7]
Orbit[8]
Period (P)1033+91
−77 days
Semi-major axis (a)25+32
−13 mas
Eccentricity (e)0.95+0.04
−0.40
Inclination (i)69+8
−22°
Longitude of the node (Ω)263+50
−156°
Periastron epoch (T)238+343
−143
Argument of periastron (ω)
(secondary)		89+175
−29°
Details
A
Mass2.83±0.08[3] M☉
Luminosity113[7] L☉
Surface gravity (log g)3.95[9] cgs
Temperature8,960[9] K
Metallicity +0.14[9] dex
Rotational velocity (v sin i)102[3] km/s
Other designations
θ And, 24 Andromedae, BD+37°34, HD 1280, HIP 1366, HR 63, SAO 53777, PPM 65154[10]
Database references
SIMBADdata

Theta Andromedae is a binary star[11] system in the northern constellation of Andromeda. Theta Andromedae, Latinized from θ Andromedae, is its Bayer designation. It is located at a distance of approximately 173 light-years (53 parsecs) from the Sun,[1] and has an apparent visual magnitude of 4.6.[2] On the Bortle Dark-Sky Scale, this makes it visible to the naked eye from outside urban regions. Based on its motion through space, this system appears to be a member of the Sirius supercluster.[12]

The brighter component is a white hued A-type main-sequence star with a stellar classification of A2 V.[4] It is one of the least photometrically variable stars known.[5] The star shows a high rate of rotation with a projected rotational velocity of 102 km/s.[3] It has an estimated 2.8[3] times the mass of the Sun and is radiating 113[7] times the Sun's luminosity from its photosphere at an effective temperature of 8,960 K.[9] The relatively high chemical abundances of iron and heavier elements suggests it may be a fast rotating Am star.[5]

A stellar companion was detected in 1986 and reported in 1989.[13] This fainter companion is separated from Theta Andromedae by 0.06 arcseconds.[11] The secondary appears to be a massive, possibly A-type, star orbiting at a distance of around one astronomical unit with a period of 2.83 years and a large orbital eccentricity (ovalness) of 0.95.[8]

Naming

In Chinese, 天廄 (Tiān Jiù), meaning Celestial Stable, refers to an asterism consisting of θ Andromedae, ρ Andromedae and σ Andromedae. Consequently, the Chinese name for θ Andromedae itself is known as 天廄一 (Tiān Jiù yī, English: the First Star of Celestial Stable.)[14]

References

  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
  3. ^ a b c d e Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  4. ^ a b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  5. ^ a b c Koçer, D.; et al. (2003), "Elemental abundance analyses with DAO spectrograms-XXVII. The superficially normal stars θ And (A2 IV), ϵ Del (B6 III), ϵ Aqr (A1. 5 V), and ι And (B9 V)", Astronomy & Astrophysics, 406 (3): 975–980, Bibcode:2003A&A...406..975K, doi:10.1051/0004-6361:20030620.
  6. ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
  7. ^ a b c 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.
  8. ^ a b Goldin, A.; Makarov, V. V. (September 2006), "Unconstrained Astrometric Orbits for Hipparcos Stars with Stochastic Solutions", The Astrophysical Journal Supplement Series, 166 (1): 341–350, arXiv:astro-ph/0606293, Bibcode:2006ApJS..166..341G, doi:10.1086/505939, S2CID 15673734.
  9. ^ a b c d Hill, G. M. (February 1995), "Compositional differences among the A-type stars. 2: Spectrum synthesis up to V sin i = 110 km/s", Astronomy and Astrophysics, 294 (2): 536–546, Bibcode:1995A&A...294..536H.
  10. ^ "tet And", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2021-05-31.
  11. ^ a b Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  12. ^ Palous, J.; Hauck, B. (July 1986), "The Sirius supercluster", Astronomy and Astrophysics, 162: 54–61, Bibcode:1986A&A...162...54P.
  13. ^ McAlister, Harold A.; et al. (February 1989), "ICCD Speckle Observations of Binary Stars. IV. Measurements During 1986-1988 from the Kitt Peak 4-m Telescope", Astronomical Journal, 97: 510, Bibcode:1989AJ.....97..510M, doi:10.1086/115001.
  14. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 18 日 Archived 2011-05-21 at the Wayback Machine
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