Misplaced Pages

Theta Andromedae

Location of θ Andromedae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Andromeda
Right ascension	00 17 05.50236
Declination	+38° 40′ 53.8886″
Apparent magnitude (V)	4.61
Characteristics
Evolutionary stage	main sequence
Spectral type	A2 V
U−B color index	+0.05
B−V color index	+0.06
Variable type	Constant
Astrometry
Radial velocity (Rv)	0.9 km/s
Proper motion (μ)	RA: −57.551(307) mas/yr Dec.: −14.795(155) mas/yr
Parallax (π)	18.8747 ± 0.4251 mas
Distance	173 ± 4 ly (53 ± 1 pc)
Absolute magnitude (MV)	−0.25
Orbit
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
Mass	2.83±0.08 M☉
Luminosity	113 L☉
Surface gravity (log g)	3.95 cgs
Temperature	8,960 K
Metallicity	+0.14 dex
Rotational velocity (v sin i)	102 km/s
Other designations
θ And, 24 Andromedae, BD+37°34, HD 1280, HIP 1366, HR 63, SAO 53777, PPM 65154
Database references
SIMBAD	data

Theta Andromedae is a binary star 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, and has an apparent visual magnitude of 4.6. 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.

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

A stellar companion was detected in 1986 and reported in 1989. This fainter companion is separated from Theta Andromedae by 0.06 arcseconds. 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.

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.)

References

1. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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. ^ 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

External links

• Image Theta Andromedae

v t e Constellation of Andromeda
Adhil Andromeda in Chinese astronomy List of Andromeda's satellite galaxies List of stars in Andromeda
Stars	Bayer α (Alpheratz) β (Mirach) γ (Almach) δ ε ζ η θ ι κ λ μ ν ξ (Adhil) ο π ρ σ τ υ (Titawin) φ χ ψ ω A b c υ Per (Nembus) Flamsteed 2 3 4 5 6 7 8 9 10 11 12 13 14 (Veritate) 15 18 22 23 26 28 32 36 39 41 44 45 47 55 56 58 59 63 64 65 66 6 Per Variable R T U W Z RT RV RX SU SW TU TW WZ XZ AB AC AD AE AF AR BM BX CC CG CN DS DX EG ET EU FF GO GP GQ GX GR GY HH HN IW KK KX KZ LL LN LP LQ OP OS OU PX PY QR QV QX V385 V428 V439 V455 V529 V807 HR 1 40 56 78 104 122 134 178 275 282 283 289 379 410 483 687 746 748 8884 8925 8950 8962 8973 9011 9074 9075 9105 HD 16175 (Buna) 222155 Other 3XMM J004232.1+411314 ADS 48 HAT-P-6 (Sterrennacht) HAT-P-16 HAT-P-19 HAT-P-28 M31-RV KELT-1 NGC 44 NGC 82 NGC 84 NGC 91 NGC 162 NGC 464 Qatar-3 Qatar-4 Qatar-5 PA-99-N2 WASP-1 WISE 0146+4234 WISE J0005+3737 WISE J004945.61+215120.0
Exoplanets 14 Andromedae b κ Andromedae b υ Andromedae b c d Gliese 15 Ab c HD 13931 b HD 16175 b HAT-P-6b HAT-P-32b WASP-1b WASP-33b Qatar-4b Qatar-5b
Star clusters	NGC 206 272 752 956 7686 Other Mayall II RBC EXT8
Nebulae	NGC 7662
Galaxies	Messier 32 110 NGC 5 11 13 19 20 21 27 39 43 48 49 51 67 68 69 70 71 72 74 76 79 80 81 83 85 86 90 93 94 96 97 108 109 112 140 149 160 169 181 183 184 214 218 226 228 229 233 243 252 258 260 262 280 304 317 389 393 404 425 431 477 512 513 523 528 529 531 536 542 561 605 620 668 679 687 700 703 704 705 708 709 710 712 714 717 721 732 753 759 801 812 834 891 906 910 911 912 913 920 937 980 995 996 999 1000 7640 7836 Numbered I II III IV V VIII IX X XI XVIII XIX XXI Other 3C 66A 3C 66B Andromeda Galaxy Arp 273 Donatiello I UGC 1840
Galaxy clusters Abell 262 NGC 68 group
Astronomical events GRB 101225A SN 1885A (S)
Category

• A-type main-sequence stars
• Am stars
• Spectroscopic binaries
• Binary stars
• Andromeda (constellation)
• Bayer objects
• Durchmusterung objects
• Flamsteed objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects