Tau1 Arietis

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Tau1 Arietis
Diagram showing star positions and boundaries of the Aries constellation and its surroundings
Cercle rouge 100%.svg

Location of τ1 Arietis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 03h 21m 13.62411s[1]
Declination +21° 08′ 49.5150″[1]
Apparent magnitude (V) 5.27[2]
Spectral type B5 IV[3]
U−B color index –0.53[2]
B−V color index –0.06[2]
Radial velocity (Rv) +14[4] km/s
Proper motion (μ) RA: +20.98[1] mas/yr
Dec.: –21.80[1] mas/yr
Parallax (π) 6.41 ± 0.73[1] mas
Distance approx. 510 ly
(approx. 160 pc)
Absolute magnitude (MV) −0.66[5]
Mass 5.0 ± 0.1[6] M
Radius 3.4–3.6[7] R
Luminosity 234[5] L
Rotational velocity (v sin i) 30[8] km/s
Age 54.8 ± 5.4[6] Myr
Other designations
τ1 Ari, 61 Arietis, BD+20 543, FK5 1094, HD 20756, HIP 15627, HR 1005, SAO 75886.[9]
Database references

Tau1 Arietis, Latinized from τ1 Arietis, is the Bayer designation for a triple star system[10] in the northern constellation of Aries. Based upon an annual parallax shift of 6.41 mas,[1] it is approximately 510 light-years (160 parsecs) distant from Earth. The combined apparent visual magnitude is 5.27,[2] making it faintly visible to the naked eye.

The inner pair form an eclipsing binary system, with the brightness of the pair decreasing by 0.06 in magnitude during an eclipse of the primary.[11] The third component is located at an angular separation of 0.810 arcseconds and has a magnitude of 8.17.[10] The primary component is a subgiant star with a stellar classification of B5 IV.[3] It has around 3.5[7] times the size of the Sun with five[6] times the Sun's radius.

This system is a member of the Cas-Tau OB association of stars that share a common motion through space.[12]


  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Crawford, D. L.; Barnes, J. V.; Golson, J. C. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220. 
  3. ^ a b Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179. 
  4. ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E. 
  5. ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, Bibcode:2012AstL...38..331A, arXiv:1108.4971Freely accessible, doi:10.1134/S1063773712050015. 
  6. ^ a b c Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, Bibcode:2011MNRAS.410..190T, arXiv:1007.4883Freely accessible, doi:10.1111/j.1365-2966.2010.17434.x. 
  7. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367: 521–524, Bibcode:2001A&A...367..521P, arXiv:astro-ph/0012289Freely accessible, doi:10.1051/0004-6361:20000451. 
  8. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590. 
  9. ^ "tau01 Ari -- Eclipsing binary of beta Lyr type (semi-detached)", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-08-11. 
  10. ^ 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, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x. 
  11. ^ Malkov, O. Yu.; et al. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics, 446 (2): 785–789, Bibcode:2006A&A...446..785M, doi:10.1051/0004-6361:20053137. 
  12. ^ de Zeeuw, P. T.; et al. (January 1999), "A HIPPARCOS Census of the Nearby OB Associations", The Astronomical Journal, 117 (1): 354–399, Bibcode:1999AJ....117..354D, arXiv:astro-ph/9809227Freely accessible, doi:10.1086/300682. 

External links[edit]