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ε Trianguli
Location of ε Trianguli (circled)
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Triangulum
Right ascension 02h 02m 57.95579s [1]
Declination +33° 17′ 02.8813″ [1]
Apparent magnitude (V) +5.50 [2]
Characteristics
Spectral type A2 V [3]
U−B color index +0.06 [2]
B−V color index +0.03 [2]
Astrometry
Radial velocity (Rv)3.3 [4] km/s
Proper motion (μ) RA: –15.97 [1]  mas/ yr
Dec.: –7.22 [1]  mas/ yr
Parallax (π)8.33 ± 0.34  mas [1]
Distance390 ± 20  ly
(120 ± 5  pc)
Absolute magnitude (MV)+0.11 [5]
Details
Mass2.75±0.05 [6]  M☉
Radius3.28 [7]  R☉
Luminosity93 [6]  L☉
Surface gravity (log g)3.76 [8]  cgs
Temperature10,000 [7]  K
Rotational velocity (v sin i)107 [9] km/s
Age600 [7]  Myr
Other designations
ε Tri, 3 Tri, BD+32° 369, HD 12471, HIP 9570, HR 599, SAO 55218 [10]
Database references
SIMBAD data

Epsilon Trianguli, Latinized from ε Trianguli, is a binary star [11] system in the northern constellation of Triangulum. Based upon measurement of its trigonometric parallax, it is approximately 390 light years from Earth. [1]

The primary component is an A-type main sequence star with a stellar classification of A2 V, [3] an apparent magnitude of +5.50 and an estimated age of 600 million years. [7] It has 2.75 [6] times the mass of the Sun and is spinning with a projected rotational velocity of 107 km/s. [9] The radius of this star is more than three times the radius of the Sun, and the photosphere has an effective temperature of about 10,000. [7] The secondary component has an apparent magnitude of 11.4 and is separated from the primary by an angle of 3.9  arcseconds. [12]

An excess emission of infrared radiation suggests the presence of a dusty disk in orbit about the primary. This disk has a mean radius of 105  AU, or 105 times the separation of the Earth from the Sun, and is radiating at a temperature of 85 K. [7]

This star system is a probable member of the Ursa Major Moving Group of stars that share a common motion through space. [8] The space velocity components of Epsilon Trianguli are U, V, W = [+11.8, +11.4, –3.8] km/s. [13]

References

  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. arXiv: 0708.1752. Bibcode: 2007A&A...474..653V. doi: 10.1051/0004-6361:20078357. S2CID  18759600.
  2. ^ a b c 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 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
  4. ^ Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode: 1953GCRV..C......0W
  5. ^ 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.
  6. ^ a b c Zorec, J.; Royer, F. (January 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.
  7. ^ a b c d e f Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv: astro-ph/0609555, Bibcode: 2007ApJ...660.1556R, doi: 10.1086/509912, S2CID  11879505
  8. ^ a b Monier, R. (November 2005), "Abundances of a sample of A and F-type dwarf members of the Ursa Major Group", Astronomy and Astrophysics, 442 (2): 563–566, Bibcode: 2005A&A...442..563M, doi: 10.1051/0004-6361:20053222
  9. ^ a b Royer, F.; Zorec, J.; Gómez, A. E. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv: astro-ph/0610785, Bibcode: 2007A&A...463..671R, doi: 10.1051/0004-6361:20065224, S2CID  18475298
  10. ^ "eps Tri -- Variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-13
  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. ^ 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
  13. ^ King, Jeremy R.; et al. (April 2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980–2017, Bibcode: 2003AJ....125.1980K, doi: 10.1086/368241
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