Epsilon Trianguli
 Location of ε Trianguli (circled) |
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| Observation data Epoch J2000.0 Equinox J2000.0 |
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|---|---|
| Constellation | Triangulum |
| Right ascension | 02h 02m 57.95579s[1] |
| Declination | +33° 17′ 02.8813″[1] |
| Apparent magnitude (V) | +5.50[2] |
| Characteristics | |
| Spectral type | A2V |
| U−B color index | +0.06[2] |
| B−V color index | +0.03[2] |
| Astrometry | |
| Radial velocity (Rv) | 3.3[3] km/s |
| Proper motion (μ) | RA: –15.97[1] mas/yr Dec.: –7.22[1] mas/yr |
| Parallax (π) | 8.33 ± 0.34[1] mas |
| Distance | 390 ± 20 ly (120 ± 5 pc) |
| Details | |
| Radius | 3.28[4] R☉ |
| Surface gravity (log g) | 3.76[5] |
| Temperature | 10,000[4] K |
| Rotational velocity (v sin i) | 107[6] km/s |
| Age | 6.0 × 108[4] years |
| Other designations | |
Epsilon Trianguli (ε Tri / ε Trianguli) is a binary star in the constellation Triangulum. Based upon measurement of its trigonometric parallax, it is approximately 390 light years from Earth.[1]
The primary component is a main sequence star with a stellar classification of A2V, an apparent magnitude of +5.50 and an estimated age of 600 million years.[4] 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.[4] The secondary component has an apparent magnitude of 11.4 and is separated from the primary by an angle of 3.9 arcseconds.[8]
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.[4]
This star system is a probable member of the Ursa Major Moving Group of stars that share a common motion through space.[5] The space velocity components of Epsilon Trianguli are [U, V, W] = [+11.8, +11.4, –3.8] km/s.[9]
[edit] References
- ^ 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. doi:10.1051/0004-6361:20078357.
- ^ a b c Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99), Bibcode 1966CoLPL...4...99J
- ^ Wilson, Ralph Elmer (1953), General catalogue of stellar radial velocities, Carnegie Institution of Washington, Bibcode 1953QB901.W495.....
- ^ 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
- ^ a b Monier, R. (November), "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
- ^ 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
- ^ "eps Tri -- Variable Star", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=epsilon+trianguli, retrieved 2011-12-13
- ^ 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, doi:10.1111/j.1365-2966.2008.13596.x
- ^ 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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