Beta Trianguli
 Location of β Trianguli (circled) |
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| Observation data Epoch J2000.0 Equinox J2000.0 |
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|---|---|
| Constellation | Triangulum |
| Right ascension | 02h 09m 32.62712s[1] |
| Declination | +34° 59′ 14.2694″[1] |
| Apparent magnitude (V) | +3.00[2] |
| Characteristics | |
| Spectral type | A5III[3] |
| U−B color index | +0.11[2] |
| B−V color index | +0.14[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.9[4] km/s |
| Proper motion (μ) | RA: 149.16[1] mas/yr Dec.: –39.10[1] mas/yr |
| Parallax (π) | 25.71 ± 0.34[1] mas |
| Distance | 127 ± 2 ly (38.9 ± 0.5 pc) |
| Details | |
| Rotational velocity (v sin i) | 70[5] km/s |
| Other designations | |
Beta Trianguli (β Trianguli, β Tri) is a binary star system in the constellation Triangulum, located about 127 light years from Earth.[1] Although the apparent magnitude is only 3.0,[2] it is the brightest star in the constellation Triangulum.[7] In combination with Alpha Trianguli, these stars were called Al Mīzān, which is Arabic for "The Scale Beam".[7] In Chinese traditional astronomy, it was the 9th star of Tien Ta Tseang (天大將軍九).[8]
The star Beta Trianguli has a stellar classification of A5III, indicating that it has evolved away from the main sequence and is now a giant star. It is among the least variable of the stars that were observed by the Hipparcos spacecraft, with a magnitude varying by only 0.0005.[9] This is a probable spectroscopic binary star system with an orbital period of 31.39 days and an eccentricity of 0.43.[10] They are separated by a distance of less than 5 AU.[11]
Based on observations using the Spitzer Space Telescope, as reported in 2005, this system is emitting an excess of infrared radiation. This emission can be explained by a circumbinary ring of dust orbiting at a distance of about 10–20 AU from the stars. The dust is emitting infrared radiation at a blackbody temperature of 100 K.[11]
[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 d 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
- ^ 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
- ^ Wilson, Ralph Elmer (1953), General catalogue of stellar radial velocities, Carnegie Institution of Washington, Bibcode 1953QB901.W495.....
- ^ Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, Bibcode 2002A&A...393..897R, doi:10.1051/0004-6361:20020943
- ^ "bet Tri -- Spectroscopic binary", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Beta+Trianguli, retrieved 2011-12-12
- ^ a b Garfinkle, Robert A. (1997), Star-Hopping: Your Visa to Viewing the Universe, Cambridge University Press, p. 238, ISBN 0521598893, http://books.google.com/books?id=40JzBYGREL0C&pg=PA238
- ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 10 日
- ^ Adelman, S. J. (February 2001), "Research Note Hipparcos photometry: The least variable stars", Astronomy and Astrophysics 367: 297–298, Bibcode 2001A&A...367..297A, doi:10.1051/0004-6361:20000567
- ^ 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
- ^ a b Stansberry, J. A. et al. (2005), "A Spitzer Survey for Debris Disks in Binary Star Systems", Protostars and Planets V, Proceedings of the Conference held October 24-28, 2005, in Hilton Waikoloa Village, Hawai'i, Bibcode 2005prpl.conf.8613S
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