Alpha Microscopii
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Microscopium |
Right ascension | 20h 49m 58.0821s[1] |
Declination | −33° 46′ 47.000″[1] |
Apparent magnitude (V) | 4.88 to 4.94[2] |
Characteristics | |
Spectral type | G7III[1] |
U−B color index | +0.73[3] |
B−V color index | +1.00[3] |
Astrometry | |
Radial velocity (Rv) | −14.5 ± 0.9[1] km/s |
Proper motion (μ) | RA: 3.71[1] mas/yr Dec.: −20.19[1] mas/yr |
Parallax (π) | 8.62 ± 0.71[1] mas |
Distance | 380 ± 30 ly (116 ± 10 pc) |
Absolute magnitude (MV) | −0.45 ± 0.20[4] |
Details | |
Mass | 3.13 ± 0.18[4] M☉ |
Radius | 16.4 ± 1.6[4] R☉ |
Luminosity | 160[5] L☉ |
Surface gravity (log g) | 2.47 ± 0.07[4] cgs |
Temperature | 4,923[4] K |
Metallicity [Fe/H] | +0.03[4] dex |
Age | 0.36 ± 0.07[4] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Alpha Microscopii (α Microscopii) is a star in the southern constellation of Microscopium.[1] It is visible to the naked eye with an apparent visual magnitude that varies between 4.88 and 4.94.[2] Based upon an annual parallax shift of 8.62 mas as seen from the Earth, it is located roughly 380 light years from the Sun. The star is moving nearer to the Sun with a radial velocity of −15 km/s.[1]
This is an evolved giant star of type G with a stellar classification of G7 III.[1] At the age of 360 million years, it has an estimated 3.1 times the mass of the Sun and has expanded to around 16 times the Sun's radius.[4] The star is radiating 160[5] times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,923 K.[4]
This star has an optical visual companion, CCDM J20500-3347B, of apparent visual magnitude 10.0 approximately 20.4 arcseconds away at a position angle of 166°.[6] It has no physical connection to the star described above.[5][6]
References
- 1 2 3 4 5 6 7 8 9 10 11 * alf Mic -- Star in double system, database entry, SIMBAD. Accessed on line September 4, 2008.
- 1 2 NSV 13329, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 4, 2008.
- 1 2 HR 7965, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 4, 2008.
- 1 2 3 4 5 6 7 8 9 da Silva, L.; et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics, 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105
- 1 2 3 Kaler, James B. (September 21, 2007), "Alpha Microscopii", STARS, University of Illinois, retrieved 2017-08-14.
- 1 2 3 Entry 20500-3347, The Washington Double Star Catalog Archived September 8, 2008, at the Wayback Machine., United States Naval Observatory. Accessed on line September 4, 2008.