Alpha Microscopii

From Wikipedia, the free encyclopedia
α 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)8.2214 ± 0.6173[4] mas
Distance400 ± 30 ly
(122 ± 9 pc)
Absolute magnitude (MV)−0.45 ± 0.20[5]
Details
Mass3.13 ± 0.18[5] M☉
Radius16.4 ± 1.6[5] R☉
Luminosity160[6] L☉
Surface gravity (log g)2.47 ± 0.07[5] cgs
Temperature4,923[5] K
Metallicity [Fe/H]+0.03[5] dex
Age0.36 ± 0.07[5] Gyr
Other designations
α Mic, Alpha Mic, HJ 5224A, CCDM J20500-3347A, CD−34 14660, CPD−34 8799, GC 29026, HD 198232, HIP 102831, HR 7965, IDS 20437-3409 A, PPM 300665, SAO 212472, WDS 20500-3347A.[1][7]
Database references
SIMBADdata

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 8.2214 mas as seen from the Earth, it is located 400 ± 30 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.[5] The star is radiating 160[6] times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,923 K.[5]

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°.[7] It has no physical connection to the star described above.[6][7]

References[]

  1. ^ a b c d e f g h i j * alf Mic -- Star in double system, database entry, SIMBAD. Accessed on line September 4, 2008.
  2. ^ a b NSV 13329, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 4, 2008.
  3. ^ a b 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.
  4. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  5. ^ a b c d e f g h i 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, S2CID 9341088
  6. ^ a b c Kaler, James B. (September 21, 2007), "Alpha Microscopii", STARS, University of Illinois, retrieved 2017-08-14.
  7. ^ a b c 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.
Retrieved from ""