Beta Microscopii

β Microscopii
Location of β Microscopii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 20h 51m 58.7618s[1]
Declination −33° 10′ 40.7051″[1]
Apparent magnitude (V) 6.05±0.01[2]
Characteristics
Spectral type A1 IV[3]
B−V color index +0.03[4]
Astrometry
Radial velocity (Rv)−12±4.3[5] km/s
Proper motion (μ) RA: +7.712 mas/yr[1]
Dec.: −5.568 mas/yr[1]
Parallax (π)6.5022 ± 0.0451 mas[1]
Distance502 ± 3 ly
(154 ± 1 pc)
Absolute magnitude (MV)+0.22[6]
Details
Mass2.96[7] M☉
Radius3.5±0.1[8] R☉
Luminosity77.25[6] L☉
Surface gravity (log g)3.58[9] cgs
Temperature8,942[10] K
Metallicity [Fe/H]0.00[11] dex
Rotational velocity (v sin i)275±3[12] km/s
Age337[11] Myr
Other designations
β Mic, 32 Microscopii[13], CD−33° 15245, HD 198529, HIP 102989, HR 7979, SAO 212499[14]
Database references
SIMBADdata

Beta Microscopii (Beta Mic), Latinized from β Microscopii, is a solitary star in the constellation Microscopium. It is close to the lower limit of stars that are visible to the naked eye having an apparent visual magnitude of 6.05[2] Based upon an annual parallax shift of 6.5022 mas as seen from Earth,[1] this star is located 502 light years away[1] from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.19 due to interstellar dust.[11]

Beta Mic has a stellar classification of A1 IV,[3] indicating that it is an evolved A-type subgiant. Older sources give it a class of A2 Vn,[15] suggesting that it is an A-type main-sequence star with nebulous absorption lines due to rapid rotation. Consistent with the older classification, the star is spinning rapidly with a projected rotational velocity of 275 km/s.[12] The star has 2.96 times the mass of the Sun[7] and due to its evolved status, has a radius of 3.5 R☉.[8] It radiates at 77.2 times the luminosity of the Sun[6] from its photosphere at an effective temperature of 8,942 K,[10] giving a white hue. Beta Mic has a solar metallicity and is estimated to be around 340 million years old.[11]

  1. ^ a b c d e f Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1982 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Corben1968 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Kervella2021 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Stassun2019 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Steinmetz2020 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Anders2022 was invoked but never defined (see the help page).
  11. ^ a b c d Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Díaz2011 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Evans1966 was invoked but never defined (see the help page).