AV Microscopii

AV Microscopii

A broad-band optical light curve for AV Microscopii, plotted from data published by Tabur et al. (2009)[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 20h 41m 24.66513s[2]
Declination −42° 08′ 01.6196″[2]
Apparent magnitude (V) 6.28[3] (6.25 – 6.35)[4]
Characteristics
Spectral type M4 III[5]
B−V color index 1.584±0.019[3]
Variable type LC:[4]
Astrometry
Radial velocity (Rv)−22.9±0.9[3] km/s
Proper motion (μ) RA: +46.627[2] mas/yr
Dec.: −32.891[2] mas/yr
Parallax (π)4.3815 ± 0.1715 mas[2]
Distance740 ± 30 ly
(228 ± 9 pc)
Absolute magnitude (MV)−1.40[3]
Details
Radius77.5+3.2
−16.4[2] R☉
Luminosity849±38[2] L☉
Temperature3,539+448
−70[2] K
Other designations
AV Mic, CD−42°15034, HD 196829, HIP 102096, SAO 230323[6]
Database references
SIMBADdata

AV Microscopii is a variable star in the southern constellation of Microscopium. It is a dim, red-hued star near the lower limit of visibility to the naked eye with a baseline apparent visual magnitude of 6.28.[3] The star is located approximately 740 light years away from the Sun, based on parallax,[2] but is moving closer with a radial velocity of −23 km/s.[3] It is a member of the Milky Way's old disk population.[7]

Based upon a stellar classification of M4 III,[5] this is an aging red giant star,[5] having exhausted the supply of hydrogen at its core then expanded to around 78[2] times the Sun's radius. Earlier it had been classed as M3 II,[8] with the luminosity class of a bright giant. Samus et al. (2017) have it tentatively classified as an irregular variable of subtype LC, suggesting this is a supergiant star.[4] It is a pulsating variable with multiple periods discovered,[1] ranging in apparent visual magnitude between 6.25 and 6.35.[4][9] The star radiates 849 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,539 K.[2]

Pulsation periods[1]
Period (days) 22.3 23.3 30.3 31.0 32.3 45.0 110.7
Amplitude (mag.) 0.038 0.050 0.017 0.027 0.019 0.025 0.018
  1. ^ a b c Cite error: The named reference Tabur2009 was invoked but never defined (see the help page).
  2. ^ a b c d e f g h i j k Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Eggen1976 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Evans1959 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference AAVSOAV was invoked but never defined (see the help page).