Star in the constellation Microscopium
α Microscopii
Location of α Microscopii (circled)
Observation dataEpoch J2000.0 Equinox J2000.0 (ICRS )
Constellation
Microscopium
Right ascension 20h 49m 58.0810s [ 1]
Declination
−33° 46′ 46.934″[ 1]
Apparent magnitude (V)4.89± 0.01[ 2]
Characteristics
Spectral type
G7 III[ 3] [ 4]
U−B color index
+0.73[ 5]
B−V color index
+1.00[ 5]
Astrometry Radial velocity (Rv )−14.50± 0.09[ 6] km/s Proper motion (μ) RA: +15.057 mas /yr [ 1] Dec.: −23.524 mas /yr [ 1] Parallax (π)8.2508± 0.1563 mas [ 7] Distance 395 ± 7 ly pc ) Absolute magnitude (MV )−0.45 ± 0.20 [ 8] Details[ 9] Mass 3.19± 0.32 M ☉ Radius 18.41± 1.38 R ☉ Luminosity 173± 25 L ☉ Surface gravity (log g )2.27± 0.11 cgs Temperature 4,881± 43 K Metallicity [Fe/H] −0.06± 0.04 dex Rotational velocity (v sin i )2.6± 2[ 10] Age 400[ 11] Myr Other designations α Mic , 27 G. Microscopii , CD −34°14660CPD −34°8799GC 29026HD 198232HIP 102831HR 7965SAO 212472WDS 20500-3347A[ 12] [ 13] Database references SIMBAD data
Alpha Microscopii (α Microscopii ) is a star in the southern constellation of Microscopium .[ 13] apparent visual magnitude of 4.89.[ 2] parallax shift of mas light years from the Sun , give or take 7 light years. The star is moving nearer to the Sun with a heliocentric radial velocity of km/s [ 6]
This is an evolved giant star of type G with a stellar classification of either G7 III[ 3] [ 4] million years , it has an estimated 3.19 times the mass of the Sun and has expanded to 18.4 times the Sun's radius .[ 9] Sun's luminosity from its expanded photosphere at an effective temperature of K [ 9]
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°.[ 14] [ 15] spectroscopic binary in 2014.[ 10]
References
^ a b c Brown, A. G. A. ; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties" . Astronomy & Astrophysics 649 : A1. arXiv :2012.01533 Bibcode :2021A&A...649A...1G . doi :10.1051/0004-6361/202039657 S2CID 227254300 . (Erratum: doi :10.1051/0004-6361/202039657e ) . Gaia EDR3 record for this source at VizieR .^ a b Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics . 355 : L27 – L30 . Bibcode :2000A&A...355L..27H . ISSN 0004-6361 . ^ a b Hoffleit, Dorrit; Shapley, Harlow (1937). "Spectroscopic absolute magnitudes of three hundred and seventy southern stars". Annals of Harvard College Observatory . 105 (3): 45– 68. Bibcode :1937AnHar.105...45H . ^ a b Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0 . Bibcode :1982mcts.book.....H . ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory . 4 : 99– 110. Bibcode :1966CoLPL...4...99J . ^ a b Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; Chavero, C.; Gómez, M.; Mauas, P. J. D. (26 January 2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets" . Astronomy & Astrophysics . 574 : A50. arXiv :1410.6422 Bibcode :2015A&A...574A..50J . doi :10.1051/0004-6361/201424474 eISSN 1432-0746 . ISSN 0004-6361 . ^ 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 .^ 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 . ^ a b c Ottoni, G.; Udry, S.; Ségransan, D.; Buldgen, G.; Lovis, C.; Eggenberger, P.; Pezzotti, C.; Adibekyan, V.; Marmier, M.; Mayor, M.; Santos, N. C.; Sousa, S. G.; Lagarde, N.; Charbonnel, C. (January 2022). "CORALIE radial-velocity search for companions around evolved stars (CASCADES): I. Sample definition and first results: Three new planets orbiting giant stars" . Astronomy & Astrophysics . 657 : A87. arXiv :2201.01528 Bibcode :2022A&A...657A..87O . doi :10.1051/0004-6361/202040078 ISSN 0004-6361 . ^ a b De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars: V. Southern stars⋆⋆⋆" . Astronomy & Astrophysics . 561 : A126. arXiv :1312.3474 Bibcode :2014A&A...561A.126D . doi :10.1051/0004-6361/201220762 ISSN 0004-6361 . ^ Demarque, Pierre; Woo, Jong-Hak; Kim, Yong-Cheol; Yi, Sukyoung K. (December 2004). "Y 2 Isochrones with an Improved Core Overshoot Treatment" . The Astrophysical Journal Supplement Series . 155 (2): 667– 674. arXiv :astro-ph/0409024 Bibcode :2004ApJS..155..667D . doi :10.1086/424966 ISSN 1538-4357 . ^ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino . 1 . Bibcode :1879RNAO....1.....G . ^ a b * alf Mic -- Star in double system , database entry, SIMBAD . Accessed on line September 4, 2008.^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog" . The Astronomical Journal . 122 (6): 3466– 3471. Bibcode :2001AJ....122.3466M . doi :10.1086/323920 ISSN 0004-6256 . ^ Kaler, James B. (September 21, 2007). "Alpha Microscopii" . STARS . University of Illinois . Retrieved 2017-08-14 .
