Star in the constellation Microscopium
Alpha Microscopii (α Microscopii ) is a star in the southern constellation of Microscopium .[ 13] It is visible to the naked eye with an apparent visual magnitude of 4.89.[ 2] Based upon an annual parallax shift of 8.2508 mas as seen from the Earth, it is located 395 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 −15 km/s [ 6]
This is an evolved giant star of type G with a stellar classification of either G7 III[ 3] or G8 III[ 4] depending on the source. At the age of 400 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] The star is radiating 173 times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,881 K , giving a yellow hue.[ 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] It has no physical connection to the star described above.[ 15] As for Alpha Microscopii, it was found to be a probable spectroscopic binary in 2014.[ 10]
^ 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 .