Alpha Microscopii

Quality 0.50 · 1 view · Updated 2 months ago

Star in the constellation Microscopium

title: "Alpha Microscopii" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["microscopium", "g-type-giants", "bayer-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "durchmusterung-objects", "double-stars", "bright-star-catalogue-objects", "gould-objects", "spectroscopic-binaries"] description: "Star in the constellation Microscopium" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Alpha_Microscopii" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Microscopium ::

| name = α Microscopii | image ={{Location mark | image=Microscopium IAU.svg | alt= | float=center | width=250 | label= | position=center | mark=Red circle.svg | mark_width=8 | mark_link=Alpha Microscopii | x = 550 | y = 400 | caption = Location of α Microscopii (circled) | epoch = J2000.0 (ICRS) | constell = Microscopium | ra = | dec = | appmag_v = 4.89 | class = G7 III or G8 III | u-b = +0.73 | b-v = +1.00 | radial_v = −14.50 | prop_mo_ra = +15.057 | prop_mo_dec = −23.524 | parallax = 8.2508 | p_error = 0.1563 | parallax_footnote = | absmag_v = −0.45 ± 0.20 | pm_footnote = | source = | rotational_velocity = 2.6 | temperature = 4,881 | luminosity = 173 | radius = 18.41 | mass = 3.19 | gravity = 2.27 | metal_fe = −0.06 | age_myr = 400 | names= | Simbad=alf+mic

Alpha Microscopii (α Microscopii) is a star in the southern constellation of Microscopium. It is visible to the naked eye with an apparent visual magnitude of 4.89. Based upon an annual parallax shift of 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

This is an evolved giant star of type G with a stellar classification of either G7 III or G8 III 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. The star is radiating 173 times the Sun's luminosity from its expanded photosphere at an effective temperature of , giving a yellow hue.

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°. It has no physical connection to the star described above. As for Alpha Microscopii, it was found to be a probable spectroscopic binary in 2014.

References

{{Cite Gaia EDR3. 6780065098938242304
(March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics.
(1937). "Spectroscopic absolute magnitudes of three hundred and seventy southern stars". Annals of Harvard College Observatory.
Houk, N.. (1982). "Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0.".
(1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory.
(26 January 2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics.
{{cite DR2. 6780006508937236096
(November 2006). "Basic physical parameters of a selected sample of evolved stars". Astronomy and Astrophysics.
(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.
(January 2014). "A catalog of rotational and radial velocities for evolved stars: V. Southern stars⋆⋆⋆". Astronomy & Astrophysics.
(December 2004). "Y 2 Isochrones with an Improved Core Overshoot Treatment". The Astrophysical Journal Supplement Series.
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.
{{SIMBAD link. alf+mic. * alf Mic -- Star in double system, database entry, [[SIMBAD]]. Accessed on line September 4, 2008.
(December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal.
Kaler, James B.. (September 21, 2007). "Alpha Microscopii". [[University of Illinois]].

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::