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Gamma Microscopii

October 20, 2023

Gamma Microscopii (γ Microscopii, γ Mic) is the brightest star in the faint southern constellation of Microscopium.[8] It has an apparent visual magnitude of 4.68,[2] which is too dim to be viewed from city skies. The distance to this star has been determined using parallax measurements made with the Gaia telescope, which place it at 223 ± 8 light-years (68.4 ± 2.5 parsecs).

Gamma Microscopii
Location of γ Microscopii (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 21h 01m 17.46047s[1]
Declination −32° 15′ 27.9574″[1]
Apparent magnitude (V) 4.680[2]
Characteristics
Spectral type G6 III[3]
U−B color index +0.575[2]
B−V color index +0.882[2]
R−I color index +0.32[4]
Astrometry
Radial velocity (Rv)+17.6[5] km/s
Proper motion (μ) RA: −1.73[1] mas/yr
Dec.: +0.41[1] mas/yr
Parallax (π)14.6428 ± 0.4966 mas[6]
Distance223 ± 8 ly
(68 ± 2 pc)
Absolute magnitude (MV)0.49[7]
Details
Mass2.5[8] M☉
Radius10[8] R☉
Luminosity64[8] L☉
Surface gravity (log g)3.34[9] cgs
Temperature5,050[9] K
Metallicity [Fe/H]–0.22 ± 0.11[10] dex
Age620[8] Myr
Other designations
Gamma Microscopii, Gamma Mic, γ Mic, CD−32 16353, CPD−32 6269, FK5 1550, GC 29331, HD 199951, HIP 103738, HR 8039, SAO 212636, WDS 21013-3215A.[11][12]
Database references
SIMBADdata

Based upon a stellar classification of G6 III,[3] this is a G-type giant star. It is a core helium fusing star that is classified as a member of the red clump evolutionary branch, although the metallicity of this star—meaning the abundance of elements other than hydrogen and helium—is anomalously low for a member of this group.[10] The effective temperature of the star's outer envelope is 5,050 K,[9] giving it the yellow-hued glow typical of G-type stars.[13]

In the galactic coordinate system, this star has space velocity components of [U, V, W] = [+13.75, +3.47, –10.50] km s−1. The peculiar velocity of this star, relative to its neighbors, is 1.2 km s−1. It has been listed as likely member of the Ursa Major Moving Group of stars that share a similar location and a common trajectory through space.[7] Backwards extrapolation of the motion of γ Microscopii has shown that approximately 3.8 million years ago, it was only around 6 light-years from the Sun.[14] It would then have had an apparent magnitude of −3 and have been brighter than Sirius is now.[8] Shortly before that, around 3.9 million years ago, it likely passed within 1.14 to 3.45 light-years of the Sun, possibly massive enough and close enough to disturb the Oort cloud.[15] The same authors looked at Proper Motion Data collected with Gaia DR2 and didn't confirm the close encounter based on that dataset. Additional information is needed to identify the root cause for the mismatch between Hipparcos and Gaia datasets in that case.[16]

Gamma Microscopii has a visual companion, CCDM J21013-3215B at an angular separation of 26 arcseconds along a position angle of 94°, with an apparent visual magnitude of approximately 13.7.[12] Most likely this star is not gravitationally bound to γ Microscopii, but is merely a line of sight companion.[8][17]

The Bayer designation γ Microscopii was not assigned by Bayer himself. It was given the Flamsteed designation of 1 Piscis Austrini before Lacaille created the constellation of Microscopium in 1756.[18]

References Edit

  1. ^ a b c d van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
  2. ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667
  3. ^ a b Montes, D.; et al. (November 2001), (PDF), Monthly Notices of the Royal Astronomical Society, 328 (1): 45–63, arXiv:astro-ph/0106537, Bibcode:2001MNRAS.328...45M, doi:10.1046/j.1365-8711.2001.04781.x, S2CID 55727428, archived from the original (PDF) on 2017-09-22, retrieved 2018-11-04
  4. ^ HR 8039, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 20, 2008.
  5. ^ Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  6. ^ 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.
  7. ^ a b King, Jeremy R.; et al. (April 2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980–2017, Bibcode:2003AJ....125.1980K, doi:10.1086/368241
  8. ^ a b c d e f g Gamma Mic, Stars, Jim Kaler. Accessed on line March 19, 2015.
  9. ^ a b c McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527
  10. ^ a b Kubiak, M.; et al. (June 2002), "Metal Abundance of Red Clump Stars in Baade's Window", Acta Astronomica, 52: 159–175, Bibcode:2002AcA....52..159K
  11. ^ * gam Mic -- Star in double system, database entry, SIMBAD. Accessed on line November 20, 2008.
  12. ^ a b Entry 21013-3215, The Washington Double Star Catalog 2009-01-31 at the Wayback Machine, United States Naval Observatory. Accessed on line November 20, 2008.
  13. ^ , Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
  14. ^ García-Sánchez, J.; Weissman, P. R.; Preston, R. A.; Jones, D. L.; Lestrade, J.-F.; Latham, D. W.; Stefanik, R. P.; Paredes, J. M. (2001), "Stellar encounters with the solar system" (PDF), Astronomy and Astrophysics, 379 (2): 634–659, Bibcode:2001A&A...379..634G, doi:10.1051/0004-6361:20011330
  15. ^ Bailer-Jones, C. A. L. (2015). "Close encounters of the stellar kind". Astronomy & Astrophysics. 575: 13. arXiv:1412.3648. Bibcode:2015A&A...575A..35B. doi:10.1051/0004-6361/201425221. S2CID 59039482. A35.
  16. ^ Bailer-Jones, C. A. L.; Rybizki, J.; Andrae, R.; Fouesneau, M. (19 May 2018). "New stellar encounters discovered in the second Gaia data release". Astronomy & Astrophysics. 616 (37): A37. arXiv:1805.07581. Bibcode:2018A&A...616A..37B. doi:10.1051/0004-6361/201833456. S2CID 56269929.
  17. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  18. ^ Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 220. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305. S2CID 118445625.

October 20, 2023
gamma, microscopii, microscopii, brightest, star, faint, southern, constellation, microscopium, apparent, visual, magnitude, which, viewed, from, city, skies, distance, this, star, been, determined, using, parallax, measurements, made, with, gaia, telescope, w. Gamma Microscopii g Microscopii g Mic is the brightest star in the faint southern constellation of Microscopium 8 It has an apparent visual magnitude of 4 68 2 which is too dim to be viewed from city skies The distance to this star has been determined using parallax measurements made with the Gaia telescope which place it at 223 8 light years 68 4 2 5 parsecs Gamma MicroscopiiLocation of g Microscopii circled Observation dataEpoch J2000 0 Equinox J2000 0 ICRS Constellation MicroscopiumRight ascension 21h 01m 17 46047s 1 Declination 32 15 27 9574 1 Apparent magnitude V 4 680 2 CharacteristicsSpectral type G6 III 3 U B color index 0 575 2 B V color index 0 882 2 R I color index 0 32 4 AstrometryRadial velocity Rv 17 6 5 km sProper motion m RA 1 73 1 mas yr Dec 0 41 1 mas yrParallax p 14 6428 0 4966 mas 6 Distance223 8 ly 68 2 pc Absolute magnitude MV 0 49 7 DetailsMass2 5 8 M Radius10 8 R Luminosity64 8 L Surface gravity log g 3 34 9 cgsTemperature5 050 9 KMetallicity Fe H 0 22 0 11 10 dexAge620 8 MyrOther designationsGamma Microscopii Gamma Mic g Mic CD 32 16353 CPD 32 6269 FK5 1550 GC 29331 HD 199951 HIP 103738 HR 8039 SAO 212636 WDS 21013 3215A 11 12 Database referencesSIMBADdataBased upon a stellar classification of G6 III 3 this is a G type giant star It is a core helium fusing star that is classified as a member of the red clump evolutionary branch although the metallicity of this star meaning the abundance of elements other than hydrogen and helium is anomalously low for a member of this group 10 The effective temperature of the star s outer envelope is 5 050 K 9 giving it the yellow hued glow typical of G type stars 13 In the galactic coordinate system this star has space velocity components of U V W 13 75 3 47 10 50 km s 1 The peculiar velocity of this star relative to its neighbors is 1 2 km s 1 It has been listed as likely member of the Ursa Major Moving Group of stars that share a similar location and a common trajectory through space 7 Backwards extrapolation of the motion of g Microscopii has shown that approximately 3 8 million years ago it was only around 6 light years from the Sun 14 It would then have had an apparent magnitude of 3 and have been brighter than Sirius is now 8 Shortly before that around 3 9 million years ago it likely passed within 1 14 to 3 45 light years of the Sun possibly massive enough and close enough to disturb the Oort cloud 15 The same authors looked at Proper Motion Data collected with Gaia DR2 and didn t confirm the close encounter based on that dataset Additional information is needed to identify the root cause for the mismatch between Hipparcos and Gaia datasets in that case 16 Gamma Microscopii has a visual companion CCDM J21013 3215B at an angular separation of 26 arcseconds along a position angle of 94 with an apparent visual magnitude of approximately 13 7 12 Most likely this star is not gravitationally bound to g Microscopii but is merely a line of sight companion 8 17 The Bayer designation g Microscopii was not assigned by Bayer himself It was given the Flamsteed designation of 1 Piscis Austrini before Lacaille created the constellation of Microscopium in 1756 18 References Edit a b c d van Leeuwen F November 2007 Validation of the new Hipparcos reduction Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 a b c d Jennens P A Helfer H L September 1975 A new photometric metal abundance and luminosity calibration for field G and K giants Monthly Notices of the Royal Astronomical Society 172 3 667 679 Bibcode 1975MNRAS 172 667J doi 10 1093 mnras 172 3 667 a b Montes D et al November 2001 Late type members of young stellar kinematic groups I Single stars PDF Monthly Notices of the Royal Astronomical Society 328 1 45 63 arXiv astro ph 0106537 Bibcode 2001MNRAS 328 45M doi 10 1046 j 1365 8711 2001 04781 x S2CID 55727428 archived from the original PDF on 2017 09 22 retrieved 2018 11 04 HR 8039 database entry The Bright Star Catalogue 5th Revised Ed Preliminary Version D Hoffleit and W H Warren Jr CDS ID V 50 Accessed on line November 20 2008 Wilson Ralph Elmer 1953 General Catalogue of Stellar Radial Velocities Carnegie Institute Washington D C Publication Washington Carnegie Institution of Washington Bibcode 1953GCRV C 0W Brown A G A et al Gaia collaboration August 2018 Gaia Data Release 2 Summary of the contents and survey properties Astronomy amp Astrophysics 616 A1 arXiv 1804 09365 Bibcode 2018A amp A 616A 1G doi 10 1051 0004 6361 201833051 Gaia DR2 record for this source at VizieR a b King Jeremy R et al April 2003 Stellar Kinematic Groups II A Reexamination of the Membership Activity and Age of the Ursa Major Group The Astronomical Journal 125 4 1980 2017 Bibcode 2003AJ 125 1980K doi 10 1086 368241 a b c d e f g Gamma Mic Stars Jim Kaler Accessed on line March 19 2015 a b c McWilliam Andrew December 1990 High resolution spectroscopic survey of 671 GK giants I Stellar atmosphere parameters and abundances Astrophysical Journal Supplement Series 74 1075 1128 Bibcode 1990ApJS 74 1075M doi 10 1086 191527 a b Kubiak M et al June 2002 Metal Abundance of Red Clump Stars in Baade s Window Acta Astronomica 52 159 175 Bibcode 2002AcA 52 159K gam Mic Star in double system database entry SIMBAD Accessed on line November 20 2008 a b Entry 21013 3215 The Washington Double Star Catalog Archived 2009 01 31 at the Wayback Machine United States Naval Observatory Accessed on line November 20 2008 The Colour of Stars Australia Telescope Outreach and Education Commonwealth Scientific and Industrial Research Organisation December 21 2004 archived from the original on 2012 03 18 retrieved 2012 01 16 Garcia Sanchez J Weissman P R Preston R A Jones D L Lestrade J F Latham D W Stefanik R P Paredes J M 2001 Stellar encounters with the solar system PDF Astronomy and Astrophysics 379 2 634 659 Bibcode 2001A amp A 379 634G doi 10 1051 0004 6361 20011330 Bailer Jones C A L 2015 Close encounters of the stellar kind Astronomy amp Astrophysics 575 13 arXiv 1412 3648 Bibcode 2015A amp A 575A 35B doi 10 1051 0004 6361 201425221 S2CID 59039482 A35 Bailer Jones C A L Rybizki J Andrae R Fouesneau M 19 May 2018 New stellar encounters discovered in the second Gaia data release Astronomy amp Astrophysics 616 37 A37 arXiv 1805 07581 Bibcode 2018A amp A 616A 37B doi 10 1051 0004 6361 201833456 S2CID 56269929 Eggleton P P Tokovinin A A September 2008 A catalogue of multiplicity among bright stellar systems Monthly Notices of the Royal Astronomical Society 389 2 869 879 arXiv 0806 2878 Bibcode 2008MNRAS 389 869E doi 10 1111 j 1365 2966 2008 13596 x S2CID 14878976 Wagman M August 1987 Flamsteed s Missing Stars Journal for the History of Astronomy 18 3 220 Bibcode 1987JHA 18 209W doi 10 1177 002182868701800305 S2CID 118445625 Retrieved from https en wikipedia org w index php title Gamma Microscopii amp oldid 1176950890, wikipedia, wiki, book, books, library,

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