Epsilon Microscopii

Epsilon Microscopii, Latinized from ε Microscopii, is a single,[10] white-hued star in the southern constellationof Microscopium. It is faintly visible to the naked eye with an apparent visual magnitude of 4.71.[2] The annual parallax shift of the star is 19.7054 mas[1] as measured from Earth, which yields a distance estimate of around 166 light years. It is moving further from the Sun with a radial velocity of +7 km/s.[5]

ε Microscopii
Location of ε Microscopii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Microscopium
Right ascension  21h 17m 56.28399s[1]
Declination −32° 10′ 21.1515″[1]
Apparent magnitude (V) 4.71[2]
Characteristics
Spectral type A1V[3]
U−B color index +0.02[4]
B−V color index +0.06[4]
Astrometry
Radial velocity (Rv)+7.20[5] km/s
Proper motion (μ) RA: +54.36[1] mas/yr
Dec.: −23.29[1] mas/yr
Parallax (π)19.7054 ± 0.5472[6] mas
Distance166 ± 5 ly
(51 ± 1 pc)
Absolute magnitude (MV)0.97[2]
Details
Mass2.18[7] M☉
Radius2.2[7] R☉
Luminosity35.62[2] L☉
Surface gravity (log g)4.37[8] cgs
Temperature9,126[8] K
Metallicity [Fe/H]−0.01[9] dex
Rotational velocity (v sin i)127[3] km/s
Age525[8] Myr
Other designations
ε Mic, CD−32° 16498, CPD−32° 6329, FK5 801, GC 29774, HD 202627, HIP 105140, HR 8135, SAO 212874
Database references
SIMBADdata

This star has a stellar classification of A1 V,[3] indicating it is an A-type main-sequence star that is generating energy through hydrogen fusion at its core. The spectrum displays an overabundance of silicon in the atmosphere,[11] but the abundance of iron is the same as in the Sun.[9] The star has 2.2 times the mass of the Sun and 2.2 times the Sun's radius.[7] It is around a half billion years old[8] and is spinning rapidly with a projected rotational velocity of 127 km/s.[3] Epsilon Microscopii is radiating about 36 times the Sun's luminosity[2] from its photosphere at an effective temperature of 9,126 K.[8]

Epsilon Microscopii was a latter designation of 4 Piscis Austrini.[12]

This star was the brightest star in Globus Aerostaticus, the obsolete constellation[13].

References
  1. Van Leeuwen, F. (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. Vizier catalog entry
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. Vizier catalog entry
  3. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  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. Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
  8. David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. Vizier catalog entry
  9. Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. Vizier catalog entry
  10. 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.
  11. Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi:10.1051/0004-6361/200810788.
  12. 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.
  13. Ian Ridpath's Star Tales - Globus Aerostaticus
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