Epsilon Muscae

Epsilon Muscae, Latinized as ε Muscae, is a red giant star of spectral type M5III in the constellation Musca.^[5] It is a 4th magnitude star, visible to the naked eye under good observing conditions. It is about 330 light-years from the Earth.^[2]

Epsilon Muscae

A light curve for Epsilon Muscae, plotted from Hipparcos data[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Musca
Right ascension	12h 17m 34.27564s[2]
Declination	−67° 57′ 38.65252″[2]
Apparent magnitude (V)	4.0 – 4.3[3]
Characteristics
Evolutionary stage	asymptotic giant branch[4]
Spectral type	M5 III[5]
Variable type	SRb[3]
Astrometry
Radial velocity (Rv)	7.1±0.7[citation needed] km/s
Proper motion (μ)	RA: −230.607±0.187 mas/yr[2] Dec.: −26.206±0.263 mas/yr[2]
Parallax (π)	9.9915 ± 0.2 mas[2]
Distance	326 ± 7 ly (100 ± 2 pc)
Absolute magnitude (MV)	−0.77[6]
Details
Mass	2±0.3[7] M☉
Radius	116±9[7] R☉
Luminosity	1,738[2] L☉
Surface gravity (log g)	0.6±0.02[7] cgs
Temperature	3,470±125[7] K
Other designations
eps Mus, CPD−67 1931, HD 106849, HIP 59929, HR 4671, SAO 251830
Database references
SIMBAD	data

Originally a main-sequence star of around 2 solar masses,^[7] Epsilon Muscae is now on the asymptotic giant branch^[4] and has expanded to 117 times the Sun's diameter and 1,700 its luminosity.^[7] It is a semiregular variable, varying between visual magnitudes 4.0 and 4.3^[3] in eight distinct periods ranging from a month to over half a year in length.^[5] Its distance from the Earth is about the same as the Lower Centaurus–Crux subgroup of the Scorpius–Centaurus association, although it is moving much faster at around 100 km/s and does not share a common origin.^[8]

References

1. "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 15 October 2022.
2. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
3. Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 255195566.
4. Eggen, Olin J. (July 1992), "Asymptotic giant branch stars near the sun", Astronomical Journal, 104 (1): 275–313, Bibcode:1992AJ....104..275E, doi:10.1086/116239.
5. Tabur, V.; Bedding, T. R.; Kiss, L. L.; Moon, T. T.; Szeidl, B.; Kjeldsen, H. (2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society. 400 (4): 1945–1961. arXiv:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. S2CID 15358380.
6. 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, S2CID 119257644.
7. Kallinger, T.; Beck, P. G.; Hekker, S.; Huber, D.; Kuschnig, R.; Rockenbauer, M.; Winter, P. M.; Weiss, W. W.; Handler, G.; Moffat, A. F. J.; Pigulski, A.; Popowicz, A.; Wade, G. A.; Zwintz, K. (2019-04-01), "Stellar masses from granulation and oscillations of 23 bright red giants observed by BRITE-Constellation", Astronomy & Astrophysics, 624: A35, arXiv:1902.07531, Bibcode:2019A&A...624A..35K, doi:10.1051/0004-6361/201834514, ISSN 0004-6361.
8. Kaler, Jim. "Epsilon Muscae". Stars. University of Illinois. Retrieved 21 December 2013.