Summary
Eta Muscae is a multiple[9][10] star system in the southern constellation of Musca. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.79.[3] The system is located around 406 light years away from the Sun.[6] It is a member of the Lower Centaurs Crux subgroup of the Sco OB2 stellar association of co-moving stars.[11]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Musca |
| Right ascension | 13h 15m 14.94123s[2] |
| Declination | −67° 53′ 40.5276″[2] |
| Apparent magnitude (V) | 4.79[3] |
| Characteristics | |
| Spectral type | B8V + sim. + K9.4XR? + A0p[4] or B7III + B7III[5] |
| B−V color index | −0.078±0.003[3] |
| Variable type | eclipsing binary |
| Astrometry | |
| Radial velocity (Rv) | −8.1±7.4[3] km/s |
| Proper motion (μ) | RA: +30.207[2] mas/yr Dec.: +17.921[2] mas/yr |
| Parallax (π) | 7.1001 ± 0.1924 mas[2] |
| Distance | 405.7[6] ly (124.4[6] pc) |
| Absolute magnitude (MV) | −0.81[6] |
| Orbit[7] | |
| Period (P) | 2.3963161 d |
| Semi-major axis (a) | 14.11±0.15 R☉ |
| Eccentricity (e) | 0.00 |
| Inclination (i) | 77.40° |
| Semi-amplitude (K1) (primary) | 145.35±0.20 km/s |
| Semi-amplitude (K2) (secondary) | 145.38±0.20 km/s |
| Details[7] | |
| Eta Mus Aa | |
| Mass | 3.30±0.04 M☉ |
| Radius | 2.14±0.02 R☉ |
| Luminosity | 223.77[3] (combined) L☉ |
| Surface gravity (log g) | 4.293±0.005 cgs |
| Temperature | 12,700±100 K |
| Rotational velocity (v sin i) | 34±2 km/s |
| Eta Mus Ab | |
| Mass | 3.29±0.04 M☉ |
| Radius | 2.13±0.04 R☉ |
| Surface gravity (log g) | 4.298±0.005 cgs |
| Temperature | 12,550±300 K |
| Rotational velocity (v sin i) | 44±2 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
The two main components of this system form a double-lined spectroscopic binary[12] with a period of 2.4 days in a circular orbit.[7][11] They are a detached eclipsing binary with a spectral type of B8V and a brightness that dips by 0.05 magnitude once per orbit.[13] This pair consists of two components of similar mass and type.[4]
Further away from the primary system are stars of magnitude 7.3 and 10, designated Eta Muscae B and C. It is unclear if these stars are gravitationally–bound to the main pair. Evidence for an additional component has been found with a 30-year cycle in the orbital behavior of the main pair.[9] The data suggests an orbital eccentricity of 0.29 for this suspected component, Eta Muscae D.[14]
References edit
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ a b c d e 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.
- ^ a b c d e 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.
- ^ a b 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.
- ^ Hube, Douglas P. (1970). "The radial velocities of 335 late B-type stars". Memoirs of the Royal Astronomical Society. 72: 233. Bibcode:1970MmRAS..72..233H.
- ^ a b c d Hubrig, S.; et al. (June 2001). "Search for low-mass PMS companions around X-ray selected late B stars". Astronomy and Astrophysics. 372: 152–164. arXiv:astro-ph/0103201. Bibcode:2001A&A...372..152H. doi:10.1051/0004-6361:20010452. S2CID 17507782.
- ^ a b c Eker, Z.; et al. (May 2014). "The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way". Publications of the Astronomical Society of Australia. 31: 23. arXiv:1403.1583. Bibcode:2014PASA...31...24E. doi:10.1017/pasa.2014.17. S2CID 119238300. e024.
- ^ "eta Mus". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-26.
{{cite web}}: CS1 maint: postscript (link) - ^ a b Butland, R. J.; Budding, E. (2011). "Another component in the multiple system Eta Mus". Commissions 27 and 42 of the IAU Information Bulletin on Variable Stars. 6004 (6004): 1. Bibcode:2011IBVS.6004....1B. Archived from the original on December 21, 2013.
- ^ Medici, A.; Hubrig, S. (January 2000). "Triple System epsilon Vol and Quadruple System eta Mus: the Mass Ratio in Close Binary Systems". Information Bulletin on Variable Stars. 4827: 1. Bibcode:2000IBVS.4827....1M.
- ^ a b Hensberge, H.; et al. (April 5–10, 2003). Lépine, Jacques; Gregorio-Hetem, Jane (eds.). η Muscae: a multiple system with a PMS component. Open Issues in Local Star Formation. Proceedings of the Ouro Preto Colloquium, Brazil. Astrophysics and Space Science Library. Vol. 299. Kluwer Academic Publishers, Dordrecht. Bibcode:2003ASSL..299P...8H.
- ^ Buscombe, W.; Morris, Pamela M. (1961). "Three southern spectroscopic binaries". Monthly Notices of the Royal Astronomical Society. 123 (2): 183. Bibcode:1961MNRAS.123..183B. doi:10.1093/mnras/123.2.183.
- ^ Zasche, P.; et al. (2009). "A catalog of visual double and multiple stars with eclipsing components". The Astronomical Journal. 138 (2): 664–79. arXiv:0907.5172. Bibcode:2009AJ....138..664Z. doi:10.1088/0004-6256/138/2/664. S2CID 17089387.
- ^ Blackford, M. G.; et al. (June 2016). "The AD binary in the multiple system eta Mus". Information Bulletin on Variable Stars. 6171: 1. Bibcode:2016IBVS.6171....1B.