| 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 |
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]
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.
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
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