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Variable star in the constellation Musca From Wikipedia, the free encyclopedia
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]