Eta Muscae, a blue-white giant star in Musca
Eta Muscae is a blue-white giant star in the constellation Musca. At 374 light years away, it shines at an apparent visual magnitude of 4.78.
Eta Muscae (HIP 64661)
Eta Muscae is a blue-white giant star in the constellation Musca. At 374 light years away, it shines at an apparent visual magnitude of 4.78. It is moving through the Galaxy at a speed of 19.1 km/s relative to the Sun.
Sky position: RA 13h 15.2m, Dec -67° 53.7'
Common designations: Eta Muscae, HR 4993, HD 114911, Gaia DR3 5845487808871992448, HIP 64661
Eta Muscae has the spectral type B7III+B7III. B-type stars are hot (about 10,000 to 30,000 K), luminous and blue-white. They are massive, short-lived stars, typically only tens of millions of years old, and are common in young clusters and OB associations. Its luminosity class III marks it as a giant: an evolved star that has left the main sequence and swollen to many times its original size.
How to find Eta Muscae in the sky
Eta Muscae lies in Musca. With a declination of -67° 53.7', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 22° N. Observers poleward of latitude 22° S see it as circumpolar: it never sets. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around May, which makes the weeks around that month the best time to observe it.
Tabulated data for Eta Muscae
Astrometry and spectroscopy
| Right Ascension (J2000) | 198.81223045° (13h 15.2m) |
| Declination (J2000) | -67.89459139° (-67° 53.7') |
| Galactic Longitude | 305.17754420° |
| Galactic Latitude | -5.12672336° |
| Proper motion RA | -30.52 mas/yr |
| Proper motion Dec | -9.18 mas/yr |
| Parallax | 8.72 ± 0.18 mas |
| Spectral Type | B7III+B7III |
| Radial Velocity | -8.00 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 4.69 | -0.61 |
| V | 4.78 | -0.52 |
| J | 4.95 | -0.35 |
| H | 5.03 | -0.27 |
| K | 4.99 | -0.31 |
Colour index B-V: -0.09
Derivations
- Heliocentric distance: 114.68 pc (374 light years) (2.0% margin of error)
- Absolute visual magnitude: -0.52
- Transverse velocity: 17.3 km/s
- Space velocity relative to the Sun: 19.1 km/s
- Galactic position (X, Y, Z): 65.8 pc, -93.4 pc, -10.2 pc
- Galactic velocity (U, V, W): -18.6 km/s, -3.0 km/s, -2.7 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.