44 Ophiuchi is a single[10] star in the constellation Ophiuchus. It has the Bayer designation b Ophiuchi, while 44 Ophiuchi is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.16.[2] The distance to this object is approximately 83.2 light years based on parallax.[1] It is drifting closer to the Earth with a heliocentric radial velocity of -37.2 km/s,[5] and is predicted to come within 30 light-years around 585,000 years from now.[11]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 17h 26m 22.21749s[1] |
Declination | −24° 10′ 31.1190″[1] |
Apparent magnitude (V) | 4.16[2] |
Characteristics | |
Spectral type | kA5hA9mF1III[3] |
U−B color index | +0.12[4] |
B−V color index | +0.28[4] |
Astrometry | |
Radial velocity (Rv) | −37.20[5] km/s |
Proper motion (μ) | RA: +0.10[1] mas/yr Dec.: −118.18[1] mas/yr |
Parallax (π) | 39.22 ± 0.24 mas[1] |
Distance | 83.2 ± 0.5 ly (25.5 ± 0.2 pc) |
Absolute magnitude (MV) | 2.13[2] |
Details | |
Mass | 1.77[6] M☉ |
Radius | 1.9[7] R☉ |
Luminosity | 13[6] L☉ |
Surface gravity (log g) | 4.15[8] cgs |
Temperature | 7,559[8] K |
Metallicity [Fe/H] | +0.30[2] dex |
Rotational velocity (v sin i) | 78[6] km/s |
Age | 1.028[8] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
This is an Am star with a stellar classification of kA5hA9mF1III,[3] indicating it has the luminosity class of a giant star with a spectrum that matches an A5 star based on the calcium K line, and an A9 star from the hydrogen and metal lines. It is around a billion years old[8] with 1.77[6] times the mass of the Sun and 1.9[7] times the Sun's girth. The star is radiating 13[6] times the Sun's luminosity from its photosphere at an effective temperature of 7,559 K.[8] It retains a moderately high rotation rate, showing a projected rotational velocity of 78 km/s.[6]