HD 89744
HD 89744 is a star in the northern circumpolar constellation of Ursa Major, positioned about 0.4° due south of the bright star Tania Australis (μ UMa). This object has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.73. The distance to this star has been measured using the parallax method, which locates it 126 light years from the Sun. It is drifting closer with a radial velocity of −4.4 km/s. There are two known exoplanets orbiting this star.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| A | |
| Right ascension | 10h 22m 10.5619s |
| Declination | +41° 13′ 46.310″ |
| Apparent magnitude (V) | 5.73 |
| B | |
| Right ascension | 10h 22m 14.8721s |
| Declination | +41° 14′ 26.514″ |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F7V or F8IV |
| B−V color index | 0.531±0.003 |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −4.35±0.12 km/s |
| Proper motion (μ) | RA: −120.285(42) mas/yr Dec.: −138.171(50) mas/yr |
| Parallax (π) | 25.9334 ± 0.0436 mas |
| Distance | 125.8 ± 0.2 ly (38.56 ± 0.06 pc) |
| Absolute magnitude (MV) | 2.83 |
| B | |
| Proper motion (μ) | RA: −119.215(647) mas/yr Dec.: −140.390(457) mas/yr |
| Parallax (π) | 26.0070 ± 0.4713 mas |
| Distance | 125 ± 2 ly (38.5 ± 0.7 pc) |
| Details | |
| A | |
| Mass | 1.37±0.09 M☉ |
| Radius | 2.16+0.06 −0.01 R☉ |
| Luminosity | 6.38±0.02 L☉ |
| Surface gravity (log g) | 4.27±0.05 cgs |
| Temperature | 6,381±43 K |
| Metallicity [Fe/H] | 0.30±0.03 dex |
| Rotation | ~9 days |
| Rotational velocity (v sin i) | 9.3 km/s |
| Age | 8.4 Gyr |
| B | |
| Mass | 0.076 M☉ |
| Other designations | |
| A: HD 89744A | |
| B: Gaia DR3 804745827531820288, HD 89744B, 2MASS J10221489+4114266 | |
| Database references | |
| A | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
| B | |
| SIMBAD | data |
At various times the star HD 89744 has been assigned a stellar classification of F7V, F7IV-V, and F8IV, suggesting it is an F-type main-sequence star that is evolving onto the subgiant branch. It is ~8.4 billion years old with an inactive chromosphere and is spinning with a projected rotational velocity of 9.3 km/s. The star is 2.16 times the size of the Sun with 1.4 times the Sun's radius. It is a high metallicity star, showing a greater abundance of heavier elements than in the Sun. The star is radiating 6.4 times the luminosity of the Sun from its photosphere at an effective temperature of 6,381 K.
This star was identified as a member of the AB Doradus moving group by J. López-Santiago and collaborators in 2006. It was later shown that its evolutionary state is incompatible with membership.
In 2001, a faint co-moving companion was identified at an angular separation of 63.1″ from the primary. This is equivalent to a linear projected separation of 2,456 AU (0.04 ly). The companion, designated component B, is an L-class (~L0.5) brown dwarf with a mass of ~0.076 M☉.