HD 89744
Star in the constellation Ursa Major
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HD 89744 is a star in the northern circumpolar constellation of Ursa Major, positioned about 0.4° due south of the bright star μ UMa.[13] This object has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.73.[1] 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.[1] There are two known exoplanets orbiting this star.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major[1] |
| A | |
| Right ascension | 10h 22m 10.5619s[2] |
| Declination | +41° 13′ 46.310″[2] |
| Apparent magnitude (V) | 5.73[1] |
| B | |
| Right ascension | 10h 22m 14.8721s[3] |
| Declination | +41° 14′ 26.514″[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F7V[4] or F8IV[5] |
| B−V color index | 0.531±0.003[1] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −4.35±0.12[1] km/s |
| Proper motion (μ) | RA: −120.285(42) mas/yr[2] Dec.: −138.171(50) mas/yr[2] |
| Parallax (π) | 25.9334±0.0436 mas[2] |
| Distance | 125.8 ± 0.2 ly (38.56 ± 0.06 pc) |
| Absolute magnitude (MV) | 2.83[6] |
| B | |
| Proper motion (μ) | RA: −119.215(647) mas/yr[3] Dec.: −140.390(457) mas/yr[3] |
| Parallax (π) | 26.0070±0.4713 mas[3] |
| Distance | 125 ± 2 ly (38.5 ± 0.7 pc) |
| Details | |
| A | |
| Mass | 1.37±0.09[7] M☉ |
| Radius | 2.16+0.06 −0.01[8] R☉ |
| Luminosity | 6.38±0.02[9] L☉ |
| Surface gravity (log g) | 4.27±0.05[7] cgs |
| Temperature | 6,381±43[7] K |
| Metallicity [Fe/H] | 0.30±0.03[7] dex |
| Rotation | ~9 days[9] |
| Rotational velocity (v sin i) | 9.3[10] km/s |
| Age | 8.4[9] Gyr |
| B | |
| Mass | 0.076[11] M☉ |
| Other designations | |
| BD+41°2076, GJ 9326, HD 89744, HIP 50786, HR 4067, WDS J10222+4114[12] | |
| A: HD 89744A | |
| B: HD 89744B, 2MASS J10221489+4114266, Gaia DR3 804745827531820288 | |
| Database references | |
| SIMBAD | A |
| B | |
| Exoplanet Archive | data |
| ARICNS | data |
At various times the star HD 89744 has been assigned a stellar classification of F7V,[4][14] F7IV-V,[15] and F8IV,[5][1] suggesting it is an F-type main-sequence star that is evolving onto the subgiant branch. It is ~8.4[9] billion years old with an inactive chromosphere[15] and is spinning with a projected rotational velocity of 9.3 km/s.[10] The star is 2.16[8] times the size of the Sun with 1.4[7] 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[9] times the luminosity of the Sun from its photosphere at an effective temperature of 6,381 K.[7]
This star was identified as a member of the AB Doradus moving group by J. López-Santiago and collaborators in 2006.[16] It was later shown that its evolutionary state is incompatible with membership.[17]
In 2001, a faint co-moving companion was identified at an angular separation of 63.1″ from the primary.[18] This is equivalent to a linear projected separation of 2,456 AU (0.04 ly).[11] The companion, designated component B, is an L-class (~L0.5)[4] brown dwarf[18] with a mass of ~0.076 M☉.[11]
Planetary system
In April 2000, a planet was discovered using radial velocity measurements taken at Fred Lawrence Whipple Observatory and Lick Observatory.[14] The orbital parameters were updated in 2006 and 2007 using additional measurements.[19][20] A second candidate planet with a much longer period was discovered in 2019.[21]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >8.35±0.18 MJ | 0.917±0.009 | 256.78±0.02 | 0.677±0.003 | — | — |
| c (unconfirmed) | >5.36±4.57 MJ | 8.3±1.8 | 6,974±2,161 | 0.29±0.12 | — | — |
See also
- List of exoplanets discovered before 2000 - HD 89744 b