HD 119124
Binary star in the constellation Ursa Major From Wikipedia, the free encyclopedia
HD 119124 is a wide binary star[21] system in the circumpolar constellation of Ursa Major. With an apparent visual magnitude of 6.3,[3] it lies below the normal brightness limit of stars that are visible with the naked eye under most viewing conditions. An annual parallax shift of 39.18 masfor the A component provides a distance estimate of 83 light years. The pair are candidate members of the Castor Moving Group,[22] which implies a relatively youthful age of around 200 million years.[15] HD 119124 is moving closer to the Sun with a radial velocity of −12 km/s.[8]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major[1] |
| A | |
| Right ascension | 13h 40m 23.2321s[2] |
| Declination | +50° 31′ 09.894″[2] |
| Apparent magnitude (V) | 6.32[3] |
| B | |
| Right ascension | 13h 40m 24.5187s[4] |
| Declination | +50° 30′ 57.569″[4] |
| Apparent magnitude (V) | 10.51[5] |
| Characteristics | |
| Spectral type | F8 V[6] + K7[7] |
| U−B color index | −0.01[3] |
| B−V color index | +0.52[3] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −12.2±0.3[8] km/s |
| Proper motion (μ) | RA: −125.559[2] mas/yr Dec.: +58.708[2] mas/yr |
| Parallax (π) | 39.1793±0.0254 mas[2] |
| Distance | 83.25 ± 0.05 ly (25.52 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.30[9] |
| B | |
| Proper motion (μ) | RA: −130.953[4] mas/yr Dec.: +59.421[4] mas/yr |
| Parallax (π) | 39.2733 ± 0.0165 mas[4] |
| Distance | 83.05 ± 0.03 ly (25.46 ± 0.01 pc) |
| Absolute magnitude (MV) | 8.59[10] |
| Details | |
| A | |
| Mass | 1.15[11] M☉ |
| Radius | 1.1[12] R☉ |
| Luminosity | 1.5[12] L☉ |
| Surface gravity (log g) | 4.24[2] cgs |
| Temperature | 6,149[13] K |
| Metallicity [Fe/H] | −0.18[13] dex |
| Rotation | 4.42[14] days |
| Rotational velocity (v sin i) | 10.2[15] km/s |
| Age | 2.06±22[15] Gyr |
| B | |
| Mass | 0.63[11] M☉ |
| Radius | 0.6[4] R☉ |
| Luminosity | 0.087[4] L☉ |
| Surface gravity (log g) | 4.52[4] cgs |
| Temperature | 4,130[16] K |
| Metallicity [Fe/H] | 0.21[17] dex |
| Other designations | |
| STF 1774, BD+51°1859, GJ 521.2, GJ 9457, HD 119124, HIP 66704, HR 5148, ADS 8992, CCDM J13404+5031, WDS J13404+5031[18] | |
| A: SAO 28836[19] | |
| B: TYC 3469-1423-1, 2MASS J13402450+5030576[20] | |
| Database references | |
| SIMBAD | data |
| B | |
This system was first identified as a double star by Friedrich von Struve (1793−1864) and catalogued as the 1774th entry in his list. As of 2015, the magnitude 10.5 K-type companion star was located at an angular separation of 18.10 arc seconds along a position angle of 135° from the brighter primary.[5] They appear to be gravitationally bound with an estimated orbital period of around 7,000 years and a linear projected separation of 444.6 AU.[21]
The primary, component A, is a Sun-like star[12] with a stellar classification of F8 V,[6] indicating it is an F-type main-sequence star that is generating energy via hydrogen fusion at its core. It is slightly larger and more massive than the Sun[12][11] and appears mildly variable.[23] The star is radiating 1.5[12] times the Sun's luminosity from its photosphere at an effective temperature of 6,149 K.[13]
HD 119124 A displays a strong infrared excess at a wavelength of 70 μm, indicating an orbiting circumstellar disk of cold dust. The emission fits a model with a grain temperature of 40 K, indicating a minimum orbital radius of 60 AU from the host star. The estimated grain lifetimes are 84,000 years – much shorter than the star's lifespan. This suggests the grains are being replenished via collisions between some number of larger bodies totalling around 1−6 times the mass of the Moon.[12]
This system is a likely (80.4% chance) source of the strong X-ray emission coming from these coordinates.[24]
References
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