HD 47500, also known as HR 2446, is a binary star[15] in the southern constellation Columba. The primary has an apparent magnitude of 5.91,[1] making it faintly visible to the naked eye if viewed under ideal conditions. As for the companion, its visual magnitude is 7.51.[1] The system is located relatively far at a distance of 1,120 light years based on parallax measurements,[6] and is receding with a heliocentric radial velocity of 21 km/s.[5]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Columba |
A | |
Right ascension | 06h 37m 13.84s[1] |
Declination | −36° 59′ 26.37″[1] |
Apparent magnitude (V) | 5.91±0.01[1] |
B | |
Right ascension | 06h 37m 13.84s[1] |
Declination | −36° 59′ 25.91″[1] |
Apparent magnitude (V) | 7.51±0.01[1] |
Characteristics | |
A | |
Evolutionary stage | main sequence[2] |
Spectral type | B6 IV-V[3] |
U−B color index | −0.52[4] |
B−V color index | −0.12[4] |
Astrometry | |
Radial velocity (Rv) | 21±4[5] km/s |
Proper motion (μ) | RA: −9.053 mas/yr[6] Dec.: +11.625 mas/yr[6] |
Parallax (π) | 2.9218 ± 0.2076 mas[6] |
Distance | 1,120 ± 80 ly (340 ± 20 pc) |
Absolute magnitude (MV) | −1.93[7] |
Details | |
A | |
Mass | 5.01±0.05[8] M☉ |
Radius | 7.33[9] R☉ |
Luminosity | 1,482+665 −459[2] L☉ |
Surface gravity (log g) | 3.61[10] cgs |
Temperature | 14,703±290[11] K |
Metallicity [Fe/H] | −0.07[10] dex |
Rotational velocity (v sin i) | 36[12] km/s |
Age | 34±1[2] Myr |
Other designations | |
Database references | |
SIMBAD | The system |
A | |
B |
The binary nature of this system was first discovered by Richard Alfred Rossiter in 1942.[16] Their current separation is half of an arcsecond, making it difficult to measure the components properties. Nevertheless, the secondary component is located along a position angle of 4° as of 1999.[17]
HD 47500 has a stellar classification of B6 IV-V,[3] a B-type star with a luminosity class intermediate between a subgiant and main sequence star. Hube (1970) gave the primary a slightly cooler class of B7 III,[18] indicating that it is already a giant star, while Houk (1982) gave it a class of B5/7 IV,[19] intermediate between a B5 and B7 subgiant. Nevertheless, it is estimated to be 34 million years old, having completed 98.5% of its main sequence lifetime.[2] HD 47500 A has 5.01 times the mass of the Sun[8] and an enlarged radius of 7.33 R☉.[9] It radiates 1,482 times the luminosity of the Sun.[2] from its photosphere at an effective temperature of 14,703 K,[11] giving it a bluish-white hue. Unlike most hot stars, the object spins modestly with a projected rotational velocity of 36 km/s.[12]