HR 4177, also called t² Carinae (t² Car), is a double star[2] in the southern constellation of Carina. It is faintly visible to the naked eye with a combined apparent visual magnitude of +4.77.[2] The two components are HD 92397 and HD 92398. The primary component is located at a distance of approximately 1,600 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +11 km/s.[3] It has a peculiar velocity of 24.3+9.9
−16.1 km/s and may be a runaway star.[4] The star is a member of the BH 99 cluster.[7]
Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Carina |
Right ascension | 10h 38m 44.99524s[1] |
Declination | −59° 10′ 58.7927″[1] |
Apparent magnitude (V) | 4.77 (4.85 + 7.67)[2] |
Characteristics | |
A | |
Spectral type | K4.5Ib-II[3] |
B−V color index | 1.562±0.015[3] |
B | |
Spectral type | B9II/III[3] |
B−V color index | 0.100±0.020[3] |
Astrometry | |
A | |
Radial velocity (Rv) | +11.0±0.8[3] km/s |
Proper motion (μ) | RA: −14.284±0.338[1] mas/yr Dec.: +1.117±0.329[1] mas/yr |
Parallax (π) | 2.0056 ± 0.1809 mas[1] |
Distance | 1,600 ± 100 ly (500 ± 40 pc) |
Absolute magnitude (MV) | −3.66[3] |
B | |
Proper motion (μ) | RA: −14.380±0.089[1] mas/yr Dec.: +0.932±0.085[1] mas/yr |
Parallax (π) | 2.1854 ± 0.0512 mas[1] |
Distance | 1,490 ± 30 ly (460 ± 10 pc) |
Details | |
A | |
Mass | 11.9±0.2[4] M☉ |
Radius | 202+5 −6[1] R☉ |
Luminosity | 8,478±875[1] L☉ |
Temperature | 3,900+63 −48[1] K |
Age | 16.4±1.0[4] Myr |
B | |
Temperature | 8,316+1,256 −1,389[1] K |
Other designations | |
A: GC 14647, HD 92397, HIP 52102, SAO 238295[5] | |
B: GC 14649, HD 92398, HIP 52106, SAO 238297[6] | |
Database references | |
SIMBAD | A |
B |
The magnitude 4.85[2] primary, component A, is a massive K-type supergiant or bright giant with a stellar classification of K4.5Ib-II.[3] Houk (1978) instead listed it with a class of K4/5III: but with some uncertainty about the classification.[8] It has 12[4] times the mass of the Sun and has expanded to 202[1] times the Sun's radius. The star is radiating 8,478[1] times the luminosity of the Sun from its bloated photosphere at an effective temperature of 3,900 K.[1]
The magnitude 7.48 companion star, component B, was discovered by J. Dunlop in 1829. As of 2015, it was located at an angular separation of 14.60″ along a position angle of 21°, relative to the primary.[9] It is a B-type giant/bright giant star with a class of B9II/III.[3] The pair show a common proper motion and roughly similar parallax measurements,[1] but it remains unclear whether they form a gravitationally-bound pair.[2]
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