HR 4177
Star in the constellation Carina
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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.[5] The star is a member of the BH 99 cluster.[8]
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| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| 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: −14.208±0.036[4] mas/yr Dec.: 0.968±0.030[4] mas/yr |
| Parallax (π) | 2.2858±0.0334 mas[4] |
| Distance | 1,430 ± 20 ly (437 ± 6 pc) |
| Details | |
| A | |
| Mass | 11.9±0.2[5] 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[5] Myr |
| B | |
| Mass | 3.46±0.61[4] M☉ |
| Radius | 3.42+1.01 −0.11[4] R☉ |
| Luminosity | 1,991+800 −600[4] L☉ |
| Surface gravity (log g) | 3.94+0.90 −0.67[4] cgs |
| Temperature | 12,267+736 −101[4] K |
| Metallicity [Fe/H] | 0.77+0.73 −0.31[4] dex |
| Other designations | |
| t2 Car, CPD−58°2460, HR 4177, CCDM J10388-5911, WDS J10387-5911[6] | |
| A: GC 14647, HD 92397, HIP 52102, SAO 238295[6] | |
| B: GC 14649, HD 92398, HIP 52106, SAO 238297[7] | |
| 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.[9] It has 12[5] 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.[10] 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]