171 G. Puppis
Star in the constellation Puppis
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171 G. Puppis (171 Pup) is a triple[13] star system in the constellation of Puppis â the stern of Argo Navis â of apparent magnitude +5.38. Lacking a Bayer designation, it is instead known by its Gould designation. Based upon parallax measurements, the system is 49.6 light years away from the Solar System.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Puppis |
| A | |
| Right ascension | 07h 45m 35.02168s[1] |
| Declination | â34° 10â² 20.5143â³[1] |
| Apparent magnitude (V) | 5.38[2] |
| B | |
| Right ascension | 07h 45m 38.42749s[3] |
| Declination | â33° 55â² 51.3414â³[3] |
| Apparent magnitude (V) | 16.7[4] |
| Characteristics | |
| A | |
| Evolutionary stage | Subgiant[5] |
| Spectral type | F9 V[6] |
| UâB color index | â0.085[2] |
| BâV color index | +0.56[2] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +102.6[7] km/s |
| Proper motion (μ) | RA: â221.54[1] mas/yr Dec.: +1,722.11[1] mas/yr |
| Parallax (Ï) | 65.75±0.51 mas[1] |
| Distance | 49.6 ± 0.4 ly (15.2 ± 0.1 pc) |
| Absolute magnitude (MV) | +4.57[8] |
| Orbit[9] | |
| Primary | Aa |
| Name | Ab |
| Period (P) | 8,406+29 â7 days |
| Semi-major axis (a) | 9.15+0.31 â0.33 AU |
| Eccentricity (e) | 0.443+0.002 â0.001 |
| Argument of periastron (Ï) (secondary) | 184.38+0.16 â0.17° |
| Semi-amplitude (K1) (primary) | 4.762±0.013 km/s |
| Details | |
| Aa | |
| Mass | 0.85[10] Mâ |
| Radius | 1.13+0.10 â0.09[9] Râ |
| Luminosity | 1.80+0.49 â0.28[9] Lâ |
| Surface gravity (log g) | 4.34+0.07 â0.09[9] cgs |
| Temperature | 5,858±70[10] K |
| Metallicity [Fe/H] | â0.78±0.06[10] dex |
| Rotational velocity (v sin i) | 4.4[8] km/s |
| Ab | |
| Mass | â¥0.42±0.03[9] Mâ |
| B | |
| Mass | 0.507±0.007[11] Mâ |
| Radius | 0.0135[11][a] Râ |
| Luminosity | 6.2Ã10â5[11] Lâ |
| Surface gravity (log g) | 7.882±0.008[11] cgs |
| Temperature | 4,405±15[11] K |
| Other designations | |
| GJ 288, HD 63077, HR 3018[12] | |
| A: CDâ33°4113, HIP 37853, HR 3018, SAO 198404 | |
| B: VB 3, WD 0743-336 | |
| Database references | |
| SIMBAD | A |
| B | |
| ARICNS | A |
| B | |
The inner pair form a spectroscopic binary with an orbital period of around 23 years. The orbit has a semi-major axis of 9.15 AU and a mild eccentricity of 0.443.[9] The primary has a spectral class of F9V,[6] matching a late F-type main-sequence star. However, stellar evolution models suggest it has left the main sequence and is now a subgiant.[5][14] Little is known about the secondary, but its mass should be at least 0.42 Mâ.[9]
There is a common proper motion companion, Van Biesbroeck 3 or WD 0743â340, at an angular separation of 869.65â³ along a position angle of 2.81° from the inner pair. This is a white dwarf with a classification of DC11.0 and a temperature of 4,600 K, making it one of the coolest white dwarfs known.[15]
171 G. Puppis is believed to be among the oldest star systems in the solar neighbourhood, being of the Population II. The primary's metal-to-hydrogen ratio is a logarithm of â0.78, translating to 16% of the Sun's abundance.[10] In the early universe, the metallicity of the interstellar medium was much lower than that of the current universe.[16]
Notes
- Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:
