31 Vulpeculae
Template:Location mark Location of 31 Vulpeculae (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vulpecula |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 4.56[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | G7IIIa Fe-1 Ba[2] |
| U−B Template:Engvar | +0.46[4] |
| B−V Template:Engvar | +0.82[4] |
| Variable type | suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | +2.25[6] km/s |
| Proper motion (μ) | RA: −70.902[1] mas/yr Dec.: −56.360[1] mas/yr |
| Parallax (π) | 14.2796±0.1864 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 0.77[7] |
| Orbit[8] | |
| Period (P) | Script error: No such module "val". |
| Semi-major axis (a) | ≥ Script error: No such module "val". |
| Eccentricity (e) | Script error: No such module "val". |
| Periastron epoch (T) | Script error: No such module "val". |
| Argument of periastron (ω) (secondary) | Script error: No such module "val".° |
| Semi-amplitude (K1) (primary) | Script error: No such module "val". km/s |
| Details[9] | |
| 31 Vul A | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Radius | Script error: No such module "val". Template:Solar radius |
| Luminosity | 52.53[2] Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val". cgs |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | Script error: No such module "val". dex |
| Rotational velocity (v sin i) | Script error: No such module "val".[8] km/s |
| Age | Script error: No such module "val". Myr |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[10] | |
| Database references | |
| SIMBAD | data |
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31 Vulpeculae is a binary star[8] system in the northern constellation of Vulpecula. It is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 4.56.[2] The system is located approximately 228 light years away from the Sun based on parallax,[1] and it is drifting further away with a radial velocity of +2.25 km/s.[6]
The variable radial velocity of this system was first suspected by German Astronomer Friedrich Küstner in 1914. The system appears as a single-lined spectroscopic binary with an orbital period of Script error: No such module "convert". and an eccentricity of 0.38. The a sin i value for the primary is Script error: No such module "convert".,[8] where a is the semimajor axis and i is the (unknown) orbital inclination. This value provides a lower bound on the actual semimajor axis for the orbit.
The primary component is an aging giant star with a stellar classification of G7IIIa Fe-1 Ba,[2] indicating a mild barium star with an underabundance of iron.[8] Having exhausted the supply of hydrogen at its core, it has expanded to eight times the Sun's radius.[9] It is a red clump giant,[3] which indicates it is on the horizontal branch and is generating energy through helium fusion at its core. This is a suspected variable star with a magnitude that varies from 3.77 to 4.08 in the I passband.[5] It is about 700 million years old with 2.4 times the mass of the Sun. The star is radiating 53[2] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,261 K.[9] The companion may be a degenerate white dwarf with about Script error: No such module "val"..[8]
References
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- ↑ a b c d e f Template:Cite DR2
- ↑ a b c d e f Script error: No such module "Citation/CS1". Vizier catalog entry
- ↑ a b Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".Vizier catalog entry
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1". Vizier catalog entry
- ↑ a b c d e f Script error: No such module "Citation/CS1".
- ↑ a b c Script error: No such module "Citation/CS1".
- ↑ Template:Cite simbad
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