HD 200044
M-type star in the constellation Delphinus
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HD 200044 (HR 8044) is a solitary[13] star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.7,[3] allowing it to be faintly seen with the naked eye. The object is located 598 light years away,[2] but is approaching the Solar System with a heliocentric radial velocity of −15.07 km/s.[8]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Delphinus[1] |
| Right ascension | 21h 00m 27.6883s[2] |
| Declination | +19° 19′ 46.493″[2] |
| Apparent magnitude (V) | 5.70±0.01[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | M3 IIIab[5] |
| B−V color index | +1.61[6] |
| Variable type | suspected[7] |
| Astrometry | |
| Radial velocity (Rv) | −15.07±0.09[8] km/s |
| Proper motion (μ) | RA: −15.483 mas/yr[2] Dec.: −59.705 mas/yr[2] |
| Parallax (π) | 5.455±0.0753 mas[2] |
| Distance | 598 ± 8 ly (183 ± 3 pc) |
| Absolute magnitude (MV) | −0.33[1] |
| Details | |
| Mass | 1.32[9] M☉ |
| Radius | 58[10] R☉ |
| Luminosity | 507[11] L☉ |
| Surface gravity (log g) | 1.11[12] cgs |
| Temperature | 3,707[10] K |
| Age | 13.5[12] Gyr |
| Other designations | |
| AG+19°2128, BD+18°4675, GC 29329, HD 200044, HIP 103675, HR 8044, SAO 106747, WDS J21005+1920A | |
| Database references | |
| SIMBAD | data |
HD 200044 has a spectral classification of M3 IIIab,[5] indicating that its an ageing red giant. It is currently on the asymptotic giant branch and is fusing hydrogen and helium in shells around an inert carbon core.[4] As a consequence, it has expanded to 58 times the radius of the Sun and is now radiating with a luminosity over 500 times greater than that of the Sun. HD 200044's large size and high luminosity yield an effective temperature of 3,707 K, giving it a red glow. HD 200044 is suspected to be a variable star with an amplitude of 0.05 magnitudes.[7]
There is a 10th magnitude optical companion separated 49.3″ away and at a position angle of 337° as of 2014. It has a much smaller parallax (ie. greater distance) than HD 20044[14] and the separation of the two stars is increasing due to HD 200044's high proper motion.[15]