  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 06h 19m 59.60059s[1] |
| Declination | −2° 56′ 40.1765″[1] |
| Apparent magnitude (V) | 4.91[2] |
| Characteristics | |
| Evolutionary stage | Asymptotic giant branch[3] |
| Spectral type | M1III[4] |
| U−Bcolor index | +1.96[5] |
| B−Vcolor index | +1.60[5] |
| Astrometry | |
| Radial velocity (Rv) | +48.60[6] km/s |
| Proper motion (μ) | RA: −6.42[1]mas/yr Dec.: −1.26[1]mas/yr |
| Parallax (π) | 7.02±0.23 mas[1] |
| Distance | 460 ± 20 ly (142 ± 5 pc) |
| Absolute magnitude (MV) | −0.86[2] |
| Details | |
| Radius | 55.89+4.05 −4.54[7] R☉ |
| Luminosity | 673±26[7] L☉ |
| Temperature | 3,932+170 −135[7] K |
| Other designations | |
| NSV 2918,BD−02°1564,GC 8137,HD 44131,HIP 30093,HR 2275,SAO 133118[8] | |
| Database references | |
| SIMBAD | data |
HD 44131 is astar in theequatorialconstellation ofOrion, positioned near the eastern constellation border withMonoceros. It has a reddish hue and is faintly visible to the naked eye with anapparent visual magnitude of 4.91.[2] The star is located at a distance of approximately 465 light years from theSun based onparallax,[1] and it is drifting further away with aradial velocity of +48.6 km/s.[6] Based on radial velocity variations, it is a candidatespectroscopic binary system and a preliminary orbital solution was published in 1991 with a period of 9.29 yr. However, these velocity variations may be due to other causes.[9]
This is an agingred giant star currently on theasymptotic giant branch[3] with astellar classification of M1III.[4] With the supply ofcore hydrogen exhausted, this star has cooled and expanded off themain sequence. It is now estimated to have 56 times theradius of the Sun and is radiating 673 times theSun's luminosity from its swollenphotosphere at aneffective temperature of 3,932 K.[7] This is a periodic variable of unknown type with afrequency of 0.11212 cycles per day (period of 8.9 days) and anamplitude of 0.0106 in magnitude.[11]
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