HR 3831
A light curve for IM Velorum (HR 3831), plotted from TESS data. The 2.852 day period is shown in red. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela |
| HD 83368A | |
| Right ascension | 09h 36m 25.4255s |
| Declination | −48° 45′ 04.240″ |
| Apparent magnitude (V) | 6.23 |
| HD 83368B | |
| Right ascension | 09h 36m 25.3660s |
| Declination | −48° 45′ 07.505″ |
| Apparent magnitude (V) | 10.31 |
| Characteristics | |
| HD 83368A | |
| Spectral type | A8VSrCrEu |
| Variable type | Rapidly oscillating Ap |
| HD 83368B | |
| Spectral type | F9V |
| Astrometry | |
| HD 83368A | |
| Proper motion (μ) | RA: −8.16±0.03 mas/yr Dec.: −18.85±0.03 mas/yr |
| Parallax (π) | 14.01±0.03 mas |
| Distance | 232.8 ± 0.5 ly (71.4 ± 0.2 pc) |
| HD 83368B | |
| Radial velocity (Rv) | −4.0±0.3 km/s |
| Proper motion (μ) | RA: −9.41±0.19 mas/yr Dec.: −14.00±0.17 mas/yr |
| Parallax (π) | 14.31 ± 0.15 mas |
| Distance | 228 ± 2 ly (69.9 ± 0.7 pc) |
| Details | |
| Aa | |
| Mass | 1.78+0.12 −0.17 M☉ |
| Radius | 2.003 R☉ |
| Luminosity (bolometric) | 12.33 L☉ |
| Surface gravity (log g) | 4.2 cgs |
| Temperature | 7650 K |
| Rotation | 2.851976±0.00003 d |
| Rotational velocity (v sin i) | 33.8±1.0 km/s |
| Age | 0.93+0.42 −0.34 Gyr |
| Ab | |
| Mass | 0.64 M☉ |
| Radius | 0.60 R☉ |
| Temperature | 4,175 K |
| B | |
| Mass | 1 M☉ |
| Other designations | |
| CD−48 4831, HD 83368, HIP 47145, HR 3831, SAO 221339, GSC 08176-00283, IM Vel | |
| HD 83368A: 2MASS J09362541-4845042, TYC 8176-283-1 | |
| HD 83368B: 2MASS J09362537-4845072, Gaia DR2 5410092611662456704, TYC 8176-2818-1 | |
| Database references | |
| SIMBAD | data |
HR 3831, also known as HD 83368, is a triple star system in the southern constellation of Vela at a distance of 233 light years. This object is barely visible to the naked eye as a dim, blue star with an apparent visual magnitude of 6.232. It is approaching the Earth with a heliocentric radial velocity of 4.0±0.3 km/s.
The star system is a hierarchical binary, made up of an inner and an outer pair. The inner pair has an orbital separation of 13 astronomical units, and contain the primary star, HR 3831 Aa, and the secondary HR 3831 Ab. The outer component have a 214 AU projected separation from the inner pair. The primary star, HR 3831 Aa, is a pulsating variable of a rapidly oscillating Ap type. It has a single yet strongly distorted dipole pulsation mode with a frequency of 1427 μHz. The primary star is chemically peculiar, exhibiting spots of enhanced concentrations of lithium, europium and oxygen.
The star's variability was discovered by Pierre Renson, and announced in 1977. It was given its variable star designation, IM Velorum, in 1981.