31 Camelopardalis
Binary star system in the constellation Camelopardalis
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31 Camelopardalis is a binary star system in the northern circumpolar constellation of Camelopardalis. It is visible to the naked eye as a dim point of light with a peak apparent visual magnitude of +5.12.[7] Parallax measurements provide a distance estimate of approximately 460 light years away from the Sun,[2] and the system is drifting closer to the Earth with a radial velocity of −3 km/s.[8]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 05h 54m 57.82481s[2] |
| Declination | +59° 53′ 18.1314″[2] |
| Apparent magnitude (V) | 5.20[3] |
| Characteristics | |
| Spectral type | A2V[4] (A0IV + F0)[5] |
| U−B color index | +0.03[6] |
| B−V color index | +0.010[3] |
| Variable type | β Lyr[7] |
| Astrometry | |
| Radial velocity (Rv) | −2.9±0.9[8] km/s |
| Proper motion (μ) | RA: +1.488[2] mas/yr Dec.: −17.928[2] mas/yr |
| Parallax (π) | 7.1562±0.2336 mas[2] |
| Distance | 460 ± 10 ly (140 ± 5 pc) |
| Orbit[9] | |
| Period (P) | 2.9333 d |
| Eccentricity (e) | 0.00 |
| Longitude of the node (Ω) | 0.00° |
| Periastron epoch (T) | 2,423,443.05±10.00 JD |
| Semi-amplitude (K1) (primary) | 78.0 km/s |
| Details | |
| 31 Cam A | |
| Mass | 3.03±0.08[10] M☉ |
| Luminosity | 179.8+31.7 −26.9 L☉ |
| Temperature | 9,183+149 −147 K |
| Rotational velocity (v sin i) | 75[10] km/s |
| Other designations | |
| 31 Cam, TU Cam, BD+59°920, FK5 2446, GC 7402, HD 214993, HIP 27971, HR 2027, SAO 25447[4] | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary in a circular orbit with an orbital period of 2.93 days.[9] It is a detached binary with two main sequence components that do not fill their Roche lobes.
Joel Stebbins observed the star for more than thirty nights from 1924 through 1927, and discovered that it is a variable star.[11] It was given its variable star designation, TU Cameleopardis, in 1936.[12] The orbital plane is oriented near the line of sight from the Earth, making this a Beta Lyrae–type eclipsing binary variable star. The primary eclipse lowers the visual magnitude to 5.29, while the secondary eclipse lowers it to 5.22.[7]