Lambda Columbae
Variable star in the constellation Columba
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Lambda Columbae, Latinized from λ Columbae, is a probable binary star[12] in the southern constellation of Columba. With an apparent visual magnitude of 4.86,[2] it is faintly visible to the naked eye. The measured annual parallax shift of 9.75 mas[1] yields an estimated distance of roughly 335 light years.
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Columba |
| Right ascension | 05h 53m 06.88101s[1] |
| Declination | −33° 48′ 04.9079″[1] |
| Apparent magnitude (V) | 4.86[2] |
| Characteristics | |
| Spectral type | B5 V[3] |
| U−B color index | −0.57[2] |
| B−V color index | −0.15[2] |
| Variable type | Suspected rotating ellipsoidal[4] |
| Astrometry | |
| Radial velocity (Rv) | +30.0[5] km/s |
| Proper motion (μ) | RA: −4.72[1] mas/yr Dec.: +31.32[1] mas/yr |
| Parallax (π) | 9.75±0.21 mas[1] |
| Distance | 335 ± 7 ly (103 ± 2 pc) |
| Absolute magnitude (MV) | −0.17[6] |
| Details | |
| Mass | 4.0±0.1[3] M☉ |
| Radius | 3.4[7] R☉ |
| Luminosity | 213[8] L☉ |
| Surface gravity (log g) | 4.22[9] cgs |
| Temperature | 13,524[8] K |
| Metallicity [Fe/H] | −0.06[9] dex |
| Rotational velocity (v sin i) | 88[10] km/s |
| Age | 56.6±26.1[3] Myr |
| Other designations | |
| λ Col, CD−33°2599, HD 39764, HIP 27810, HR 2056, SAO 196276.[11] | |
| Database references | |
| SIMBAD | data |
Lambda Columbae has a stellar classification of B5 V,[3] indicating that it is a B-type main sequence star. It is a suspected rotating ellipsoidal variable[14] with a period of 0.64 days and an amplitude of 0.07 magnitude.[15] Confirmation would indicate that this is a close binary system.[4] It has an estimated age of around 57 million years.[3]
In Chinese, 子 (Zǐ), meaning Son, refers to an asterism consisting of λ Columbae and β Columbae.[16] Consequently, λ Columbae itself is known as 子一 (Zǐ yī, English: the First Star of Son).[17] From this Chinese name, the name Tsze is derived.[18]