Lambda Columbae

Lambda Columbae, Latinized from λ Columbae, is a probable binary star^[13] in the southern constellation of Columba. With an apparent visual magnitude of 4.86,^[3] it is faintly visible to the naked eye. The measured annual parallax shift of 9.75 mas^[2] yields an estimated distance of roughly 335 light years.

λ Columbae

A light curve for Lambda Columbae, plotted from TESS data.[1] The 0.64 day period is marked in red.
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Columba
Right ascension	05h 53m 06.88101s[2]
Declination	−33° 48′ 04.9079″[2]
Apparent magnitude (V)	4.86[3]
Characteristics
Spectral type	B5 V[4]
U−B color index	−0.57[3]
B−V color index	−0.15[3]
Variable type	Suspected rotating ellipsoidal[5]
Astrometry
Radial velocity (Rv)	+30.0[6] km/s
Proper motion (μ)	RA: −4.72[2] mas/yr Dec.: +31.32[2] mas/yr
Parallax (π)	9.75±0.21 mas[2]
Distance	335 ± 7 ly (103 ± 2 pc)
Absolute magnitude (MV)	−0.17[7]
Details
Mass	4.0±0.1[4] M☉
Radius	3.4[8] R☉
Luminosity	213[9] L☉
Surface gravity (log g)	4.22[10] cgs
Temperature	13,524[9] K
Metallicity [Fe/H]	−0.06[10] dex
Rotational velocity (v sin i)	88[11] km/s
Age	56.6±26.1[4] Myr
Other designations
λ Col, CD−33°2599, HD 39764, HIP 27810, HR 2056, SAO 196276.[12]
Database references
SIMBAD	data

Lambda Columbae has a stellar classification of B5 V,^[4] 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.^[5] It has an estimated age of around 57 million years.^[4]

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]