Lambda Telescopii

λ Telescopii, Latinized as Lambda Telescopii, is a solitary,^[17] bluish-white hued star located in the southern constellation of Telescopium. It has an apparent magnitude of 4.84,^[2] making it readily visible to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 490 light years,^[1] and it is currently approaching the Solar System with a somewhat constrained heliocentric radial velocity of −2 km/s.^[6] At its current distance, the visual magnitude of Lambda Telescopii is diminished by an extinction of 0.25 due to interstellar dust^[18] and it has an absolute magnitude of −1.51.^[7]

λ Telescopii

Location of λ Tel (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Telescopium
Right ascension	18h 58m 27.79251s[1]
Declination	−52° 56′ 19.1999″[1]
Apparent magnitude (V)	4.84±0.01[2]
Characteristics
Spectral type	B9.5 IV/V[3] or B9 III[4]
B−V color index	−0.05[5]
Astrometry
Radial velocity (Rv)	−2±4.2[6] km/s
Proper motion (μ)	RA: +13.365 mas/yr[1] Dec.: −8.805 mas/yr[1]
Parallax (π)	6.6117±0.1718 mas[1]
Distance	490 ± 10 ly (151 ± 4 pc)
Absolute magnitude (MV)	−1.51[7]
Details
Mass	2.81+0.36 −0.38[8] M☉
Radius	5.53±0.28[9] R☉
Luminosity	260+13 −12[1] L☉
Surface gravity (log g)	3.56[10] cgs
Temperature	10,139[11] K
Metallicity [Fe/H]	+0.19[11] dex
Rotational velocity (v sin i)	110[12][13] km/s
Age	268[14] Myr
Other designations
λ Tel, 41 G. Telescopii[15], CPD−53°9402, FK5 708, GC 26016, HD 175510, HIP 93148, HR 7134, SAO 245834[16]
Database references
SIMBAD	data

The object has been given several stellar classifications over the years. Lambda Telescopii has been classified as B9 III (evolved giant star),^[4] A0 V (A-type main-sequence star),^[13] and B9 .5 IV/V.^[3]

The accepted classification for Lambda Telescopii is B9.5 IV/V,^[3] indicating that it is a late B-type star with the blended luminosity class of a subgiant and a main sequence star. Gaia DR3 stellar evolution models place it near the end of its main sequence lifetime.^[1] The star is 268 million years old^[14] with a relatively high rate of spin, showing a projected rotational velocity of 110 km/s.^[12][13] Lambda Telescopii is metal enriched with an iron abundance 155% that of the Sun, or [Fe/H] = +0.19.^[11] The star has 2.81 times the mass of the Sun^[8] and it radiates 260 times the luminosity of the Sun^[1] from its photosphere – which is 5.53 times the size of the Sun's – at an effective temperature of 10,193 K.^{[9] [11]}