Nu Telescopii, Latinized from ν Telescopii, is a slightly evolved star in the southern constellation Telescopium. It has an apparent visual magnitude of 5.33,[4] allowing it to be faintly visible to the naked eye. The object is relatively close at a distance of 169 light years but is approaching the Solar System with a heliocentric radial velocity of about −12 km/s.[5]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Telescopium |
Right ascension | 19h 48m 01.1977s[1] |
Declination | −56° 21′ 45.3996″[1] |
Apparent magnitude (V) | 5.33±0.01[2] |
Characteristics | |
Spectral type | A7 III/IV[3] |
B−V color index | +0.20[4] |
Astrometry | |
Radial velocity (Rv) | −12.4±4.2[5] km/s |
Proper motion (μ) | RA: +90.983 mas/yr[1] Dec.: −137.406 mas/yr[1] |
Parallax (π) | 19.3152 ± 0.0783 mas[1] |
Distance | 168.9 ± 0.7 ly (51.8 ± 0.2 pc) |
Absolute magnitude (MV) | +1.86[6] |
Details | |
Mass | 1.85[7] M☉ |
Radius | 1.94±0.09[8] R☉ |
Luminosity | 15.6±0.1[9] L☉ |
Surface gravity (log g) | 4.08+0.08 −0.07[10] cgs |
Temperature | 8,199±279[7] K |
Metallicity [Fe/H] | −0.02[11] dex |
Age | 686[7] Myr |
Other designations | |
Database references | |
SIMBAD | data |
There hasn't been much agreement on Nu Telescopii's spectral classification. It was initially categorized as Am star, with a classification of kA4mF3IV:[14] . This indicates that the object has the calcium K-lines of an A4 star and the metallic lines of a F3 subgiant. However, Nu Telescopii was shown not to have a peculiar spectrum and was given a class of A9 Vn,[15] indicating that it is an A-type main-sequence star displaying broad (nebulous) absorption lines due to rapid rotation. It has since been classified as an evolved A7 star with either a blended luminosity class of a giant star or subgiant (III/IV)[3] or only subgiant (IV).[16]
Nu Telescopii has a mass of 1.85 M☉ and an age of 686 million years.[7] It has 1.94 times the radius of the Sun[8] and has an effective temperature of 8,199 K.[7] These parameters yield a luminosity of 15.6 L☉[9] from its photosphere and when viewed, has a white hue. Nu Telescopii's metallicity – what astronomers dub as elements heavier than helium – is around solar level.[11] Its motion in space matches that of the IC 2391 cluster, making it a probable member. [17]
There is a faint magnitude 9.3 companion star at an angular separation of 102 arc seconds along a position angle of 333°, as of 2010.[18]
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