Nu Telescopii
High proper motion star
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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] meaning it is faintly visible to the naked eye. The object is relatively close to Earth, at a distance of 169 light years, and is approaching the Solar System with a heliocentric radial velocity of about −12 km/s.[5]
 | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 19h 48m 01.1977s[1] |
| Declination | −56° 21′ 45.397″[1] |
| Apparent magnitude (V) | 5.33±0.01[2] |
| Characteristics | |
| Evolutionary stage | main sequence[1] |
| 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 | |
| ν Tel, 67 G. Telescopii, CPD−56°9290, FK5 739, HD 186543, HIP 97421, HR 7510, SAO 246271[12][13] | |
| Database references | |
| SIMBAD | data |
Astronomers disagree about 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 subsequently 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 its 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] Its radius is 1.94 times that 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 which, when viewed, has a white hue. Nu Telescopii's metallicity is around that of the sun.[11] Its motion in space matches that of the IC 2391 cluster, making it a probable member.[17]
Nu Telescopii has 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]