Delta2 Telescopii

For other stars with this Bayer designation, see δ Telescopii.
Delta2 Telescopii
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Telescopium
Right ascension 18h 32m 01.94437s[1]
Declination −45° 45′ 26.5636″[1]
Apparent magnitude (V) 5.05[2]
Characteristics
Spectral type B3 IV/V[3] or B3 III[4]
U−B color index −0.52[2]
B−V color index −0.12[2]
Astrometry
Proper motion (μ) RA: +0.16[1] mas/yr
Dec.: −10.23[1] mas/yr
Parallax (π)2.73 ± 0.26 mas[1]
Distance1,200 ± 100 ly
(370 ± 30 pc)
Absolute magnitude (MV)−1.46[5]
Orbit[6]
Period (P)21.7056 d
Eccentricity (e)0.22
Periastron epoch (T)2,435,216.669 JD
Argument of periastron (ω)
(secondary)		12.7°
Semi-amplitude (K1)
(primary)		34.9 km/s
Details
Mass7.6±0.1[7] M☉
Luminosity (bolometric)5,129[8] L☉
Temperature17,100[8] K
Rotational velocity (v sin i)0[9] or 45[4] km/s
Age39.8±7.6[7] Myr
Other designations
δ2 Tel, CD−45° 12556, HD 170523, HIP 90853, HR 6938, SAO 229095[10]
Database references
SIMBADdata

Delta2 Telescopii is a blue-white-hued binary star[6] system in the southern constellation of Telescopium. It is faintly visible to the naked eye, having an apparent visual magnitude of 5.05.[2] The distance to this system, as determined with an annual parallax shift of 2.73 mas,[1] is roughly 1,200 light-years. At that distance, the visual magnitude of the star is diminished by an extinction of 0.36 due to interstellar dust.[5] The pair have an orbital period of 21.7 days and an eccentricity of 0.22.[6] For the merged stellar classification, Houk (1978) gives B3 IV/V,[3] while Levato (1975) lists a more evolved class of B3 III.[4] It appears to be a relatively young system, barely 40 million years old.[7]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Fernie1983 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference levato was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Pourbaix2009 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference uesugi_fukuda70 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).