Delta1 Telescopii

For other stars with this Bayer designation, see δ Telescopii.
Delta1 Telescopii
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Telescopium
Right ascension 18h 31m 45.43288s[1]
Declination −45° 54′ 53.3166″[1]
Apparent magnitude (V) 4.94[2]
Characteristics
Spectral type B6 IV[3]
U−B color index −0.438[2]
B−V color index −0.121[2]
Astrometry
Proper motion (μ) RA: −3.75[1] mas/yr
Dec.: −27.43[1] mas/yr
Parallax (π)4.61 ± 0.19 mas[1]
Distance710 ± 30 ly
(217 ± 9 pc)
Absolute magnitude (MV)−0.74[4]
Orbit[5]
Period (P)18.8456 d
Eccentricity (e)0.51
Periastron epoch (T)2435003.693 JD
Argument of periastron (ω)
(secondary)		78°
Semi-amplitude (K1)
(primary)		65.0 km/s
Details
δ1 Tel A
Mass4.52±0.06[3] M☉
Radius4.7[6] R☉
Luminosity899[3] L☉
Temperature12,417[3] K
Rotational velocity (v sin i)11[3] km/s
Age178[4] Myr
Other designations
δ1 Tel, CD−45° 12550, HD 170465, HIP 90830, HR 6934, SAO 229092[7]
Database references
SIMBADdata

Delta1 Telescopii is a blue-white-hued binary star[5] system in the southern constellation of Telescopium. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.94.[2] Based upon an annual parallax shift of 4.61 mas as seen from Earth,[1] this system is roughly 710 light-years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.29 due to interstellar dust.[4]

This system is a single-lined spectroscopic binary with an orbital period of 18.8 days and an eccentricity of 0.51.[5] The estimated size of the semimajor axis has a minimum of 14.5×106 km, with the uncertainty due to lack of a value for the orbital inclination.[8] The primary, component A, has a stellar classification of B6 IV,[3] suggesting it is an evolving B-type subgiant star. Delta1 Telescopii has an estimated 4.5[3] times the mass of the Sun and about 4.7[6] times the Sun's radius. It is radiating 899[3] times the solar luminosity from its photosphere at an effective temperature of 12,417 K.[3]

  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 apjs15 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Pourbaix2009 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Buscombe1962 was invoked but never defined (see the help page).