KT Lupi

This article is about d Lupi. Not to be confused with δ Lupi.
KT Lupi

A light curve for KT Lupi, plotted from Hipparcos data [1]
Observation data
Epoch J2000      Equinox J2000
Constellation Lupus
Right ascension 15h 35m 53.24806s[2]
Declination −44° 57′ 30.1982″[2]
Apparent magnitude (V) 4.55[3] (4.66 + 6.62)[4]
Characteristics
Spectral type B3 V + B6 V[5]
B−V color index −0.175±0.003[3]
Variable type Be[6]
Astrometry
Radial velocity (Rv)+6.5±2.8[7] km/s
Proper motion (μ) RA: −20.53[2] mas/yr
Dec.: −21.23[2] mas/yr
Parallax (π)7.62 ± 0.43 mas[2]
Distance430 ± 20 ly
(131 ± 7 pc)
Absolute magnitude (MV)−1.03[3]
Details
KT Lup A
Mass5.9±0.1[8] M☉
Radius3.00±0.06[9] R☉
Luminosity794+791
−396[10] L☉
Surface gravity (log g)3.50±0.04[9] cgs
Temperature18,400±184[9] K
Rotational velocity (v sin i)30±0.6[9] km/s
Age21.0±10.6[8] Myr
KT Lup B
Mass2.79[11] M☉
Other designations
d Lup, KT Lup, CD−44°10239, HD 138769, HIP 76371, HR 5781, SAO 225950, WDS J15359-4457AB[12]
Database references
SIMBADdata

KT Lupi is a visual binary star[5] system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.55.[3] As of 1983, the pair had an angular separation of 2.19″±0.03″.[10] Based upon an annual parallax shift of 7.6 mas[2] as seen from Earth's orbit, it is located 430 light-years from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of +6.5 km/s.[7] It is a member of the Lower Centaurus–Crux sub-group of the Scorpius–Centaurus association.[5]

The primary, component A, is a variable Be star,[6] with the variation being modulated by rotation.[13] It is visual magnitude 4.66[4] with a stellar classification of B3 V,[5] matching a B-type main-sequence star. Hiltner et al. (1969) gave a class of B3 IVp,[14] which is still used in some studies.[8][9][10] It is a helium-weak chemically peculiar star showing an enhanced silicon patch near the equator and a silicon-weak region close to the pole.[10] The star is about 21 million years old with nearly six[8] times the mass of the Sun and three times the Sun's radius.[9] It is radiating roughly 794[10] times the Sun's luminosity from its photosphere at an effective temperature of 18,400 K.[9]

The secondary companion, component B, is of magnitude 6.62[4] with a class of B6 V.[5] It has 2.79 times the Sun's mass.[11]

  1. ^ Cite error: The named reference HipDataAccess was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference Chen2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  8. ^ a b c d Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  9. ^ a b c d e f g Cite error: The named reference Arcos2018 was invoked but never defined (see the help page).
  10. ^ a b c d e Cite error: The named reference Briquet2007 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Kouwenhoven2007 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Briquet2004 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Hiltner1969 was invoked but never defined (see the help page).