Eta Lupi

η Lupi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension 16h 00m 07.32786s[1]
Declination −38° 23′ 48.1513″[1]
Apparent magnitude (V) 3.41[2] (3.37 + 7.50 + 10.85)[3]
Characteristics
Spectral type B2 IV + A5 Vp + F5 V[4]
U−B color index −0.83[2]
B−V color index −0.22[2]
Astrometry
Radial velocity (Rv)+1.00±3.80[5] km/s
Proper motion (μ) RA: −16.96[1] mas/yr
Dec.: −27.83[1] mas/yr
Parallax (π)7.38 ± 0.18 mas[1]
Distance440 ± 10 ly
(136 ± 3 pc)
Absolute magnitude (MV)−2.24[6]
Details
η Lup A
Mass7.0±0.2[7] M☉
Radius6.7[8] R☉
Luminosity1,729[9] L☉
Temperature14,668[9] K
Rotational velocity (v sin i)242[10] km/s
Age39.8±9.2[7] Myr
Other designations
η Lup, CD−38° 10797, HD 143118, HIP 78384, HR 5948, SAO 207208.[11]
Database references
SIMBADdata

η Lupi, often Latinised as Eta Lupi, is a probable triple star[4][12] system in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.41.[2] Based upon an annual parallax shift of 27.80[1] mas as seen from Earth, it is located around 136 parsecs (440 ly) distant from the Sun. It is a member of the Upper Centaurus–Lupus subgroup of the nearby Sco OB2 association.[13]

The inner pair in this triple system has an estimated orbital period of around 27,000 years.[12] As of 2013, they had an angular separation of 15.0 arc seconds along a position angle of 19°.[3] The primary star, component A, is an evolving A-type subgiant star with a stellar classification of B2 IV.[4] It has used up the supply of hydrogen at its core and has begun to expand off the main-sequence.

The secondary, component B, is a chemically peculiar A-type main sequence star with a class of A5 Vp[4] and an estimated mass 2.10 times that of the Sun.[12] The outer member, component C, has an orbital period of around half a million years.[12] As of 2007, it had an angular separation of 115.8 arc seconds along a position angle of 248° from the primary.[3] It is an F-type main sequence star with a classification of F5 V and an estimated 1.29 times the Sun's mass.[12]

  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 Nicolet1978 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference uesugi_fukuda70 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ a b c d e Cite error: The named reference Tokovinin2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Kouwenhoven2007 was invoked but never defined (see the help page).