Psi2 Lupi

Psi2 Lupi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension 15h 42m 41.02206s[1]
Declination −34° 42′ 37.4617″[1]
Apparent magnitude (V) 4.75[2]
Characteristics
Spectral type B5 V[3]
U−B color index −0.570[2]
B−V color index −0.146[2]
Variable type Microvariable[3]
Astrometry
Radial velocity (Rv)+3.9±2.8[4] km/s
Proper motion (μ) RA: −21.37[1] mas/yr
Dec.: −29.98[1] mas/yr
Parallax (π)8.97 ± 0.27 mas[1]
Distance360 ± 10 ly
(111 ± 3 pc)
Absolute magnitude (MV)−1.44[2]
Orbit[5]
Period (P)12.26 d
Eccentricity (e)0.19
Periastron epoch (T)2438252.97 ± 10.0 JD
Argument of periastron (ω)
(secondary)		82.8°
Semi-amplitude (K1)
(primary)		63.3 km/s
Semi-amplitude (K2)
(secondary)		66.4 km/s
Details
Surface gravity (log g)4.29[3] cgs
Temperature15,135[3] K
Other designations
ψ2 Lup, 4 Lup, CD−34° 10494, HD 140008, HIP 76945, HR 5839, SAO 206889.[6]
Database references
SIMBADdata

Psi2 Lupi (ψ2 Lup) is a triple star[7] system in the constellation Lupus. It is visible to the naked eye with an apparent magnitude of 4.75.[2] Based upon an annual parallax shift of 8.97[1] mas as seen from Earth, it is located around 360 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.016±0.009 due to interstellar dust. This system is a member of the Upper Centaurus–Lupus subgroup of the Scorpius–Centaurus association.[8]

The inner pair of stars in this system form a double-lined spectroscopic binary with an orbital period of 12.26 days and an eccentricity of 0.19. The two components are described as similar in appearance.[5] They have the spectrum of a B-type main sequence star with a stellar classification of B5 V.[3] The luminosity has a micro-variability with a frequency of 0.94483 cycles per day and an amplitude of 0.0067 in magnitude.[3] The third component is a magnitude 10 star at an angular separation of 0.51 arc seconds.[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 e Cite error: The named reference GutierrezMoreno1968 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference MolendaZakowicz2005 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Chen2012 was invoked but never defined (see the help page).