Astronomy:Psi2 Lupi

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Short description: Star in the constellation Lupus


Psi2 Lupi
Observation data
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[1] mas
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]

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 2.4 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement 15: 459, doi:10.1086/190168, Bibcode1968ApJS...15..459G. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 Molenda-Zakowicz, J.; Polubek, G. (December 2005), "New beta Cephei and SPB Stars Discovered in Hipparcos Photometry", Acta Astronomica 55: 375–388, Bibcode2005AcA....55..375M. 
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode2012A&A...546A..61D. 
  5. 5.0 5.1 Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I. et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics 424 (2): 727–732, doi:10.1051/0004-6361:20041213, Bibcode2004A&A...424..727P. 
  6. "psi02 Lup". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=psi02+Lup. 
  7. 7.0 7.1 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  8. Chen, Christine H. et al. (September 2012), "A Spitzer MIPS Study of 2.5-2.0 M Stars in Scorpius–Centaurus", The Astrophysical Journal 756 (2): 24, doi:10.1088/0004-637X/756/2/133, 133, Bibcode2012ApJ...756..133C.