Lambda Crucis

λ Crucis
Location of λ Crucis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Crux
Right ascension 12h 54m 39.18258s[1]
Declination −59° 08′ 48.1229″[1]
Apparent magnitude (V) 4.62[2]
Characteristics
Evolutionary stage main sequence
Spectral type B4 Vne[3]
U−B color index −0.60[4]
B−V color index −0.15[4]
Variable type β Cep?[2]
Astrometry
Radial velocity (Rv)+12.0±4.2[5] km/s
Proper motion (μ) RA: −32.92[1] mas/yr
Dec.: −14.60[1] mas/yr
Parallax (π)8.50 ± 0.21 mas[1]
Distance384 ± 9 ly
(118 ± 3 pc)
Absolute magnitude (MV)−1.2[6]
Details
Mass5.0±0.1[7] M☉
Radius3.00[8] R☉
Luminosity790[6] L☉
Surface gravity (log g)3.01[8] cgs
Temperature16,500[8] K
Rotational velocity (v sin i)290[8] km/s
Age53.3±8.1[7] Myr
Other designations
λ Cru, Lambda Cru, CD−58°4794, HD 112078, HIP 63007, HR 4897, SAO 240368[9]
Database references
SIMBADdata

λ Crucis, Latinized as Lambda Crucis, is a single,[10] variable star in the southern constellation Crux, near the constellation border with Centaurus. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude that fluctuates around 4.62.[2] The star is located approximately 384 light-years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s.[5] It is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.[6]

A light curve for Lambda Crucis, plotted from Hipparcos data[11]

λ Crucis is listed in the General Catalogue of Variable Stars as a possible β Cephei-type variable. Its brightness varies with an amplitude of 0m.02 over a period of 0.3951 days.[2] However, it is currently thought more likely to be a different type of variable,[12] possibly a λ Eridani variable or rotating ellipsoidal variable.[13][14]

This object is a B-type main-sequence star with a stellar classification of B4 Vne,[3] where the suffix notation indicates "nebulous" (broad) lines due to rapid rotation, along with emission lines from circumstellar material, making it a Be star.[13] It is around 53[7] million years old and is spinning rapidly with a projected rotational velocity of 341 km/s.[15] The star has five[7] times the mass of the Sun and about 3.0[8] times the Sun's radius. It is radiating 790[6] times the luminosity of the Sun from its photosphere at an effective temperature of 16,500 K.[8]

  1. ^ a b c d e 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 Samus2017 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Levenhagen2006 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference clpl4 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference rgcrv66 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference aaa216_1_44 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference mnras410_1_190 was invoked but never defined (see the help page).
  8. ^ a b c d e f Cite error: The named reference arcos was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Rizzuto2013 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference HIPCurve was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference stankov was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference balona was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference morris was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference uesugi_fukuda70 was invoked but never defined (see the help page).