Lambda Pavonis

Lambda Pavonis
Location of λ Pavonis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pavo
Right ascension 18h 52m 13.03427s[1]
Declination −62° 11′ 15.3324″[1]
Apparent magnitude (V) 4.22[2] (4.00 - 4.26)[3]
Characteristics
Spectral type B2Ve[4] or B2II–IIIe[5]
U−B color index −0.88[6]
B−V color index −0.15[2]
Variable type γ Cas[3]
Astrometry
Radial velocity (Rv)+9.0±4.1[7] km/s
Proper motion (μ) RA: −1.86[1] mas/yr
Dec.: −13.02[1] mas/yr
Parallax (π)2.28 ± 0.18 mas[1]
Distance1,400 ± 100 ly
(440 ± 30 pc)
Absolute magnitude (MV)−3.97[2]
Details
Mass12.5[8] M☉
Radius9±1[9] (polar) R☉
Luminosity8,450[2] L☉
Temperature20,300[10] K
Rotational velocity (v sin i)190[11] km/s
Other designations
λ Pav, CD−62°1254, FK5 704, GC 25823, HD 173948, HIP 92609, HR 7074, SAO 254393, CCDM J18522-6212A, WDS J18522-6211[12]
Database references
SIMBADdata

λ Pavonis, Latinized as Lambda Pavonis, is a single,[13] variable star in the southern constellation of Pavo. It is a blue-white hued star that is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.22.[2] This object is located approximately 1,400 light years from the Sun, based upon parallax. It is a member of the Scorpius–Centaurus association.[14]

A light curve for Lambda Pavonis, plotted from TESS data[15]

This is a massive Be star, a rapidly rotating hot blue star which has developed a gas disk around it. It is a γ Cassiopeiae variable or shell star which has occasionally brightened to magnitude 4.0.[3] The stellar classification of B2Ve[4] suggests it is a B-type main-sequence star that is generating energy through core hydrogen fusion. This star is spinning rapidly with a projected rotational velocity of 190 km/s.[11] This is giving the star an oblate shape with an equatorial bulge that is an estimated 10% larger than the polar radius.[16] Lambda Pavonis has 12.5[8] times the mass of the Sun and nine times the Sun's polar radius.[9] It is radiating 8,450[2] times the luminosity of the Sun from its photosphere at an effective temperature of 20,300 K.[10]

Variations in signals coming from Lambda Pavonis have led to a debate on whether it is a binary, single or pulsating variable star.[14]

  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 e f Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference levenhagen2006 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference MermiliodUBV was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Vieira2017 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Glebocki2005 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 Eggleton2008 was invoked but never defined (see the help page).
  14. ^ a b Cite error: The named reference Levenhagen11 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference belle2012 was invoked but never defined (see the help page).