Lambda Draconis

λ Draconis
Location of λ Draconis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Draco
Right ascension 11h 31m 24.22075s[1]
Declination +69° 19′ 51.8696″[1]
Apparent magnitude (V) +3.85[2]
Characteristics
Evolutionary stage asymptotic giant branch[3]
Spectral type M0III-IIIa Ca1[4]
U−B color index +1.97[2]
B−V color index +1.62[2]
Variable type slow irregular[5]
Astrometry
Radial velocity (Rv)+6.58±0.30[6] km/s
Proper motion (μ) RA: −40.97[1] mas/yr
Dec.: −19.19[1] mas/yr
Parallax (π)9.79 ± 0.15 mas[1]
Distance333 ± 5 ly
(102 ± 2 pc)
Absolute magnitude (MV)−1.14±0.033[7]
Details[8]
Mass1.53±0.12 M☉
Radius69.99+1.06
−1.10 R☉
Luminosity884±52 L☉
Surface gravity (log g)1.10±0.05[9] cgs
Temperature3,761±47 K
Metallicity [Fe/H]0.00 dex
Age2.33±0.48 Gyr
Other designations
λ Dra, 1 Draconis, BD−70° 665, FK5 433, HD 100029, HIP 56211, HR 4434, SAO 15532[10]
Database references
SIMBADdata

Lambda Draconis (λ Draconis, abbreviated Lam Dra, λ Dra), also named Giausar (/ˈdʒɔːzɑːr/ JAW-zar),[11][12] is a solitary,[13] orange-red[14] star in the northern circumpolar constellation of Draco. It is visible to the naked eye with an apparent visual magnitude of +3.85.[2] Based upon an annual parallax shift of 9.79 mas as seen from the Earth,[1] the star is located around 333 light years from the Sun.

This is an evolved red giant star on the asymptotic giant branch[3] with a stellar classification of M0III-IIIa Ca1.[4] It is a suspected slow irregular variable with a periodicity of roughly 1,100 days.[5] It has an estimated 1.53 times the mass of the Sun and a measured radius of 70 times the radius of the Sun. It is radiating 884 times the solar luminosity from its photosphere at an effective temperature of 3,761 K.[8]

  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 Johnson1966 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference eggen1992 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference perkins1989 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Samus2007 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Famaey2009 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference park2013 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Baines2018 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Tagaki2011 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  12. ^ Cite error: The named reference IAU-LSN 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. ^ Cite error: The named reference Moore2013 was invoked but never defined (see the help page).