Lambda2 Tucanae

This article is about Lambda2 Tucanae. For other stars with this Bayer designation, see Lambda Tucanae.
Lambda2 Tucanae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Tucana
Right ascension 00h 55m 00.31129s[1]
Declination −69° 31′ 37.5025″[1]
Apparent magnitude (V) +5.45[2]
Characteristics
Spectral type K2 III[3]
B−V color index +1.10[2]
Astrometry
Radial velocity (Rv)+5.1±2.8[4] km/s
Proper motion (μ) RA: +6.842[1] mas/yr
Dec.: −43.735[1] mas/yr
Parallax (π)14.6214 ± 0.0817 mas[1]
Distance223 ± 1 ly
(68.4 ± 0.4 pc)
Absolute magnitude (MV)+1.29[5]
Details[2]
Mass1.75 M☉
Radius9.84+0.22
−0.42[1] R☉
Luminosity39.2±0.3[1] L☉
Surface gravity (log g)2.74 cgs
Temperature4,605+101
−52[1] K
Metallicity [Fe/H]−0.07±0.14 dex
Rotational velocity (v sin i)3.14 km/s
Other designations
λ2 Tuc, CD–70°40, FK5 34, HD 5457, HIP 4293, HR 270, SAO 248281[6]
Database references
SIMBADdata

Lambda2 Tucanae is a solitary[7] star in the southern constellation of Tucana. It is faintly visible to the naked eye with an apparent visual magnitude of +5.45.[2] Based upon an annual parallax shift of 14.6 mas as seen from Earth, it is located around 223 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.09 due to interstellar dust.[2]

This is an orange-hued K-type giant star on the red giant branch,[2] with a stellar classification of K2 III.[3] It has an estimated 1.75[2] times the mass of the Sun but after evolving away from the main sequence it has expanded to 9.8 times the Sun's radius. The star is radiating 39 times the solar luminosity from its photosphere at an effective temperature of 4,605 K.[1]

  1. ^ a b c d e f g h i Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f g Cite error: The named reference Jones2011 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 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. ^ Cite error: The named reference Anderson2012 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. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).