Lambda Octantis

Lambda Octantis
Location of λ Octantis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Octans
Right ascension 21h 50m 54.56355s[1]
Declination −82° 43′ 08.0450″[1]
Apparent magnitude (V) 5.27[2] (5.64 + 7.25)[3]
Characteristics
Spectral type G8-K0III[4] + kA3hA7VmA8[5]
U−B color index +0.47[6]/+2.20[5]
B−V color index +0.75[6]
Astrometry
A
Radial velocity (Rv)−10.18±0.13[7] km/s
Proper motion (μ) RA: +69.803[7] mas/yr
Dec.: −33.013[7] mas/yr
Parallax (π)8.1897 ± 0.0878 mas[7]
Distance398 ± 4 ly
(122 ± 1 pc)
Absolute magnitude (MV)+0.40[5]
B
Proper motion (μ) RA: +69.025[8] mas/yr
Dec.: −25.496[8] mas/yr
Parallax (π)7.9685 ± 0.0570 mas[8]
Distance409 ± 3 ly
(125.5 ± 0.9 pc)
Absolute magnitude (MV)+2.20[5]
Details
A
Radius13.23+0.41
−0.50[7] R☉
Luminosity102.4±1.3[7] L☉
Temperature5,048+98
−76[7] K
Rotational velocity (v sin i)1.8[9] km/s
Age200[5] Myr
Other designations
λ Oct, CPD−83°722, GC 30472, HD 206240, HIP 107843, HR 8280, SAO 258914, CCDM J21509-8243, WDS J21509-8243[10]
Database references
SIMBADdata

λ Octantis, Latinized as Lambda Octantis, is a binary star[3] system in the southern circumpolar constellation of Octans.[10] It is visible to the naked eye as a dim point of light with a combined apparent visual magnitude of 5.27.[2] The distance to this system is approximately 398–409 light years, based on parallax, but it is moving closer with a radial velocity of −10 km/s.[7]

The primary, designated component A, is an aging, yellow-hued star with a stellar classification of class G8-K0III[11] and a visual magnitude of 5.64.[3] Having exhausted the supply of hydrogen at its core, it has expanded and cooled off the main sequence, becoming a giant. At present it is about 200[5] million years old and has 13[7] times the girth of the Sun. This star is radiating 102[7] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 5,048 K.[7]

The magnitude 7.25[3] secondary companion, component B, is an Am star with a class of kA3hA7VmA8.[5] This notation indicates it has the calcium K line of an A3 class star, the hydrogen lines of a cooler A7 main sequence star, and the metal lines of an A8 star. As of 2008, it lies at an angular separation of 3.233″ from the primary.[3]

  1. ^ a b Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  5. ^ a b c d e f g Cite error: The named reference Corbally1984 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Mallama2014 was invoked but never defined (see the help page).
  7. ^ a b c d e f g h i j k Cite error: The named reference GaiaDR2a was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference GaiaDR2b was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference deMedeiros2014 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Hoffleit1991 was invoked but never defined (see the help page).