Lambda Octantis
Star in the constellation Octans / From Wikipedia, the free encyclopedia
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]
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] |
Distance | 398 ± 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] |
Distance | 409 ± 3 ly (125.5 ± 0.9 pc) |
Absolute magnitude (MV) | +2.20[5] |
Details | |
A | |
Radius | 13.23+0.41 −0.50[7] R☉ |
Luminosity | 102.4±1.3[7] L☉ |
Temperature | 5,048+98 −76[7] K |
Rotational velocity (v sin i) | 1.8[9] km/s |
Age | 200[5] Myr |
Other designations | |
Database references | |
SIMBAD | data |
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]