Kappa2 Apodis

Kappa² Apodis is a double star in the southern circumpolar constellation of Apus. Its identifier is a Bayer designation that is Latinized from κ² Apodis, and abbreviated Kap² Aps or κ² Aps, respectively. This star is located at a distance of approximately 720 light-years (220 parsecs) from Earth, based upon parallax measurements with a 1.4% margin of error.^[2] They are approaching the Sun with a radial velocity of −19 km/s.^[5] The pair have a combined apparent visual magnitude of +5.65,^[3] which makes the system faintly visible to the naked eye.

For other stars with this name, see Kappa Apodis.

κ² Apodis

Location of κ2 Apodis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Apus[1]
Right ascension	15h 40m 21.355s[2]
Declination	−73° 26′ 48.00″[2]
Apparent magnitude (V)	5.65[3]
Characteristics
Spectral type	B7 III-IV + K0 V[4]
U−B color index	–0.38[3]
B−V color index	–0.04[3]
Astrometry
Radial velocity (Rv)	−19.0[5] km/s
Proper motion (μ)	RA: −15.517 mas/yr[2] Dec.: −26.408 mas/yr[2]
Parallax (π)	4.5583±0.0823 mas[2]
Distance	720 ± 10 ly (219 ± 4 pc)
Absolute magnitude (MV)	−1.24[1] + 6.50[6]
Details
κ2 Aps A
Mass	4.995±0.250[7] M☉
Radius	5.555±0.278[7] R☉
Luminosity	316[8] L☉
Surface gravity (log g)	3.86[8] cgs
Temperature	12,646[8] K
Age	130[8] Myr
κ2 Aps C[8]
Luminosity	0.25[6] L☉
Temperature	5,127[6] K
Other designations
κ2 Apodis, Kap2 Aps, κ2 Aps, CPD−73°1625, HD 138800, HIP 76750, HR 5782, SAO 257307[9]
Database references
SIMBAD	data

The brighter star, designated κ² Aps A, has a stellar classification of B7 III-IV, with the luminosity class of III-IV suggesting that it may lie in an intermediate stage between a subgiant and a giant star.^[10] Based on observations with TESS, it is a pulsating B star of the Maia type.^[11] This star is about 130^[8] million years old with an estimated 5 times the mass and 5.6 times the radius of the Sun.^[7] It is radiating 316^[8] times the luminosity of the Sun from its photosphere at an effective temperature of 12,646 K.^[8]

A faint companion, κ² Aps C,^[8] is a K-type main sequence star with a classification of K0 V. It has a visual magnitude of 12.5 and an angular separation of 15 arcseconds from the brighter member.^[4] The pair have a projected separation of around 2,520 au.^[6]