Kappa1 Apodis

Kappa1 Apodis
Location of Kappa1 Apodis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension 15h 31m 30.82213s[1]
Declination −73° 23′ 22.5295″[1]
Apparent magnitude (V) 5.52[2]
Characteristics
Spectral type B1npe[3]
U−B color index −0.791[2]
B−V color index −0.128[2]
Variable type γ Cas[4]
Astrometry
Radial velocity (Rv)+62[5] km/s
Proper motion (μ) RA: +0.996[1] mas/yr
Dec.: −18.345[1] mas/yr
Parallax (π)3.0798 ± 0.0717 mas[1]
Distance1,060 ± 20 ly
(325 ± 8 pc)
Absolute magnitude (MV)−2.47[6]
Details
A
Mass11.8±1.0[7] M☉
Luminosity2,120[6] L☉
Surface gravity (log g)3.90[8] cgs
Temperature21,500[8] K
Age5.6±1.0[9] Myr
B
Mass1.60±0.14[7] M☉
Other designations
κ1 Aps, CD−72°1139, CPD−72°1802, FK5 567, HD 137387, HIP 76013, HR 5730, SAO 257289[10]
Database references
SIMBADdata

Kappa1 Apodis, Latinized from κ1 Apodis, is a binary star[3] system in the southern circumpolar constellation of Apus. Based upon parallax measurements, it is located roughly 1,060 light-years (325 parsecs) from Earth. The combined apparent visual magnitude of the system is 5.52,[2] indicating that this is a faint, naked eye star that can be viewed in dark suburban skies. It is moving away from the Sun with a radial velocity of +62 km/s.[5]

A light curve for Kappa1 Apodis, plotted from TESS data[11]

This is a spectroscopic binary system, made up of a Be star and a Subdwarf O star, which complete an orbit around each other every 192 days.[7] The combined spectrum matches a stellar classification of B1npe.[3] The 'e' suffix indicates that this is a Be star with emission lines in the spectrum. An 'n' means that the absorption lines in the spectrum are broadened from the Doppler effect as a result of rapid rotation. Finally, the 'p' shows some peculiarity in the spectrum. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +5.43 to +5.61.

This is a runaway star with a peculiar velocity of 69.8±4.7 km/s.[9] Because it is a binary star system, it was most likely not turned into a runaway system as the result of a supernova explosion.[3] A companion star is a 12th magnitude orange K-type subgiant located at an angular separation of 27 arcseconds.

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  2. ^ a b c d Cite error: The named reference apjs15_459 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference apj721_1_469 was invoked but never defined (see the help page).
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  5. ^ a b Cite error: The named reference rgcrv was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference wang was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference aaa515_A11 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference mnras410_1_190 was invoked but never defined (see the help page).
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  11. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).