HD 154556

HD 154556
location of HD 154556 in red
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Apus
Right ascension 17h 12m 19.93421s[1]
Declination −70° 43′ 15.8963″[1]
Apparent magnitude (V) 6.21±0.01[2]
Characteristics
Evolutionary stage subgiant
Spectral type K1 IV CN3[3]
U−B color index +1.04[4]
B−V color index +1.06[4]
Astrometry
Radial velocity (Rv)−24±0.4[5] km/s
Proper motion (μ) RA: +49.060 mas/yr[1]
Dec.: −78.104 mas/yr[1]
Parallax (π)14.3386 ± 0.0224 mas[1]
Distance227.5 ± 0.4 ly
(69.7 ± 0.1 pc)
Absolute magnitude (MV)+2.10[6]
Details
Mass1.25[7] M☉
Radius6.35±0.32[8] R☉
Luminosity19.7±0.1[1] L☉
Surface gravity (log g)2.90±0.25[9] cgs
Temperature4,677[10] K
Metallicity [Fe/H]+0.04±0.09[9] dex
Rotational velocity (v sin i)<1[11] km/s
Age3.52+0.36
−0.37[1] Gyr
Other designations
55 G. Apodis[12], CD−70°1498, CPD−70°2361, GC 23140, HD 154556, HIP 84158, HR 6357, SAO 257472[13]
Database references
SIMBADdata

HD 154556, also known as HR 6357, is a solitary orange-hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.21,[2] placing it near the limit for naked eye visibility. The star is located relatively close at a distance of 228 light years based on Gaia DR3 parallax measurements,[1] but it is drifter closer with a heliocentric radial velocity of −24 km/s.[5] At its current distance, HD 154556's brightness is diminished by 0.26 magnitudes due to interstellar dust.[14] It has an absolute magnitude of +2.10.[6]

HD 154556 has a stellar classification of K1 IV CN3,[3] indicating that it is an evolved K-type subgiant with a moderate abundance of cyano radicals in its spectrum, making it a CN star. It has 1.25 times the mass of the Sun[7] and is calculated to be 3.52 billion years old,[1] having expanded to 6.35 times the radius of the Sun.[8] It now radiates 19.7 times the luminosity of the Sun[1] from its enlarged photosphere at an effective temperature of 4,677 K.[10] It has a near solar metallicity[9] and spins slowly with a projected rotational velocity lower than 1 km/s.[11]

  1. ^ a b c d e f g h i Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Tycho2000 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Johnson1966 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 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 Cite error: The named reference Anders2019 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Kervella2004 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Randich1999 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference AP1999 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference De Medeiros2014 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Gontcharov2017 was invoked but never defined (see the help page).