HD 165259

HD 165259
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Apus
A
Right ascension 18h 12m 34.08358s[1]
Declination −73° 40′ 20.7691″[1]
Apparent magnitude (V) 5.91[2]
B
Right ascension 18h 12m 33.47381s[3]
Declination −73° 40′ 20.9419″[3]
Apparent magnitude (V) 9.03[2]
Characteristics
A
Spectral type F5V[4]
U−B color index +0.05[5]
B−V color index +0.46[5]
B
Spectral type G1 V[6]
U−B color index +0.74[6]
B−V color index +1.06[6]
Astrometry
Radial velocity (Rv)13.1±1[7] km/s
Absolute magnitude (MV)+2.74[8]
A
Proper motion (μ) RA: −91.400[1] mas/yr
Dec.: −254.341[1] mas/yr
Parallax (π)23.6778 ± 0.0399 mas[1]
Distance137.7 ± 0.2 ly
(42.23 ± 0.07 pc)
B
Proper motion (μ) RA: −62.130[3] mas/yr
Dec.: −241.999[3] mas/yr
Parallax (π)23.7101 ± 0.0338 mas[3]
Distance137.6 ± 0.2 ly
(42.18 ± 0.06 pc)
Orbit[9]
PrimaryA
CompanionB
Period (P)542 yr
Semi-major axis (a)98 AU
Orbit[9]
PrimaryAa
CompanionAb
Period (P)31.536 yr
Semi-major axis (a)13.3 AU
Details
Aa
Mass1.22[10] M☉
Radius2.04[1] R☉
Luminosity6.2[1] L☉
Surface gravity (log g)3.92[11] cgs
Temperature6,411±218[11] K
Metallicity [Fe/H]+0.26[12] dex
Rotational velocity (v sin i)<5[13] km/s
Age1.8+0.1
−0.2[13] Gyr
Ab
Mass0.76[9] M☉
B
Mass0.85[9] M☉
Surface gravity (log g)4.3[14] cgs
Temperature5,328[14] K
Metallicity [Fe/H]−0.22[14] dex
Other designations
67 G. Apodis[15], CD−73°1348, CPD−73°1888, GC 24731, HD 165259, HIP 89234, HR 6751, SAO 257571, WDS J18126-7340AB[16]
Database references
SIMBADdata

HD 165259, also known as HR 6751 is a triple star system located in the southern circumpolar constellation of Apus. It has an apparent magnitude of 5.86,[8] making it faintly visible to the naked eye Parallax measurements place the system at a distance of 138 light years,[1][3] and it is currently receding with a heliocentric radial velocity of 13.1 km/s.[7]

HD 165259 consists of two main sequence stars, with stellar classifications of F5 V[4] and G1 V,[6] separated by two arc-seconds as of 2020.[17] Speckle interferometry in 2008 revealed the primary to be a close binary itself, with the two components separated by 0.3″.[18] By 2020, the separation had decreased to 0.2″.[17] The outer pair take 542 years to complete a revolution while the inner pair complete their orbit within 32 years.[9]

At present the primary has 122% the mass of the Sun[10] and a slightly enlarged radius of 2.0 R☉ as it is nearing the end of its main sequence life.[1] It radiates at 6.2 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 6,411 K,[11] giving a yellow-white hue. HD 165259A has an iron abundance 82% above solar levels,[12] making it metal enriched. It is estimated to be nearly 2 billion years old and has a projected rotational velocity of less than 5 km/s.[13] HD 165259B has 85% the mass of the Sun[9] and an effective temperature of 5,328 K,[14] giving an orange glow. The faint star orbiting the primary has a mass 76% that of the Sun.[9]

  1. ^ a b c d e f g h i j Cite error: The named reference dr3a was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference tycho2 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference dr3b was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1975 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference aass34_1 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Corbally1984 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  9. ^ a b c d e f g Cite error: The named reference Tokovinin2014 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference starhorse was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference David2015 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Casagrande2011 was invoked but never defined (see the help page).
  13. ^ a b c Cite error: The named reference Nordstrom2004 was invoked but never defined (see the help page).
  14. ^ a b c d Cite error: The named reference Anders2022 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Gould1879 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  17. ^ a b Cite error: The named reference Mason2001 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference tokovinin2010 was invoked but never defined (see the help page).