Xi Serpentis

Xi Serpentis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Serpens
Right ascension 17h 37m 35.19983s[1]
Declination −15° 23′ 54.7940″[1]
Apparent magnitude (V) 3.54[2]
Characteristics
Spectral type A9 IIIp Sr[3]
U−B color index +0.12[2]
B−V color index +0.27[2]
Astrometry
Radial velocity (Rv)−42.8±0.7[4] km/s
Proper motion (μ) RA: −42.10[1] mas/yr
Dec.: −59.94[1] mas/yr
Parallax (π)30.98 ± 0.19 mas[1]
Distance105.3 ± 0.6 ly
(32.3 ± 0.2 pc)
Absolute magnitude (MV)+1.00[5]
Orbit[6]
Period (P)2.2923 d
Eccentricity (e)0.00
Periastron epoch (T)2419210.191 JD
Semi-amplitude (K1)
(primary)		19.4 km/s
Details
ξ Ser Aa
Mass2.06[7] M☉
Luminosity30.6[8] L☉
Surface gravity (log g)3.55[3] cgs
Temperature7,217±41[7] K
Metallicity [Fe/H]+0.07[3] dex
Rotational velocity (v sin i)54[9] km/s
Age1.03[7] Gyr
ξ Ser Ab
Mass0.18[10] M☉
Other designations
ξ Ser, 55 Serpentis, BD−15° 4621, FK5 658, HD 159876, HIP 86263, HR 6561, SAO 160700[11]
Database references
SIMBADdata

Xi Serpentis, Latinized from ξ Serpentis, is a triple star[10] system in the Serpens Cauda (tail) section of the equatorial constellation Serpens. Based upon an annual parallax shift of 30.98 mas as seen from Earth,[1] it is located 105.3 light years from the Sun. The star system is visible to the naked eye with a base apparent visual magnitude of +3.54.[2] It is moving closer to the Sun and will make perihelion passage at a distance of 27 ly (8.2 pc) in around 690,000 years.[12]

The inner pair form a single-lined spectroscopic binary with an orbital period of 2.29 days following a circular orbit with an eccentricity of 0.00.[6] The primary, component Aa, has a visual magnitude of 3.54.[13] It is a white-hued G-type giant star with a stellar classification of A9 IIIp Sr.[3] This indicates it is a chemically peculiar Ap star with an abnormal abundance of strontium. The primary has around double[7] the mass of the Sun, while its close companion, component Ab,[13] has only 18%[10] of the Sun's mass.

The third member, component B, is a magnitude 13.0[13] common proper motion companion.[10] As of 2012, it was located at an angular separation of 24 arc seconds along a position angle of 78° from the inner pair.[13] It has about 27% of the Sun's mass and an estimated orbital period of 14,763 years.[10]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference luck2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Royer2002 was invoked but never defined (see the help page).
  10. ^ a b c d e Cite error: The named reference Tokovinin2006 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Bailer-Jones2015 was invoked but never defined (see the help page).
  13. ^ a b c d Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).