Iota Serpentis

Iota Serpentis
Location of ι Serpentis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension 15h 41m 33.05469s[1]
Declination 19° 40′ 13.4380″[1]
Apparent magnitude (V) 4.51[2]
Characteristics
Evolutionary stage main sequence
Spectral type B9V + A1V[3]
B−V color index +0.062±0.003[2]
Astrometry
Radial velocity (Rv)−17.20[4] km/s
Proper motion (μ) RA: -60.86[1] mas/yr
Dec.: -43.69[1] mas/yr
Parallax (π)17.16 ± 0.67 mas[1]
Distance190 ± 7 ly
(58 ± 2 pc)
Absolute magnitude (MV)+0.69[2]
Orbit[5]
Period (P)8015.0±6.3 d
Semi-major axis (a)0.21033±0.00047″
Eccentricity (e)0.0941±0.0028
Inclination (i)83.608±0.043°
Longitude of the node (Ω)69.684±0.033°
Periastron epoch (T)54,180±33 HMJD
Argument of periastron (ω)
(secondary)		80.5±1.8°
Details
A
Mass1.999[3] M☉
B
Mass1.984[3] M☉
Other designations
ι Ser, 21 Serpentis, BD+20° 3138, GC 21102, HD 140159, HIP 76852, HR 5842, SAO 101682, ADS 9744, CCDM J15416+1940[6]
Database references
SIMBADdata

ι Serpentis, Latinized as Iota Serpentis and abbreviated Iot Ser, is a triple star[7] system in the constellation Serpens, in its head (Serpens Caput). It is approximately 190 light years from Earth.[1]

At the centre of the system is a spectroscopic binary, Iota Serpentis A and B. These are both white main sequence dwarfs and both have apparent magnitudes of +5.3. This binary has an orbital period variously reported as 11[8] or 22[5] years. First discovered as an astrometric binary, the pair have now been resolved and visual orbits have been derived.[5]

There are two visual companions, Iota Serpentis C, a 13th magnitude star 143 arcseconds away and Iota Serpentis D, a 12th magnitude star 151 arcseconds distant.

  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 Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference martin was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Evans1967 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Muterspaugh2010 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference vanDenBos1965 was invoked but never defined (see the help page).