Iota Serpentis

Iota Serpentis

Observation data Epoch J2000      Equinox J2000
Constellation	Serpens
Right ascension	15^h 41^m 33.05469^s [1]
Declination	19° 40′ 13.4380″ [1]
Apparent magnitude (V)	4.51 [2]
Characteristics
Spectral type	A1V + A1V [2]
B−V color index	+0.06 [2]
Astrometry
Radial velocity (Rv)	-17.20[3] km/s
Proper motion (μ)	RA: -60.86[1] mas/yr Dec.: -43.69[1] mas/yr
Parallax (π)	17.16 ± 0.67[1] mas
Distance	190 ± 7 ly (58 ± 2 pc)
Absolute magnitude (MV)	0.68 [4]
Other designations
21 Serpentis, GC 21102, HIP 76852, HR 5842, HD 140159, SAO 101682, ADS 9744, CCDM J15416+1940 [2]
Database references
SIMBAD	data

Iota Serpentis (ι Ser, ι Serpentis) is a star 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 A-type main sequence dwarfs and both have apparent magnitudes of +5.3. This binary has an orbital period variously reported as 11^[5] or 22^[6] years; spectroscopic evidence indicates a third companion of A and B. A and B also have two distant companions, Iota Serpentis C, a 13th magnitude star 143 arcseconds away and Iota Serpentis D, a 12th magnitude star 151 arcseconds distant.

References

1. van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
2. "Iota Serpentis". SIMBAD Astronomical Database. Retrieved 2015-10-17.
3. Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E
4. Absolute magnitude calculated as $M = m + 5 (1 + \log_{10}{p})\!\,$, where $M$ is the star's absolute magnitude, $m$ is the star's apparent magnitude, and $p$ is the star's measured parallax in arcseconds.
5. van den Bos, W. H. (1965). "Note on the Double Star Iota Serpentis". Monthly Notes of the Astronomical Society of Southern Africa 24: 123. Bibcode:1965MNSSA..24..123V.
6. Muterspaugh, Matthew W.; et al. (2010). "The Phases Differential Astrometry Data Archive. II. Updated Binary Star Orbits and a Long Period Eclipsing Binary". The Astronomical Journal 140 (6): 1623–1630. arXiv:1010.4043. Bibcode:2010AJ....140.1623M. doi:10.1088/0004-6256/140/6/1623.