Rho Serpentis

Rho Serpentis, Latinized from ρ Serpentis, is a single^[11] star in the Caput section of the equatorial Serpens constellation. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude of +4.78.^[4] The distance to this star is approximately 375 light years based on parallax,^[3] but it is drifting closer to the Sun with a radial velocity of −62 km/s.^[6]

Rho Serpentis

A light curve for Rho Serpentis, plotted from Hipparcos data[1][2]
Observation data Epoch J2000      Equinox J2000
Constellation	Serpens
Right ascension	15h 51m 15.90985s[3]
Declination	+20° 58′ 40.5166″[3]
Apparent magnitude (V)	4.78[4]
Characteristics
Spectral type	K4.5III[5]
U−B color index	+1.88[4]
B−V color index	+1.54[4]
Astrometry
Radial velocity (Rv)	−61.96[6] km/s
Proper motion (μ)	RA: −53.32[3] mas/yr Dec.: +18.87[3] mas/yr
Parallax (π)	8.70 ± 0.30 mas[3]
Distance	370 ± 10 ly (115 ± 4 pc)
Absolute magnitude (MV)	−0.56[7]
Details
Radius	47.84+0.49 −1.19[8] R☉
Luminosity	491.9±22.3[8] L☉
Surface gravity (log g)	1.68[9] cgs
Temperature	3,930+50 −20[8] K
Metallicity [Fe/H]	−0.08[7] dex
Other designations
ρ Ser, 38 Serpentis, NSV 7300, BD+21°2829, GC 21311, HD 141992, HIP 77661, HR 5899, SAO 84037[10]
Database references
SIMBAD	data

This is an aging giant star with a stellar classification of K4.5III.^[5] It is a suspected variable star of unknown type, with an I-band brightness ranging from 3.29 down to 3.44 magnitude.^[12] Hipparcos photometry revealed a microvariability with a frequency of 0.17017 cycles per day and an amplitude of 0.0080.^[2] With the supply of hydrogen exhausted at its core, it has expanded and now has 48^[8] times the Sun's girth. The star is radiating 492^[8] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,930 K.^[8]

References

1. "/ftp/cats/more/HIP/cdroms/cats", Centre de Données astronomiques de Strasbourg, Strasbourg astronomical Data Center, retrieved 15 October 2022.
2. Koen, Chris; Eyer, Laurent (2002). "New periodic variables from the Hipparcos epoch photometry". Monthly Notices of the Royal Astronomical Society. 331 (1): 45–59. arXiv:astro-ph/0112194. Bibcode:2002MNRAS.331...45K. doi:10.1046/j.1365-8711.2002.05150.x. S2CID 10505995.
3. 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. S2CID 18759600. Vizier catalog entry
4. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
5. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
6. Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304
7. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
8. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
9. McWilliam, Andrew (December 1990). "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances". Astrophysical Journal Supplement Series. 74: 1075–1128. Bibcode:1990ApJS...74.1075M. doi:10.1086/191527.
10. "rho Ser". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-17.
11. Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
12. Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.