Lambda Serpentis

Lambda Serpentis (λ Ser, λ Serpentis) is a star in the constellation Serpens, in its head (Serpens Caput). It has an apparent visual magnitude of 4.43,[2] making it visible to the naked eye. Based upon parallax measurements from the Hipparcos satellite, this star lies at a distance of about 39.5 light-years (12.1 parsecs) from Earth.[1] This star is larger and more massive than the Sun, although it has a similar stellar classification.[3] It is shining with nearly double the Sun's luminosity and this energy is being radiated from the star's outer atmosphere at an effective temperature of 5,884 K.[9]

Lambda Serpentis
Location of λ Serpentis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension  15h 46m 26.614s[1]
Declination +07° 21′ 11.04″[1]
Apparent magnitude (V) 4.43[2]
Characteristics
Spectral type G0 V[3]
U−B color index +0.11[2]
B−V color index +0.60[2]
Variable type Suspected
Astrometry
Radial velocity (Rv)−66.4[4] km/s
Proper motion (μ) RA: -224.00 ± 0.29[1] mas/yr
Dec.: -70.64 ± 0.27[1] mas/yr
Parallax (π)82.48 ± 0.32[1] mas
Distance39.5 ± 0.2 ly
(12.12 ± 0.05 pc)
Absolute magnitude (MV)4.01[5]
Details
Mass1.14[6] M☉
Radius1.060 ± 0.152[7] R☉
Luminosity1.94[6] L☉
Surface gravity (log g)4.09[8] cgs
Temperature5,884 ± 4.4[9] K
Metallicity [Fe/H]−0.03[8] dex
Rotational velocity (v sin i)3[10] km/s
Age3.8–6.7[11] Gyr
Other designations
27 Serpentis, BD +7°3023, HD 141004, HIP 77257, HR 5868, SAO 121186.[3]
Database references
SIMBADdata

Lambda Serpentis is moving toward the Solar System with a radial velocity of 66.4 km s−1.[4] In about 166,000 years, this system will make its closest approach of the Sun at a distance of 7.371 ± 0.258 light-years (2.260 ± 0.079 parsecs), before moving away thereafter.[12]

A periodicity of 1837 days (5.03 years) was suspected by Morbey & Griffith (1987),[13] but it is probably bound to stellar activity. However, McDonald Observatory team has set limits to the presence of one or more planets[13] around Lambda Serpentis with masses between 0.16 and 2 Jupiter masses and average separations spanning between 0.05 and 5.2 Astronomical Units.

See also

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. Johnson, H. L.; Morgan, W. W. (1953). "Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas". Astrophysical Journal. 117: 313–352. Bibcode:1953ApJ...117..313J. doi:10.1086/145697.
  3. "lam Ser -- Spectroscopic binary". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-12-15.
  4. Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  5. Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191.
  6. Valenti, J. A.; Fishcer, D. A. (2005). "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs". Astrophysical Journal Supplement Series. 159 (1): 141–166. Bibcode:2005ApJS..159..141V. doi:10.1086/430500.
  7. van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085.
  8. Fuhrmann, Klaus (October 1998). "Nearby stars of the Galactic disk and halo". Astronomy and Astrophysics. 338: 161–183. Bibcode:1998A&A...338..161F.
  9. Kovtyukh; Soubiran, C.; Belik, S. I.; Gorlova, N. I. (2003). "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios". Astronomy and Astrophysics. 411 (3): 559–564. arXiv:astro-ph/0308429. Bibcode:2003A&A...411..559K. doi:10.1051/0004-6361:20031378.
  10. Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1): 1. Bibcode:1970CoAsi.239....1B.
  11. Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
  12. Dybczyński, P. A. (April 2006), "Simulating observable comets. III. Real stellar perturbers of the Oort cloud and their output", Astronomy and Astrophysics, 449 (3): 1233–1242, Bibcode:2006A&A...449.1233D, doi:10.1051/0004-6361:20054284
  13. Morbey, C. L.; Griffith, R. F. (1987). "On the reality of certain spectroscopic orbits". Astrophysical Journal. 317 (1): 343–352. Bibcode:1987ApJ...317..343M. doi:10.1086/165281.

Further reading
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.