Lambda Serpentis

Lambda Serpentis
Location of λ Serpentis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Serpens
Right ascension 15h 46m 26.61423s[1]
Declination +07° 21′ 11.0475″[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: −224.0±0.2 mas/yr[1]
Dec.: −69.8±0.3 mas/yr[1]
Parallax (π)83.92 ± 0.15 mas[1]
Distance38.87 ± 0.07 ly
(11.92 ± 0.02 pc)
Absolute magnitude (MV)4.01[5]
Details[6]
Mass1.09±0.04 M☉
Radius1.363±0.031 R☉
Luminosity1.98±0.023 L☉
Surface gravity (log g)4.09[7] cgs
Temperature5,901±78 K
Metallicity [Fe/H]−0.03[7] dex
Rotation24.3+3.7
−4.9 d
Rotational velocity (v sin i)3[8] km/s
Age5.4±0.7 Gyr
Other designations
λ Ser, 27 Serpentis, NSV 7246, BD+7°3023, HD 141004, HIP 77257, HR 5868, SAO 121186, 2MASS J15462661+0721109[3]
Database references
SIMBADdata

Lambda Serpentis, Latinized from 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, this star lies at a distance of about 38.9 light-years (11.9 parsecs) from Earth.[1] 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.[9]

This star is 36% larger and 9% more massive than the Sun, although it has a similar stellar classification. 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 5,901 K.[6] A periodicity of 1837 days (5.03 years) was suspected by Morbey & Griffith (1987),[10] but it is probably bound to stellar activity. However, McDonald Observatory team has set limits to the presence of one or more exoplanets[10] around Lambda Serpentis with masses between 0.16 and 2 Jupiter masses and average separations spanning between 0.05 and 5.2 Astronomical Units.

  1. ^ a b c d e Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference yerkes53 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference gcsrv was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Holmberg2009 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference metcalfe was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference aaa338_161 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference csrv was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference aaa449_3_1233 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference apj317_1_343 was invoked but never defined (see the help page).