Gliese 42

Gliese 42
Observation data
Epoch J2000      Equinox J2000
Constellation Sculptor
Right ascension 00h 53m 00.71555s[1]
Declination −30° 21′ 25.1677″[1]
Apparent magnitude (V) +7.3029[1]
Characteristics
Spectral type K2.5 V (k)[2]
B−V color index 0.936[1]
Astrometry
Radial velocity (Rv)−13.021±0.0064[3] km/s
Proper motion (μ) RA: +620.35[1] mas/yr
Dec.: +30.26[1] mas/yr
Parallax (π)71.5472 ± 0.0573 mas[4]
Distance45.59 ± 0.04 ly
(13.98 ± 0.01 pc)
Absolute magnitude (MV)+6.39[5]
Details
Radius0.660[6] R☉
Luminosity0.29[5] L☉
Surface gravity (log g)4.55[2] cgs
Temperature4,822[2] K
Metallicity [Fe/H]−0.21[2] dex
Rotational velocity (v sin i)1.8[7] km/s
Age6.67±4.74[8] Gyr
Other designations
BD−31° 325, Gaia DR2 5031808453624044800, GJ 42, HD 5133, HIP 4148, SAO 192793, LTT 498, 2MASS J00530108-3021249[9]
Database references
SIMBADdata

Gliese 42 is a star in the southern constellation of Sculptor. It is too faint to be seen with the naked eye, having an apparent visual magnitude of +7.3.[1] The annual parallax shift of 70.56 mas provides a distance estimate of 46 light years. It has a relatively high proper motion, advancing 0.62[10] arcseconds across the sky per annum, and is moving closer to the Sun with a radial velocity of −13 km/s.[3]

The spectrum of the star matches a stellar classification of K2.5 V (k),[2] indicating it is an ordinary K-type main-sequence star that is generating energy through hydrogen fusion at its core. It is radiating 29%[5] of the Sun's luminosity from its photosphere at an effective temperature of 4,822 K.[2] The star has 66%[6] of the Sun's radius.

  1. ^ a b c d e f g Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Gray2006 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Soubiran2013 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Cotten2016 was invoked but never defined (see the help page).
  7. ^ Andretta, Vincenzo; Giampapa, Mark S.; Covino, Elvira; Reiners, Ansgar; Beeck, Benjamin (2017), "ESTIMATES OF ACTIVE REGION AREA COVERAGE THROUGH SIMULTANEOUS MEASUREMENTS OF HE I λλ 5876 AND 10830 LINES", The Astrophysical Journal, 839 (2): 97, arXiv:1703.10060, Bibcode:2017ApJ...839...97A, doi:10.3847/1538-4357/aa6a14, S2CID 119201107
  8. ^ Cite error: The named reference Pace2013 was invoked but never defined (see the help page).
  9. ^ "HD 5133". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-01-01.
  10. ^ Cite error: The named reference apjss141_1_187 was invoked but never defined (see the help page).