Astronomy:Gliese 42

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Short description: Star in the constellation of Sculptor
Gliese 42
Observation data
Equinox J2000.0]] (ICRS)
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[4] mas
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.

Debris disk

An infrared excess has been detected around this star,[11] most likely indicating the presence of a circumstellar disk at a radius of 45.7 Astronomy:astronomical unit|astronomical units (6.84×109 km; 4.25×109 mi). The temperature of this dust was initially estimated as 30 K (−243.2 °C; −405.7 °F)[6] according to measurement by Herschel Space Observatory. Later that measurement was deemed questionable,[12] and fixed temperature of 62 K (−211.2 °C; −348.1 °F) was obtained in 2020.[13]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode: 2006AJ....132..161G. 
  3. ↑ 3.0 3.1 Soubiran, C. et al. (April 2013). "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release". Astronomy & Astrophysics 552: 11. doi:10.1051/0004-6361/201220927. A64. Bibcode: 2013A&A...552A..64S. 
  4. ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  5. ↑ 5.0 5.1 5.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  6. ↑ 6.0 6.1 6.2 Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series 225 (1): 24, doi:10.3847/0067-0049/225/1/15, 15, Bibcode: 2016ApJS..225...15C. 
  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, doi:10.3847/1538-4357/aa6a14, Bibcode: 2017ApJ...839...97A 
  8. ↑ Pace, G. (March 2013), "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram", Astronomy & Astrophysics 551: 4, doi:10.1051/0004-6361/201220364, L8, Bibcode: 2013A&A...551L...8P. 
  9. ↑ "HD 5133". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+5133. 
  10. ↑ Bakos, Gáspár Á. et al. (July 2002), "Revised Coordinates and Proper Motions of the Stars in the Luyten Half-Second Catalog", The Astrophysical Journal Supplement Series 141 (1): 187–193, doi:10.1086/340115, Bibcode: 2002ApJS..141..187B. 
  11. ↑ Eiroa, C. et al. (July 2013). "DUst around NEarby Stars. The survey observational results". Astronomy & Astrophysics 555: A11. doi:10.1051/0004-6361/201321050. Bibcode: 2013A&A...555A..11E. 
  12. ↑ THE HERSCHEL COLD DEBRIS DISKS: CONFUSION WITH THE EXTRAGALACTIC BACKGROUND AT 160 μm
  13. ↑ Su, Kate Y L.; Kennedy, Grant M.; Yelverton, Ben (2020), "No significant correlation between radial velocity planet presence and debris disc properties", Monthly Notices of the Royal Astronomical Society 495 (2): 1943–1957, doi:10.1093/mnras/staa1316 

External links



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