Delta Crateris

Delta Crateris (δ Crt, δ Crateris; traditional name: Labrum) is a solitary[9] star in the southern constellation of Crater. With an apparent visual magnitude of 3.56,[2] it is the brightest star[10] in this rather dim constellation. It has an annual parallax shift of 17.56[1] mas as measured from Earth, indicating Delta Crateris lies at a distance of 163 ± 4 light years from the Sun.

δ Crateris
Location of δ Crateris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Crater
Right ascension 11h 19m 20.44756s[1]
Declination −14° 46′ 42.7413″[1]
Apparent magnitude (V) 3.56[2]
Characteristics
Spectral type K0 III[2]
B−V color index 1.12[2]
Astrometry
Radial velocity (Rv)−4.94±0.21[3] km/s
Proper motion (μ) RA: −124.67[1] mas/yr
Dec.: +207.59[1] mas/yr
Parallax (π)20.0507 ± 0.5308[4] mas
Distance163 ± 4 ly
(50 ± 1 pc)
Absolute magnitude (MV)−0.321[5]
Details
Mass1.56[6] M☉
Radius22.44±0.28[7] R☉
Luminosity171.4±9.0[7] L☉
Surface gravity (log g)2.59[2] cgs
Temperature4,510±15[6] K
Metallicity [Fe/H]−0.48[2] dex
Rotational velocity (v sin i)0.0[3] km/s
Age2.89[6] Gyr
Other designations
δ Crt, 12 Crateris, BD−13° 3345, FK5 426, HD 98430, HIP 55282, HR 4382, SAO 156605.[8]
Database references
SIMBADdata

This is an evolved orange-hued giant star belonging to the spectral class K0 III. Delta Crateris is a member of the so-called red clump, indicating that it is generating energy through the thermonuclear fusion of helium at its core.[5] The star has an estimated 1.56[6] times the mass of the Sun but has expanded to 22.44±0.28[7] times the Sun's radius.

The metallicity of the star – what astronomers term the abundance of elements other than hydrogen and helium – is only 33% that of the Sun.[2] It is around 2.89[6] billion years old with a rotation rate that is too small to measure; the projected rotational velocity is 0.0 km/s.[3] Delta Crateris is radiating 171.4±9.0 as much luminosity as the Sun from its outer envelope at an effective temperature of 4,510±15 K.[6]

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, S2CID 18759600.
  2. Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M.
  3. Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  4. 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.
  5. Soubiran, C.; et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics, 480 (1): 91–101, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788, S2CID 16602121.
  6. Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  7. Berio, P.; et al. (November 2011), "Chromosphere of K giant stars. Geometrical extent and spatial structure detection", Astronomy & Astrophysics, 535: A59, arXiv:1109.5476, Bibcode:2011A&A...535A..59B, doi:10.1051/0004-6361/201117479, S2CID 17171848.
  8. "del Crt". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-02.
  9. 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.
  10. Ridpath, Ian (2012), A Dictionary of Astronomy, OUP Oxford, p. 108, ISBN 978-0199609055.
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