Gamma Crateris

Gamma Crateris
Location of γ Crateris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Crater[1]
Right ascension 11h 24m 52.924s[2]
Declination −17° 41′ 02.443″[2]
Apparent magnitude (V) 4.06[1]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A9 V[4]
U−B color index +0.09[5]
B−V color index +0.216±0.006[1]
Astrometry
Radial velocity (Rv)+0.58±0.20[2] km/s
Proper motion (μ) RA: −96.811 mas/yr[2]
Dec.: +3.650 mas/yr[2]
Parallax (π)37.7065±0.1972 mas[2]
Distance86.5 ± 0.5 ly
(26.5 ± 0.1 pc)
Absolute magnitude (MV)+2.05[1]
Details
γ Crt A
Mass1.83[6] M☉
Radius1.96[6] R☉
Luminosity18.8[7] L☉
Surface gravity (log g)4.21±0.14[8] cgs
Temperature8,020±273[8] K
Metallicity [Fe/H]−0.01[9] dex
Rotational velocity (v sin i)144[10] km/s
Age757[8] Myr
γ Crt B
Mass0.76[6] M☉
Radius0.72[6] R☉
Luminosity0.24[6] L☉
Surface gravity (log g)4.60[6] cgs
Temperature4,755[6] K
Other designations
γ Crt, 15 Crateris, BD−16°3244, FK5 431, GC 15669, HD 99211, HIP 55705, HR 4405, SAO 156661, WDS J11249-1741A[11]
Database references
SIMBADdata

Gamma Crateris is a binary star[12] system that is divisible with a small amateur telescope,[13] and is located at the center of the southern constellation of Crater. Its name is a Bayer designation that is Latinized from γ Crateris and abbreviated Gamma Crt or γ Crt. This system is visible to the naked eye as a point of light with an apparent visual magnitude of 4.06.[1] With an annual parallax shift of 37.71 mas as seen from Earth, this star is located at a distance of 86.5 light-years (26.5 pc) from the Sun. Based upon the motion of this system through space, it is a potential member of the Castor Moving Group.[14]

Properties

The primary, component A, is a white-hued A-type main sequence star with a stellar classification of A9 V.[4] The star has an estimated 1.8 times the mass of the Sun and around twice the Sun's radius.[6] It is about 757 million years old[8] and is spinning rapidly with a projected rotational velocity of 144 km/s.[10] The primary is radiating 18.8 times the solar luminosity[7] from its photosphere at an effective temperature of 8,020 K.[8] Based upon the detection of an infrared excess, the star may host an orbiting debris disk.[7] However, this finding remains in doubt.[15]

The star was confirmed by Gabriel Cristian Neagu and Jan Ovidiu Tercu as a variable of Delta Scuti type. The variability has an amplitude of 0.001 magnitudes and a main period of 0.03647 d  (52.52 min). The variability was discovered during the datamining activity with the goal of increasing the student's investigative competences.[16]

The companion, component B, is a magnitude 9.6 star with an estimated mass 75% that of the Sun. As of 2010, the companion was located at an angular separation of 4.98 arc seconds along a position angle of 93.1° relative to the primary. This is equivalent to a projected separation of 125.6 AU.[12] This star may be the source of the X-ray emission detected coming from this system.[17]

References

  1. 1 2 3 4 5 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015 XHIP record for this object at VizieR.
  2. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ↑ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  4. 1 2 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  5. ↑ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  6. 1 2 3 4 5 6 7 8 Stassun, Keivan G.; et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467.
  7. 1 2 3 Hales, Antonio S.; et al. (April 2017), "Atomic gas in debris discs", Monthly Notices of the Royal Astronomical Society, 466 (3): 3582–3593, arXiv:1612.05465, Bibcode:2017MNRAS.466.3582H, doi:10.1093/mnras/stw3274, S2CID 119223132.
  8. 1 2 3 4 5 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  9. ↑ Saffe, C.; et al. (October 2008), "Spectroscopic metallicities of Vega-like stars", Astronomy and Astrophysics, 490 (1): 297–305, arXiv:0805.3936, Bibcode:2008A&A...490..297S, doi:10.1051/0004-6361:200810260, S2CID 15059920.
  10. 1 2 Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
  11. ↑ "gam Crt", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-03-02.
  12. 1 2 De Rosa, R. J.; et al. (2013), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216, arXiv:1311.7141, Bibcode:2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932, S2CID 88503488.
  13. ↑ Monks, Neale (2010), Go-To Telescopes Under Suburban Skies, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 113, ISBN 978-1441968517.
  14. ↑ Nakajima, Tadashi; et al. (September 2010), "Potential Members of Stellar Kinematical Groups within 20 pc of the Sun", The Astronomical Journal, 140 (3): 713–722, Bibcode:2010AJ....140..713N, doi:10.1088/0004-6256/140/3/713.
  15. ↑ Ertel, S.; et al. (October 2014), "A near-infrared interferometric survey of debris-disk stars. IV. An unbiased sample of 92 southern stars observed in H band with VLTI/PIONIER", Astronomy & Astrophysics, 570: 20, arXiv:1409.6143, Bibcode:2014A&A...570A.128E, doi:10.1051/0004-6361/201424438, S2CID 9594917, A128.
  16. ↑ "VSX : Detail for gam Crt". www.aavso.org. Retrieved 2021-03-31.
  17. ↑ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677–684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.