47 Capricorni

This article is about c2 Capricorni. For other stars with this Bayer designation, see c Capricorni.
47 Capricorni

A light curve for AG Capricorni, plotted from Hipparcos data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Capricornus
Right ascension 21h 46m 16.26887s[2]
Declination −09° 16′ 33.3799″[2]
Apparent magnitude (V) 6.00[3] (5.90 - 6.14)[4]
Characteristics
Evolutionary stage giant
Spectral type M2III[5]
B−V color index 1.629±0.010[3]
Variable type SRb[4]
Astrometry
Radial velocity (Rv)+19.80±0.89[6] km/s
Proper motion (μ) RA: +18.731[2] mas/yr
Dec.: +8.387[2] mas/yr
Parallax (π)2.7933 ± 0.2052 mas[2]
Distance1,170 ± 90 ly
(360 ± 30 pc)
Absolute magnitude (MV)−1.76[3]
Details
Radius102+11
−10[2] R☉
Luminosity1,940±162[2] L☉
Temperature3,784+188
−186[2] K
Other designations
c2 Cap, 47 Cap, AG Cap, BD−09°5833, HD 207005, HIP 107487, HR 8318, SAO 145648[7]
Database references
SIMBADdata

47 Capricorni is a variable star located around 1,170[2] light years from the Sun in the southern constellation Capricornus,[7] near the northern border with Aquarius. It has the variable star designation of AG Capricorni and a Bayer designation of c2 Capricorni;[8] 47 Capricorni is the Flamsteed designation. This object is visible to the naked eye as a dim, red-hued point of light with an apparent visual magnitude that varies between 5.90 and 6.14. The star is receding from the Earth with a heliocentric radial velocity of +20 km/s.[6]

In 1963, Alan William James Cousins announced that 47 Capricorni is a variable star.[9] It was given its variable star designation in 1973.[10]

This is an aging red giant star with a stellar classification of M2III.[5] It is a semiregular variable star of subtype SRb with a period of 30.592 days and a maximum brightness of 5.9 magnitude.[4] With the supply of hydrogen at its core exhausted, the star has expanded to around 102[2] times the Sun's radius. It is radiating 1,940[2] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,784 K.[2]

References

  1. ^ "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
  2. ^ a b c d e f g h i j k l 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.
  3. ^ a b c 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, S2CID 119257644.
  4. ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. 1. Bibcode:2009yCat....102025S.
  5. ^ a b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  6. ^ a b Famaey, B.; et al. (2009). "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations". Astronomy and Astrophysics. 498 (2): 627. arXiv:0901.0934. Bibcode:2009A&A...498..627F. doi:10.1051/0004-6361/200810698. S2CID 18739721.
  7. ^ a b "47 Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-05-12.
  8. ^ Kostjuk, N. D. (2002). "HD 207005". HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index. Institute of Astronomy of Russian Academy of Sciences; CDS. IV/27A
  9. ^ Cousins, A. W. J. (1963). "Photometric Data for Stars in the Equatorial Zone (Third List)". Monthly Notes of the Astron. Soc. Southern Africa. 22: 12. Bibcode:1963MNSSA..22...12C. Retrieved 8 December 2024.
  10. ^ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (October 1973). "59th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 834. Bibcode:1973IBVS..834....1K. Retrieved 8 December 2024.