Astronomy:47 Capricorni

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Short description: Star in the constellation Capricornus
47 Capricorni
AGCapLightCurve.png
A light curve for AG Capricorni, plotted from Hipparcos data[1]
Observation data
Equinox J2000.0]] (ICRS)
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[2] mas
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]

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". ESA. https://www.cosmos.esa.int/web/hipparcos/interactive-data-access. 
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 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. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. 3.0 3.1 3.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  4. 4.0 4.1 4.2 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs 1. Bibcode2009yCat....102025S. 
  5. 5.0 5.1 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey 5. Bibcode1999MSS...C05....0H. 
  6. 6.0 6.1 Famaey, B. et al. (2009). "Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations". Astronomy and Astrophysics 498 (2): 627. doi:10.1051/0004-6361/200810698. Bibcode2009A&A...498..627F. 
  7. 7.0 7.1 "47 Cap". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=47+Cap. 
  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. http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=IV/27A/catalog&recno=3684.  IV/27A