Astronomy:30 Aquarii

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Short description: Star in the constellation Aquarius
30 Aquarii
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Aquarius
Right ascension  22h 03m 16.45803s[1]
Declination −06° 31′ 20.6748″[1]
Apparent magnitude (V) 5.558[2]
Characteristics
Evolutionary stage giant
Spectral type K1 IV[3] or G8 III[4]
B−V color index 0.951[2]
Variable type Constant[5]
Astrometry
Radial velocity (Rv)39.74[2] km/s
Proper motion (μ) RA: +45.635[1] mas/yr
Dec.: +8.681[1] mas/yr
Parallax (π)10.8432 ± 0.3325[1] mas
Distance301 ± 9 ly
(92 ± 3 pc)
Absolute magnitude (MV)0.88[6]
Details
Mass2.01[2] M
Radius9.86+0.23
−0.25
[1] R
Luminosity54.7±1.9[1] L
Surface gravity (log g)2.860[7] cgs
Temperature4,944±79[2] K
Metallicity [Fe/H]−0.11[7] dex
Rotational velocity (v sin i)1.6[8] km/s
Age1.98[2] Gyr
Other designations
30 Aqr, BD−07°5688, HD 209396, HIP 108868, HR 8401, SAO 145836[9]
Database references
SIMBADdata

30 Aquarii is a single[10] star located about 301 light years away from the Sun in the zodiac constellation of Aquarius. 30 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.56.[2] The star is moving further from the Earth with a heliocentric radial velocity of 40 km/s.[2]

This object is an aging G-type giant star[6][5] with a stellar classification of G8 III,[4] although Houk and Swift (1999) found a class of K1 IV.[3] It is a red clump giant,[6] which indicates it is on the horizontal branch and is generating energy through helium fusion at its core. The star is nearly two[2] billion years old with a leisurely rotation rate, showing a projected rotational velocity of 1.6 km/s.[8] It has double[2] the mass of the Sun and has expanded to ten[1] times the Sun's radius. The star is radiating 55[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,944 K.[2]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 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.
  2. 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode2015AJ....150...88L. 
  3. 3.0 3.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey 5, Bibcode1999MSS...C05....0H. 
  4. 4.0 4.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  5. 5.0 5.1 Henry, Gregory W. et al. (September 2000), "Photometric Variability in a Sample of 187 G and K Giants", The Astrophysical Journal Supplement Series 130 (1): 201–225, doi:10.1086/317346, Bibcode2000ApJS..130..201H. 
  6. 6.0 6.1 6.2 Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal 539 (2): 732–741, doi:10.1086/309278, Bibcode2000ApJ...539..732A. 
  7. 7.0 7.1 McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series 74: 1075–1128, doi:10.1086/191527, Bibcode1990ApJS...74.1075M. 
  8. 8.0 8.1 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, doi:10.1088/0004-6256/135/1/209, Bibcode2008AJ....135..209M 
  9. "30 Aqr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=30+Aqr. 
  10. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 

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