21 Aquarii

Last updated
21 Aquarii
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Aquarius
Right ascension 21h 25m 16.95755s [1]
Declination −03° 33 24.2964 [1]
Apparent magnitude  (V)5.48 [2]
Characteristics
Spectral type K4III [3]
B−V color index 1.451±0.011 [2]
Astrometry
Radial velocity (Rv)−24.5±2 [4]  km/s
Proper motion (μ)RA: −12.061 [1]   mas/yr
Dec.: −69.973 [1]   mas/yr
Parallax (π)7.8747 ± 0.2182  mas [1]
Distance 410 ± 10  ly
(127 ± 4  pc)
Absolute magnitude  (MV)0.11 [2]
Details
Radius 28.01+1.09
−2.12
[1]   R
Luminosity 203.4±6.4 [1]   L
Surface gravity (log g)1.79 [5]   cgs
Temperature 4119+165
−78
[1]   K
Metallicity [Fe/H]−0.08 [5]   dex
Other designations
BD−04°5446, FK5  3708, HD  203926, HIP  105767, HR  8199, SAO  145384
Database references
SIMBAD data

21 Aquarii is a single [6] star in the zodiac constellation of Aquarius. 21 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.49. [2] This object is a member of the HR 1614 moving group, [7] and is moving closer to the Earth with a heliocentric radial velocity of −24.5 km/s. [4]

This object is an evolved giant star with a stellar classification of K4 III. [3] As a result of having exhausted the hydrogen at its core, it has expanded to 27 [1] times the radius of the Sun. The star is radiating 203 [1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,120 K. [1]

Related Research Articles

<span class="mw-page-title-main">86 Aquarii</span> Binary star in the constellation Aquarius

86 Aquarii is a binary star system in the equatorial constellation of Aquarius. 86 Aquarii is the Flamsteed designation, though it also bears the Bayer designation c1 Aquarii. It is faint but visible to the naked eye with an apparent visual magnitude of +4.47. Based upon parallax measurements, the distance to this star is about 220 light-years.

68 Aquarii is a single star located 270 light years away from the Sun in the zodiac constellation of Aquarius. 68 Aquarii is its Flamsteed designation, though it also bears the Bayer designation of g2 Aquarii. It is visible to the naked eye as a dim, yellow-hued star with an apparent visual magnitude of 5.24. The object is moving further from the Earth with a heliocentric radial velocity of +24.5 km/s.

42 Aquarii is a single star located 447 light years away from the Sun in the zodiac constellation of Aquarius. 42 Aquarii is its Flamsteed designation. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.34. This object is moving further from the Sun with a heliocentric radial velocity of around +13 km/s.

103 Aquarii is a single star in the equatorial constellation of Aquarius. 103 Aquarii is the Flamsteed designation, although it also bears the Bayer designation A1 Aquarii. It is faint but visible to the naked eye as an orange hued star with an apparent visual magnitude of 5.34. Based upon an annual parallax shift of 4.69 mas, the distance to this star is around 700 light-years (210 parsecs). It is moving away from the Earth with a heliocentric radial velocity of +25 km/s.

7 Aquarii, abbreviated 7 Aqr, is a binary star system in the zodiac constellation of Aquarius. 7 Aquarii is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 5.5; the brighter component is baseline magnitude 5.62 while the faint secondary is magnitude 11.4. As of 2002, the pair had an angular separation of 2.10″ along a position angle of 165°. The distance to this system, based upon an annual parallax shift of 4.9 mas, is around 660 light years. It is moving closer to the Earth with a heliocentric radial velocity of −32 km/s.

12 Aquarii is a triple star system in the zodiac constellation of Aquarius. 12 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim star with an apparent visual magnitude of 5.67. Parallax measurements by Hipparcos puts it at a distance of some 500 light-years, or 150 parsecs away. The system is moving further from the Earth with a heliocentric radial velocity of +1.1 km/s.

77 Aquarii is a single star located 135 light years away from the Sun in the equatorial constellation of Aquarius. 77 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim star with a baseline apparent visual magnitude of 5.55. The star is moving closer to the Earth with a heliocentric radial velocity of −35 km/s.

5 Aquarii is a single star in the zodiac constellation of Aquarius, located about 830 light years away from the Sun, based on parallax. 5 Aquarii is the Flamsteed designation. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.55. This object is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.

30 Aquarii is a single 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. The star is moving further from the Earth with a heliocentric radial velocity of 40 km/s.

26 Aquarii is a single star located approximately 960 light years away from the Sun in the zodiac constellation of Aquarius. 26 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.66. This object is moving away from the Earth with a heliocentric radial velocity of +8 km/s.

44 Aquarii is a single star located 336 light years away from the Sun in the equatorial constellation of Aquarius. 44 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-hued star with an apparent visual magnitude of 5.75. This body is moving away from the Earth with a heliocentric radial velocity of +7.4 km/s.

35 Aquarii, also known by its Flamsteed designation, is a single star located approximately 2,200 light years away from the Sun in the zodiac constellation of Aquarius. It is visible to the naked eye as a faint, blue-white star with an apparent visual magnitude of 5.80. This object is moving closer to Earth with a heliocentric radial velocity of −7 km/s, and is suspected to be a runaway star, potentially ejected from an open cluster due to a binary–binary interaction.

60 Aquarii is a star located 375 light years away from the Sun in the equatorial constellation of Aquarius. 60 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-hued star with an apparent visual magnitude of 5.89. The star is moving closer to the Earth with a heliocentric radial velocity of –8 km/s.

28 Aquarii is a single star located about 560 light years away from the Sun in the zodiac constellation of Aquarius. 28 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.6. This object is moving further from the Earth with a heliocentric radial velocity of +8.1 km/s.

<span class="mw-page-title-main">Lambda Piscis Austrini</span> Star in the constellation Piscis Austrinus

Lambda Piscis Austrini, Latinized from λ Piscis Austrini, is a solitary star in the southern constellation of Piscis Austrinus. It has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of +5.42. Based upon an annual parallax shift of 6.51 mas as measured from Earth, it is located around 500 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.16 due to interstellar dust.

HD 56618 is a single star in the southern constellation of Canis Major. It is a red-hued star that is faintly visible to the naked eye with an apparent visual magnitude of 4.66. This object is located at a distance of approximately 390 light years from the Sun based on parallax measurements. It is drifting further away with a radial velocity of +41.5 km/s, having come to within 203 light-years some 2.2 million years ago. Olin J. Eggen listed it as a probable member of the Hyades supercluster.

45 Eridani is a single star located around 700 light years away from the Sun in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.91. This body is moving away from the Earth with a heliocentric radial velocity of +15 km/s.

6 Hydrae is a single star in the equatorial constellation of Hydra, located 373 light-years away from the Sun. It has the Bayer designation a Hydrae; 6 Hydrae is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.98. It is moving closer to the Earth with a heliocentric radial velocity of −8 km/s. Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.

κ Gruis, Latinised as Kappa Gruis, is a solitary star in the southern constellation of Grus. With an apparent magnitude of 5.37, it is visible to the naked eye as a dim, orange-hued point. The distance to this system, as determined from an annual parallax shift of 8.87 mas as seen from the Earth, is roughly 368 light years. It is drifting further away with a heliocentric radial velocity of +18 km/s. It is a member of the Arcturus moving group.

11 Serpentis is a single star in the constellation of Serpens, located 271 light years away from the Sun. It has the Bayer designation A1 Serpentis, 11 Serpentis is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.497. It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 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.
  2. 1 2 3 4 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 .
  3. 1 2 Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W.
  5. 1 2 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. Bibcode:1990ApJS...74.1075M. doi: 10.1086/191527 .
  6. 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. arXiv: 0806.2878 . Bibcode:2008MNRAS.389..869E. doi: 10.1111/j.1365-2966.2008.13596.x . S2CID   14878976.
  7. Eggen, Olin J.; Iben, Icko Jr. (April 1991), "First giant branch and asymptotic giant branch stars in nearby aggregates", Astronomical Journal, 101: 1377–1407, Bibcode:1991AJ....101.1377E, doi:10.1086/115773 .