74 Aquarii

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74 Aquarii
HIAqrLightCurve.png
A light curve for HI Aquarii, plotted from TESS data [1]
Observation data
Epoch J2000       Equinox J2000
Constellation Aquarius
Right ascension 22h 53m 28.70492s [2]
Declination −11° 36′ 59.4532″ [2]
Apparent magnitude  (V)5.8 [3]
Characteristics
Spectral type B8IV/V [4] (B9pHgMn) [3] )
U−B color index −0.245 [5]
B−V color index −0.082 [5]
Variable type a2 CVn [3]
Astrometry
Proper motion (μ)RA: +21.539 [2] mas/yr
Dec.: +2.282 [2] mas/yr
Parallax (π)5.5008±0.6556  mas [2]
Distance approx. 590  ly
(approx. 180  pc)
Absolute magnitude  (MV)−1.19 [6]
Orbit [7]
Primary74 Aquarii A
Companion74 Aquarii B
Period (P)9.479±0.044 yr
Semi-major axis (a)0.0460±0.0061″
Eccentricity (e)0.862±0.029
Inclination (i)29.8±17.4°
Longitude of the node (Ω)40.9±20.3°
Periastron epoch (T)2010.039±0.134
Argument of periastron (ω)
(secondary)		70.7±16.1°
Orbit [8]
Primary74 Aquarii Aa
Companion74 Aquarii Ab
Period (P)3.429616±0.000004 d
Eccentricity (e)0.05±0.02
Periastron epoch (T)2452909.150±0.007  JD
Argument of periastron (ω)
(secondary)		86.5±0.8°
Semi-amplitude (K1)
(primary)		95±2 km/s
Semi-amplitude (K2)
(secondary)		113±2 km/s
Details
Aa
Mass 2.72 [9]   M☉
Rotational velocity (v sin i)20 [10]  km/s
Ab
Mass 2.53 [9]   M☉
B
Mass 3.11 [9]   M☉
Other designations
HI Aqr, BD−12 6371, HD 216494, HIP 113031, HR  8704, SAO 165359 [11]
Database references
SIMBAD data

74 Aquarii (abbreviated 74 Aqr) is a triple star [12] system in the constellation of Aquarius. 74 Aquarii is its Flamsteed designation and it also bears the variable star designation HI Aquarii. The combined apparent visual magnitude is 5.8, [5] although it is very slightly variable, [3] and it is located at a distance of 590 light-years (180 parsecs ) from Earth.

Contents

Jean Manfroid and Gautier Mathys reported that 74 Aquarii is a variable star in 1985. [13] Based on that result it was given its variable star designation in 1987. [14]

Visual binary

74 Aquarii is a double star with the two components separated by about 0.1″ . [15] The two components are referred to as A and B or AB and C in different publications. [7] [8] The pair form a binary with a period of 9.5 years at a typical angular separation of 0.046″, but the orbit is highly eccentric. [7] In 2010, this component was at an angular separation of 0.069  arcseconds along a position angle of 285.9°. This is equivalent to a projected separation of 13.9±2.4  AU . [12]

Spectroscopic binary

The primary star of the visual pair is a double-lined spectroscopic binary, where the presence of both components is revealed from the Doppler shift of their spectral lines, meaning 74 Aquarii is a triple system. The spectroscopic binary was discovered and the orbit calculated by Richard J. Wolff of the University of Hawaii in 1974. [16] A refined orbit was calculated in 2004 by Italian astronomers Giovanni Catanzaro and Paolo Leto. The orbital period is 3.4 days and the orbit is nearly circular. [8]

Components

The three stars have a combined spectral type of B8 or B9 and all three are thought to be similar. It is unclear whether the stars are on the main sequence, subgiants, or giant stars. [9] [17] [4] The two visual components are both chemically peculiar stars, the brighter of the two being a mercury-manganese star and the fainter an Ap/Bp star with an excess of mercury. [15] 74 Aquarii is an α2 CVn variable star, with a total amplitude of just 0.01 magnitudes, [3] and a period of 3.5892 days. [18]

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. 1 2 3 4 5 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. 1 2 3 4 5 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. Originally Published in: 2009yCat....102025S, 1: B/gcvs, Bibcode:2009yCat....102025S.
  4. 1 2 Houk, Nancy (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. 1 2 3 Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
  6. ↑ 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.
  7. 1 2 3 Tokovinin, Andrei (2017), "New Orbits Based on Speckle Interferometry at SOAR. II", The Astronomical Journal, 154 (3), 110, arXiv: 1708.01300 , Bibcode:2017AJ....154..110T, doi: 10.3847/1538-3881/aa8459 , S2CID   118429576.
  8. 1 2 3 Catanzaro, G.; Leto, P. (2004), "Orbital solutions for SB2 systems with a HgMn component", Astronomy and Astrophysics, 416 (2): 661–668, Bibcode:2004A&A...416..661C, doi: 10.1051/0004-6361:20034445 .
  9. 1 2 3 4 Tokovinin, Andrei (2018-03-01), "The Updated Multiple Star Catalog", The Astrophysical Journal Supplement Series , 235 (1): 6, arXiv: 1712.04750 , Bibcode:2018ApJS..235....6T, doi: 10.3847/1538-4365/aaa1a5 , ISSN   0067-0049, S2CID   119047709.
  10. ↑ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi: 10.1086/340590 .
  11. ↑ "* 74 Aqr", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2012-07-01.
  12. 1 2 Schöller, M.; et al. (November 2010), "Multiplicity of late-type B stars with HgMn peculiarity", Astronomy and Astrophysics, 522: A85, arXiv: 1010.3643 , Bibcode:2010A&A...522A..85S, doi:10.1051/0004-6361/201014246, S2CID   119273467.
  13. ↑ Manfroid, J.; Mathys, G. (March 1985). "New period determinations for variable CP stars". Astronomy and Astrophysics Supplement Series. 59: 429–432. Bibcode:1985A&AS...59..429M . Retrieved 19 November 2024.
  14. ↑ Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Kireeva, N.N. (August 1987). "The 68th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 3058: 1–30. Bibcode:1987IBVS.3058....1K . Retrieved 19 November 2024.
  15. 1 2 Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics, 498 (3): 961–966, Bibcode:2009A&A...498..961R, doi: 10.1051/0004-6361/200810788 .
  16. ↑ Wolff, Richard J (1974), "Orbit of the Manganese Star HR 8704", Publications of the Astronomical Society of the Pacific, 86 (510): 173–175, Bibcode:1974PASP...86..173W, doi: 10.1086/129576 .
  17. ↑ Skiff, B. A. (2014), "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009- )", VizieR On-line Data Catalog, Bibcode:2014yCat....1.2023S.
  18. ↑ "HI Aqr". The International Variable Star Index. AAVSO. Retrieved 5 December 2022.
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