Delta Aquarii

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Template:Short description

δ Aquarii
Template:Location mark
Location of δ Aquarii (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius[1]
Right ascension Template:RA[2]
Declination Template:DEC[2]
Apparent magnitude (V) 3.28[3]
Characteristics
Spectral type A3Vp[4]
U−B Template:Engvar +0.08[5]
B−V Template:Engvar +0.05[5]
Astrometry
Radial velocity (Rv)+17.4±0.9[6] km/s
Proper motion (μ) RA: −38.904 mas/yr[7]
Dec.: −33.027 mas/yr[7]
Parallax (π)28.7936±0.7289 mas[7]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−0.17[1]
Details
Mass3.19[8] Template:Solar mass
Radius4.16[8] Template:Solar radius
Luminosity100[8] Template:Solar luminosity
Surface gravity (log g)3.73[9] cgs
Temperature8,650[10] K
Metallicity [Fe/H]–0.21[11] dex
Rotational velocity (v sin i)81[12] km/s
Age300[13] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[14]
Database references
SIMBADdata

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Delta Aquarii is a binary star system in the constellation of Aquarius. Its identifier is a Bayer designation that is Latinized from δ Aquarii, and abbreviated Delta Aqr or δ Aqr, respectively. This system has the official name Skat, pronounced Template:IPAc-en.[15] It is the third-brightest star in Aquarius with an apparent visual magnitude of 3.3,[16] and is readily visible to the naked eye at night. The distance to this system is about Template:Convert based upon parallax measurements. It is drifting further away from the Sun with a radial velocity of +17 km/s.[6]

Nomenclature

δ Aquarii (Latinised to Delta Aquarii) is the star's Bayer designation. It also has the Flamsteed designation 76 Aquarii.

It bore the traditional name Skat (also rendered Scheat, Seat, Sheat, etc., which was erroneously applied to Beta Pegasi in late medieval times), from the Arabic الساق al-sāq "shin".[17]

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[18] to catalogue and standardize proper names for stars. The WGSN approved the name Skat for this star on 21 August 2016, and it is now so included in the List of IAU-approved Star Names.[15]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Palace Guard, refers to an asterism consisting of Delta Aquarii, 29 Aquarii, 35 Aquarii, 41 Aquarii, 47 Aquarii, 49 Aquarii, Lambda Piscis Austrini, HD 212448, Epsilon Piscis Austrini, 21 Piscis Austrini, 20 Piscis Austrini, Upsilon Aquarii, 68 Aquarii, 66 Aquarii, 61 Aquarii, 53 Aquarii, 50 Aquarii, 56 Aquarii, 45 Aquarii, 58 Aquarii, 64 Aquarii, 65 Aquarii, 70 Aquarii, 74 Aquarii, Tau2 Aquarii, Tau1 Aquarii, 77 Aquarii, 88 Aquarii, 89 Aquarii, 86 Aquarii, 101 Aquarii, 100 Aquarii, 99 Aquarii, 98 Aquarii, 97 Aquarii, 94 Aquarii, Psi3Aquarii, Psi2Aquarii, Psi1Aquarii, 87 Aquarii, 85 Aquarii, 83 Aquarii, Chi Aquarii, Omega1 Aquarii and Omega2 Aquarii. Consequently, the Chinese name for Delta Aquarii itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[19]

Properties

The spectrum of Delta Aquarii matches a stellar classification of A3 Vp, indicating this is a chemically peculiar A-type main-sequence star that is generating energy through the nuclear fusion of hydrogen at its core. This star has three times the Sun's mass and a radius 4.16 times as large. It is radiating 100 times the luminosity of the Sun[8] from its outer atmosphere at an effective temperature of around 9,000 K.[20] This heat gives it the characteristic white-hued glow of an A-type star.[21] It has a relatively high rate of rotation, with a projected rotational velocity of 81 km s−1.[12]

Delta Aquarii does not display a strong signal of excess infrared emission that might indicate the presence of circumstellar matter.[22] It is a probable stream star member of the Ursa Major Moving Group,[23] which has an estimated age of 500 million years.[24]

An analysis of Hipparcos data strongly suggested a close companion object. An orbit was derived with a 483-day period, an eccentricity of 0.12, and an inclination of 41°. When Delta Aquarii was first examined for a companion, none was found. Any possible companion beyond Template:Val was constrained to be less than Template:Solar mass.[13] Infrared interferometric observations did subsequently find a companion in 2017: a likely G5 main sequence star around Template:Val from the primary.[25]

References

Template:Reflist

External links

Template:Stars of Aquarius

  1. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Anderson2012
  2. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aaa474_2_653
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named ducati
  4. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named abt
  5. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named hr
  6. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Gontcharov_2006
  7. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named dr2
  8. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named gaspar
  9. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named david
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named zorec
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named takeda
  12. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aaa463_2_671
  13. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aaa523_A73
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named SIMBAD
  15. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named IAU-LSN
  16. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aaass22_9
  17. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Kunitzsch
  18. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named WGSN
  19. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 7 日 Template:Webarchive
  20. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aaa294_2_536
  21. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named csiro
  22. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named apj653_1_675
  23. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aj125_4_1980
  24. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aaa442_2_563
  25. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named borgniet
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