104 Aquarii

This article is about A2 Aquarii. For A1 Aquarii, see 103 Aquarii. For all stars with the same Bayer designation, see A Aquarii.
104 Aquarii
Observation data
Epoch J2000      Equinox J2000
Constellation Aquarius
A
Right ascension 23h 41m 45.80579s[1]
Declination –17° 48′ 59.5175″[1]
Apparent magnitude (V) 4.83[2]
B
Right ascension 23h 41m 46.37788s[1]
Declination –17° 47′ 00.7237″[1]
Apparent magnitude (V) 8.54[2]
Characteristics
A
Spectral type G2 Ib/II[3]
U−B color index +0.49[2]
B−V color index +0.82[2]
B
Spectral type A5/7 (V)[3]
B−V color index +0.15[2]
Astrometry
A
Radial velocity (Rv)+6.52±0.15[4] km/s
Proper motion (μ) RA: +14.872[1] mas/yr
Dec.: +0.862[1] mas/yr
Parallax (π)4.5774 ± 0.1882 mas[1]
Distance710 ± 30 ly
(218 ± 9 pc)
Absolute magnitude (MV)–2.49[4]
B
Proper motion (μ) RA: –27.214[1] mas/yr
Dec.: –28.539[1] mas/yr
Parallax (π)3.2221 ± 0.0487 mas[1]
Distance1,010 ± 20 ly
(310 ± 5 pc)
Details
104 Aqr A
Mass4.23[5] M☉
Radius31.9±2.3[4] R☉
Luminosity447[5] L☉
Surface gravity (log g)2.20[4] cgs
Temperature5,444±14[4] K
Metallicity [Fe/H]+0.05[6] dex
Rotational velocity (v sin i)15[7] km/s
Age135[5] Myr
Other designations
HR 8982, SAO 165836.[8]
A: BD −18 6358, HD 222574, HIP 116901
B: BD −18 6359, HD 222561, HIP 116904
Database references
SIMBADdata
B

104 Aquarii (abbreviated 104 Aqr) is a star in the equatorial constellation of Aquarius. 104 Aquarii is the Flamsteed designation, although it also bears the Bayer designation A2 Aquarii. Based on an annual parallax shift of only 3.89 ± 0.25 milliarcseconds, the distance to this star is about 840 light-years (260 parsecs).[9] At that range, the brightness of the star in the V-band is reduced by 0.10 magnitudes as a result of extinction caused by intervening gas and dust.[5]

This is a double star and possible binary system.[10] The primary component has a stellar classification of G2 Ib/II,[3] which places it on the borderline between the bright giant and lower luminosity supergiant stars. It has passed the first dredge-up and may be undergoing Cepheid-like pulsations.[4] With more than four times the mass of the Sun,[5] this is an evolved star that has reached its current stage after only 135 million years.[5] It has expanded to around 51–88[11] times the Sun's radius and is radiating 447–fold[5] the luminosity of the Sun. This energy is being emitted from its outer atmosphere at an effective temperature of 5,478 K,[6] giving it the golden-hued glow of a G-type star.[12] It is a suspected variable star.[13]

The companion is a magnitude 7.9 star with an angular separation of 120.1 arcseconds from the primary.[10]

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  2. ^ a b c d e Cite error: The named reference ducati was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference houk1988 was invoked but never defined (see the help page).
  4. ^ a b c d e f Cite error: The named reference Usenko2015 was invoked but never defined (see the help page).
  5. ^ a b c d e f g Cite error: The named reference pasj60_4_781 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference apj241_218 was invoked but never defined (see the help page).
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  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference mnras389_2_869 was invoked but never defined (see the help page).
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  12. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference ibvs4322_1 was invoked but never defined (see the help page).