20 Aquilae

20 Aquilae

A light curve for 20 Aquilae, plotted from Hipparcos data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 12m 40.71201s[2]
Declination −07° 56′ 22.2650″[2]
Apparent magnitude (V) 5.362[3]
Characteristics
Spectral type B3 V,[4] B3 IV,[5] or B2/3 II[6]
B−V color index +0.088[3]
Astrometry
Radial velocity (Rv)−23.0±0.7[7] km/s
Proper motion (μ) RA: +14.040[2] mas/yr
Dec.: –6.814[2] mas/yr
Parallax (π)3.5374 ± 0.1720 mas[2]
Distance920 ± 40 ly
(280 ± 10 pc)
Absolute magnitude (MV)−2.02[8]
Details
Mass8.6±0.2[9] M☉
Luminosity (bolometric)7,284[3] L☉
Temperature18,700[3] K
Rotational velocity (v sin i)133±6[4] km/s
Age27.9±4.1[9] Myr
Other designations
20 Aql, NSV 11808, BD−08° 4887, GC 26461, HD 179406, HIP 94385, HR 7279, SAO 143134[10]
Database references
SIMBADdata

20 Aquilae, abbreviated 20 Aql, is an irregular variable[11] star in the equatorial constellation of Aquila. 20 Aquilae is its Flamsteed designation. It ranges in magnitude from a peak of 5.33 down to 5.36, which is bright enough for the star to be visible to the naked eye.[12] The estimated distance to this star is around 920 light years, based upon an annual parallax shift of 3.5 mas.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −23 km/s.[7]

There has been some disagreement over the stellar classification of this star. Buscombe (1962) listed a class of B3 IV,[5] which suggests a B-type subgiant star that has exhausted the hydrogen at its core and is expanding off the main sequence. Lesh (1968)[13] and Braganca et al. (2012)[4] matched a B-type main sequence star with a class of B3 V. However, Houk and Swift (1999) found a class of B2/3 II,[6] indicating this is an evolved bright giant.

The star is about 28[9] million years old with a high rate of spin, showing a projected rotational velocity of 133 km/s.[4] It has 8.6[9] times the mass of the Sun and is radiating 7,284 times the Sun's luminosity from its photosphere at an effective temperature of 18,700 K.[3]

  1. ^ Cite error: The named reference HipDataAccess was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Hohle2010 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Braganca2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Buscombe1962 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Houk1999 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference Tetzlaff2011 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference lefevre2009 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Lesh1968 was invoked but never defined (see the help page).