27 Aquilae

27 Aquilae
Location of 27 Aquilae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Aquila
Right ascension 19h 20m 35.68321s[1]
Declination −00° 53′ 31.8067″[1]
Apparent magnitude (V) 5.49[2]
Characteristics
Spectral type B9 III[3]
U−B color index −0.23[2]
B−V color index −0.04[2]
Astrometry
Radial velocity (Rv)−27[4] km/s
Proper motion (μ) RA: 5.42[1] mas/yr
Dec.: 2.83[1] mas/yr
Parallax (π)7.45 ± 0.28 mas[1]
Distance440 ± 20 ly
(134 ± 5 pc)
Absolute bolometric
magnitude (Mbol)		2.04–2.27[5]
Details
Surface gravity (log g)3.61 ± 0.50[6] cgs
Temperature11,500[6] K
Rotational velocity (v sin i)55[7] km/s
Other designations
BD−01° 3716, GC 26673, HD 181440, HIP 95073, HR 7336, PPM 180629, SAO 143292.[8]
Database references
SIMBADdata

27 Aquilae (abbreviated 27 Aql) is a star in the equatorial constellation of Aquila. 27 Aquilae is its Flamsteed designation though it also bears the Bayer designation d Aquilae. It has an apparent visual magnitude of 5.49,[2] which is faintly visible to the naked eye. Based upon parallax measurements made during the Hipparcos mission, this star is at a distance of 440 light-years (130 parsecs) from Earth, give or take a 20 light-year margin of error.[1] At this distance, the brightness of the star is diminished from extinction caused by interstellar gas and dust.[5]

The spectrum of 27 Aquilae fits a stellar classification of B9 III,[3] with the luminosity class of III typically indicating this is an evolved giant star. As it lies within the field of view of the CoRoT satellite,[6] close observation have been made of its luminosity. The star shows a multiperiodic variability with at least six pulsation frequencies discovered.[9] It has a high rate of rotation with a projected rotational velocity of 55 km/s.[7] The outer atmosphere is radiating energy into space at an effective temperature of around 11,500 K,[6] giving it the blue-white hue of a B-type star.

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