Phi Aquilae

Phi Aquilae
Location of φ Aquilae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Aquila
Right ascension 19h 56m 14.25183s[1]
Declination +11° 25′ 25.3931″[1]
Apparent magnitude (V) +5.28[2]
Characteristics
Spectral type A1 IV[3]
U−B color index –0.02[2]
B−V color index +0.00[2]
Astrometry
Radial velocity (Rv)–27.2[4] km/s
Proper motion (μ) RA: +32.826[1] mas/yr
Dec.: +6.162[1] mas/yr
Parallax (π)14.1980 ± 0.1579 mas
Distance230 ± 3 ly
(70.4 ± 0.8 pc)
Absolute magnitude (MV)+1.14[5]
Orbit[6]
Period (P)3.32068 days
Eccentricity (e)0.025
Periastron epoch (T)JD 2423210.628
Argument of periastron (ω)
(secondary)		43°
Semi-amplitude (K1)
(primary)		37.2 km/s
Details
A
Mass2.39[7] M☉
Radius1.8–2.5[8] R☉
Luminosity34[5] L☉
Surface gravity (log g)4.30[9] cgs
Temperature9,509[9] K
Metallicity [Fe/H]+0.47[9] dex
Rotational velocity (v sin i)27[10] km/s
Age280[7] Myr
B
Mass0.40[7] M☉
Other designations
φ Aql, 61 Aql, BD+11° 4055, FK5 3590, HD 188728, HIP 98103, HR 7610, SAO 105438[11]
Database references
SIMBADdata

Phi Aquilae, Latinized from φ Aquilae, is the Bayer designation of a binary star[12] system in the equatorial constellation of Aquila. It has an apparent visual magnitude of +5.28[2] and is visible to the naked eye. With an annual parallax shift of 14.198 mas,[1] this star is located at a distance of approximately 230 light-years (71 parsecs) from Earth. It is drifting closer with a radial velocity of –27 km/s.[4] Based on its motion through space, this system is considered a possible member of the nearby Argus association of co-moving stars, although it may be too old.[13]

Phi Aquilae is a single-lined spectroscopic binary with an orbital period of 3.32068 days.[6] The pair have a projected separation of 190.4 AU as of 2008.[7] The primary component is a subgiant star with a stellar classification of A1 IV.[3] The star is around 280[7] million years old and is spinning with a projected rotational velocity of 27.[10] It has 2.39[7] times the mass of the Sun and somewhere in the range of 1.8–2.5[8] times the Sun's radius. The outer atmosphere has an effective temperature of 9,509 K,[9] giving it the white-hued appearance of an A-type star.[14] It is radiating 34[5] times the luminosity of the Sun.

The orbiting companion may be the source of the X-ray emission from this system, as stars similar to the primary component do not generally produce detectable levels of X-rays.[15] It has 40% of the mass of the Sun.[7]

  1. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference aaass52_131 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference aj74_375 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference gcrv1953 was invoked but never defined (see the help page).
  5. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference aj76_544 was invoked but never defined (see the help page).
  7. ^ a b c d e f g Cite error: The named reference De_Rosa_et_al_2014 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference aaa367_521 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference aaa515_A11 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference aaa463_2_671 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference mnras389_2_869 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Zuckerman2019 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference mnras415_1_854 was invoked but never defined (see the help page).