FF Aquilae

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FF Aquilae
Aquila constellation map.svg
Red circle.svg
Location of FF Aquilae (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Aquila
Right ascension 18h 58m 14.74830s [1]
Declination +17° 21 39.2976 [1]
Apparent magnitude  (V)5.18 - 5.51 [2]
Characteristics
Spectral type F6Ib [3]
U−B color index 0.43 [4]
B−V color index 0.8 [4]
Variable type δ Cep [2]
Astrometry
Radial velocity (Rv)−15.47±1.61 [1]  km/s
Proper motion (μ)RA: −1.151 [1]   mas/yr
Dec.: −9.823 [1]   mas/yr
Parallax (π)1.9057 ± 0.0712  mas [1]
Distance 1,710 ± 60  ly
(520 ± 20  pc)
Absolute magnitude  (MV)−3.4 [5]
Details
Mass 3.2 [6]   M
Radius 39 [5]   R
Luminosity 2,238 [7]   L
Surface gravity (log g)1.28 [8]   cgs
Temperature 6,195 [5]   K
Metallicity [Fe/H]+0.04 [9]   dex
Rotational velocity (v sin i)10.0 [10]  km/s
Age 60 [9]   Myr
Other designations
FF Aql, HD 176155, HIP 93124, BD+17°3799, HR 7165, SAO 104296.
Database references
SIMBAD data

FF Aquilae is a classical Cepheid variable star located in the constellation Aquila, close to the border with Hercules. It ranges from apparent magnitude 5.18 to 5.51 over a period of 4.47 days, [2] meaning it is faintly visible to the unaided eye in rural or suburban settings. [11]

The visual band light curve of FF Aquilae, adapted from Kiss (1998) FFAqlLightCurve.png
The visual band light curve of FF Aquilae, adapted from Kiss (1998)

Originally known as HR 7165, it was noted to be variable by Charles Morse Huffer in August 1927, who observed its Cepheid pattern. It then received the variable star designation FF Aquilae. [13] Analysis of its brightness over 122 years shows that its period is increasing by 0.072±0.011 seconds per year. [14] It is a small amplitude classical Cepheid, and as such is expected to be a supergiant near the red edge of the instability strip. [2]

A yellow supergiant, FF Aqlilae pulsates with varying temperature, diameter, and luminosity. [5] It has been estimated to be 1,710 ± 60 light-years (520 ± 20 parsecs ) distant from Earth by extrapolating from its angular diameter and estimated radius. [5]

FF Aquilae is a possible quadruple star system. Analysis of its spectrum shows that it is a spectroscopic binary system with the fainter companion calculated to be a main sequence star of spectral type A9V to F3V, orbiting every 3.92 years. A third star, revealed by speckle interferometry, is likely to be a cooler star that has evolved off the main sequence. [15] A fourth star, that is of magnitude 11.4 and located 6 arcseconds away, is a somewhat evolved star slightly hotter, larger, and more luminous than the Sun. [16] Several studies found it unlikely to be a member of the system, [6] [17] although Gaia Data Release 3 finds it to be at a similar distance and with a similar proper motion. [16]

Related Research Articles

<span class="mw-page-title-main">V1494 Aquilae</span> Nova seen in 1999 in the constellation of Aquila

V1494 Aquilae or Nova Aquilae 1999 b was a nova which occurred during 1999 in the constellation Aquila and reached a brightness of magnitude 3.9 on 2 December 1999. making it easily visible to the naked eye. The nova was discovered with 14×100 binoculars by Alfredo Pereira of Cabo da Roca, Portugal at 18:50 UT on 1 December 1999, when it had a visual magnitude of 6.0.

<span class="mw-page-title-main">Eta Aquilae</span> Multiple star in the constellation Aquila

Eta Aquilae is a multiple star in the equatorial constellation of Aquila, the eagle. It was once part of the former constellation Antinous. Its apparent visual magnitude varies between 3.49 and 4.3, making it one of the brighter members of Aquila. Based upon parallax measurements made by the Gaia spacecraft on its third data release (DR3), this star is located at a distance of roughly 272 parsecs. The primary component is a Classical Cepheid variable.

<span class="mw-page-title-main">W Sagittarii</span> Star in the constellation Sagittarius

W Sagittarii is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star.

<span class="mw-page-title-main">X Sagittarii</span> Variable star and possible binary star system in the constellation Sagittarius

X Sagittarii is a variable star and candidate binary star system in the southern constellation of Sagittarius, near the western constellation boundary with Ophiuchus. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude that fluctuates around 4.54. The star is located at a distance of approximately 950 light years from the Sun based on parallax, and is drifting closer with a radial velocity of −10 km/s. The star has an absolute magnitude of around −2.85.

<span class="mw-page-title-main">21 Aquilae</span> Star in the constellation Aquila

21 Aquilae is a solitary variable star in the equatorial constellation of Aquila. It has the variable star designation V1288 Aql; 21 Aquilae is its Flamsteed designation. This object is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of about 5.1. The star is located at a distance of around 680 light-years from Earth, give or take a 20 light-year margin of error. It is moving closer to the Earth with a heliocentric radial velocity of –5 km/s.

<span class="mw-page-title-main">28 Aquilae</span> Star in the constellation Aquila

28 Aquilae, abbreviated 28 Aql, is a star in the equatorial constellation of Aquila. 28 Aquilae is its Flamsteed designation though it also bears the Bayer designation A Aquilae, and the variable star designation V1208 Aquilae. It has an apparent visual magnitude is 5.5, making this a faint star that requires dark suburban skies to view. The annual parallax shift of 9.6 mas means this star is located at a distance of approximately 340 light-years from Earth.

<span class="mw-page-title-main">10 Aquilae</span> Star in the constellation Aquila

10 Aquilae is a star in the equatorial constellation of Aquila. 10 Aquilae is the Flamsteed designation. It has an apparent visual magnitude of 5.9 and thus is a faint star that is just visible to the naked eye in dark skies. The brightness of this star is diminished by 0.17 in visual magnitude from extinction caused by interstellar gas and dust. Based on an annual parallax shift of 13.45 mas, the distance to this star is around 240 light-years.

<span class="mw-page-title-main">RT Aurigae</span> Star in the constellation Auriga

RT Aurigae is a yellow supergiant variable star in the constellation Auriga, about 1,500 light years from Earth.

<span class="mw-page-title-main">Y Carinae</span> Star in the constellation Carina

Y Carinae is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.

<span class="mw-page-title-main">V Centauri</span> Variable star in the constellation Centaurus

V Centauri is a Classical Cepheid variable, a type of variable star, in the constellation Centaurus. It is approximately 2,350 light-years away based on parallax.

<span class="mw-page-title-main">RS Puppis</span> Variable star in the constellation Puppis

RS Puppis is a Cepheid variable star around 6,000 ly away in the constellation of Puppis. It is one of the biggest and brightest known Cepheids in the Milky Way galaxy and has one of the longest periods for this class of star at 41.5 days.

<span class="mw-page-title-main">U Aquilae</span> Variable binary star system in the constellation Aquila

U Aquilae is a binary star system in the constellation Aquila, Located approximately 614 parsecs (2,000 ly) away from Earth.

<span class="mw-page-title-main">V1472 Aquilae</span> Binary star system in the constellation Aquila

V1472 Aquilae is a triple star system in the equatorial constellation of Aquila. It is a variable star that ranges in brightness from 6.36 down to 6.60. The system is located at a distance of approximately 780 light years from the Sun based on parallax. It is a high-velocity star system with a radial velocity of −112 km/s.

<span class="mw-page-title-main">TT Aquilae</span> Star in the constellation Aquila

TT Aquilae is a Classical Cepheid variable star in the constellation Aquila.

<span class="mw-page-title-main">Classical Cepheid variable</span>

Classical Cepheids are a type of Cepheid variable star. They are young, population I variable stars that exhibit regular radial pulsations with periods of a few days to a few weeks and visual amplitudes ranging from a few tenths of a magnitude up to about 2 magnitudes. Classical Cepheids are also known as Population I Cepheids, Type I Cepheids, and Delta Cepheid variables.

<span class="mw-page-title-main">AX Circini</span> Binary star system in the constellation Circinus

AX Circini is a binary star system in the southern constellation of Circinus. It has a nominal magnitude of 5.91, which is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 1.7 mas, it is located roughly 1,900 light-years from the Earth. The system is moving closer with a heliocentric radial velocity of −21 km/s.

<span class="mw-page-title-main">T Vulpeculae</span> Variable star in the constellation Vulpecula

T Vulpeculae is a possible binary star system in the northern constellation of Vulpecula, near the star Zeta Cygni, close to the pair 31 Vulpeculae and 32 Vulpeculae. It is visible to the naked eye with an apparent visual magnitude that ranges around 5.75. The distance to this system is around 1,900 light years, as determined from its annual parallax shift of 1.67 mas.

<span class="mw-page-title-main">U Vulpeculae</span> Variable star in the constellation Vulpecula

U Vulpeculae is a variable and binary star in the constellation Vulpecula.

<span class="mw-page-title-main">W Aquilae</span> Variable star in the constellation Aquila

W Aquilae is a variable star in the constellation of Aquila. It is a type of evolved star known as an S-type star. Due to its relatively close distance of 1,200 light-years and equatorial location, it is easy to observe and heavily studied.

<span class="mw-page-title-main">X Cygni</span> Variable star in the constellation Cygnus

X Cygni is a variable star in the northern constellation of Cygnus, abbreviated X Cyg. This is a Delta Cephei variable that ranges in brightness from an apparent visual magnitude of 5.85 down to 6.91 with a period of 16.386332 days. At it brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 628 light years based on parallax measurements. It is drifting further away with a radial velocity of 8.1 km/s. This star is a likely member of the open cluster Ruprecht 173.

References

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