Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquila |
Right ascension | 19h 15m 23.357s [1] |
Declination | −07° 02′ 50.33″ [1] |
Apparent magnitude (V) | A: 7.0 - 14.6 [2] B:14.8 [3] |
Characteristics | |
A | |
Evolutionary stage | asymptotic giant branch [4] |
Spectral type | S6/6e [4] (S3,9e - S6,9e [2] ) |
B−V color index | +2.58 [5] |
Variable type | Mira [2] |
B | |
Evolutionary stage | main sequence [4] |
Spectral type | F8/9 [4] |
Astrometry | |
Radial velocity (Rv) | −18.0 [6] km/s |
Proper motion (μ) | RA: 15.713 [1] mas/yr Dec.: 0.103 [1] mas/yr |
Parallax (π) | 2.6735 ± 0.1392 mas [1] |
Distance | 1,220 ± 60 ly (370 ± 20 pc) |
Absolute magnitude (MV) | A: −0.7 to +6.9 [3] B: +7.1 [3] |
Details | |
A | |
Mass | 1.04 - 3 [4] M☉ |
Radius | 400 [7] - 480 [8] R☉ |
Luminosity | 7,500 [9] L☉ |
Temperature | 2,300 [9] - 3,000 [7] K |
B | |
Mass | 1.04 - 1.09 [4] M☉ |
Temperature | 5,900 - 6,170 [4] K |
Other designations | |
Database references | |
SIMBAD | data |
W Aquilae (W Aql) 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 (370 pc) and equatorial location, it is easy to observe and heavily studied. [10]
W Aquilae is an S-type star with a spectral type of S3,9e to S6,9e, a red giant similar to M-type stars, but in which the dominant spectrum oxides are formed by metals of the fifth period of the periodic table. W Aquilae is also rich in the element technetium. Another feature of this class of stars is the stellar mass loss, in the case of W Aquilae is estimated at 4×10−6 solar masses per year. [11] Its effective temperature varies between 2,300 and 3,000 K and its diameter between 400 and 480 solar radii. [7] [8] It is also a very luminous star, 7,500 times more than the sun. [9]
W Aquilae is a variable whose brightness oscillates between magnitude +7.3 and +14.3 over a period of 490.43 days. In Mira variables (which are named after Mira, the prototype), this instability comes from pulsation in the stellar surface, causing changes in color and brightness. W Aquilae, a Mira variable, shows silicon monoxide maser emission. [13]
A magnitude 14.8 companion has been detected 0.47" SW of W Aquilae. This is fainter than W Aquilae at minimum and corresponds to an absolute magnitude of +7.1. Although that absolute magnitude would correspond to a K4 main sequence star, a spectrum was classified as F5 or F8. The separation between the two stars is 160 AU. [3]
A 2014 study of W Aquilae and α Centauri with the ALMA array claimed to have accidentally detected a previously-unknown Solar System object. This received widespread press coverage as a potential discovery of planet X. The paper was withdrawn without being accepted for peer-reviewed publication. [14]
Eta Aquilae is the Bayer designation for a multiple star in the equatorial constellation of Aquila, the eagle. It was once part of the former constellation Antinous. On average, this star has an apparent visual magnitude of 3.87, making it one of the brighter members of Aquila. Based upon parallax measurements made during the Hipparcos mission, this star is located at a distance of roughly 1,382 light-years, although the parallax estimate has a 44% margin of error.
Omicron Aquilae is the Bayer designation for a double star in the equatorial constellation of Aquila. The brighter component has an apparent visual magnitude of +5.11, which means it is faintly visible to the naked eye in dark suburban skies. The annual parallax shift of this star is 52.11 mas, which is equivalent to a physical distance of 62.6 light-years from Earth.
37 Aquilae, abbreviated 37 Aql, is a star in the equatorial constellation of Aquila. 37 Aquilae is its Flamsteed designation. It has an apparent visual magnitude of approximately 5.12, which is bright enough to be visible to the naked eye. The distance to 37 Aql can be estimated from its annual parallax shift of 7.4 mas, yielding a range of 444 light years. The star is moving closer to the Earth with a heliocentric radial velocity of −30 km/s, and is predicted to come to within 72 light-years in around 4.4 million years.
31 Aquilae is a star in the equatorial constellation of Aquila. 31 Aquilae is its Flamsteed designation though it also bears the Bayer designation b Aquilae. This star has an apparent visual magnitude of 5.16 and is 49.5 light years from Earth. It has no known companions.
51 Aquilae is a star in the equatorial constellation of Aquila. 51 Aquilae is its Flamsteed designation. It has an apparent visual magnitude of 5.39, which means it is faintly visible to the naked eye. Based upon an annual parallax shift of 35.88 mas, the distance to this star is around 90.9 light-years.
15 Aquilae is a star in the equatorial constellation of Aquila. 15 Aquilae is the Flamsteed designation; it also bears the Bayer designation h Aquilae. The apparent visual magnitude is 5.41, so it is faintly visible to the naked eye. An optical companion, HD 177442, is 39 arc seconds away from it The distance to 15 Aquilae can be estimated from its annual parallax shift of 11.27 mas, yielding a range of approximately 289 light-years from Earth with a 9 light-year margin of error.
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.
58 Aquilae is a single star located around 520 light years from the Sun in the equatorial constellation of Aquila, near Eta Aquilae. 58 Aquilae is its Flamsteed designation. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.60. This object is moving closer to the Earth with a heliocentric radial velocity of −53 km/s, and may come as close as 161 light-years in around 1.8 million years.
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.
64 Aquilae, abbreviated 64 Aql, is a star in the equatorial constellation of Aquila. 64 Aquilae is its Flamsteed designation. It is a faint star that requires good viewing conditions to see, having an apparent visual magnitude of 5.97. The distance to 64 Aql, as determined from its annual parallax shift of 21.42 mas, is 152.2 light years. At that distance, the visual magnitude of the star is diminished by an extinction of 0.029 due to interstellar dust. It is moving closer to the Earth with a heliocentric radial velocity of −3.6 km/s.
68 Aquilae is a double star in the equatorial constellation of Aquila. 68 Aquilae is its Flamsteed designation. Its apparent magnitude is 6.12.
R Andromedae is a Mira-type variable star in the constellation Andromeda. Its spectral class is type S because it shows absorption bands of zirconium monoxide (ZrO) in its spectrum. It was among the stars found by Paul Merrill to show absorption lines of the unstable element technetium, establishing that nucleosynthesis must be occurring in stars. The SH molecule was found for the first time outside earth in the atmosphere of this star. The star is losing mass due to stellar winds at a rate of 1.09×10−6M☉/yr.
V Aquilae is a carbon star and semiregular variable star in the constellation Aquila. It has an apparent magnitude which varies between 6.6 and 8.4 and is located around 400 parsecs (1,300 ly) away.
T Cephei is a Mira variable star in the constellation Cepheus. Located approximately 600 light-years distant, it varies between magnitudes 5.2 and 11.3 over a period of around 388 days.
V1401 Aquilae is a single, semi-regular pulsating star in the equatorial constellation of Aquila. It has the designation HD 190390 from the Henry Draper Catalogue, and was formerly designated 64 Sagittarii. The evolutionary status of the star is unclear, and it has been classified as a post-AGB object, a UU Herculis variable, or belonging to the W Virginis variable subclass of the type II Cepheids. It is dimly visible to the naked eye with an apparent visual magnitude that fluctuates around 6.38. Based on parallax measurements, it is located at a distance of approximately 2,380 light years. It lies 21.5° from the galactic plane.
V1429 Aquilae is a candidate luminous blue variable multiple star system located in the constellation of Aquila. It is often referred to by its Mount Wilson Observatory catalog number as MWC 314. It is a hot luminous star with strong emission lines in its spectrum.
π1 Gruis (Pi1 Gruis) is a semiregular variable star in the constellation Grus around 530 light-years from Earth. It forms a close naked-eye double with π2 Gru four arc-minutes away.
S Cassiopeiae is a Mira variable and S-type star in the constellation Cassiopeia. It is an unusually cool star, rapidly losing mass and surrounded by dense gas and dust producing masers.
II Lupi is a Mira variable and carbon star located in the constellation Lupus. It is the brightest carbon star in the Southern Hemisphere at 12 μm.
HD 101584 is a suspected post-common envelope binary about 1,800 to 5,900 light-years distant in the constellation of Centaurus. The system is bright at optical wavelengths with an apparent visual magnitude of about 7. The primary is either a post-AGB star, but more likely a post-RGB star. The secondary is a red dwarf or possibly a low-luminosity white dwarf, which orbits the primary every 150-200 days. The system is surrounded by a slowly rotating circumbinary disk, probably with a face-on orientation towards the solar system and a size of about 150 astronomical units.