Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Aquarius |
Right ascension | 23h 43m 49.46343s [1] |
Declination | −15° 17′ 04.1763″ [1] |
Apparent magnitude (V) | 5.2 - 12.4 [2] |
Characteristics | |
Spectral type | M5e-M8.5e + pec [2] |
U−B color index | −0.62 [3] |
B−V color index | +1.98 [3] |
Variable type | Mira + Z And [2] |
Astrometry | |
Radial velocity (Rv) | −22.0 [4] km/s |
Proper motion (μ) | RA: +40.587 [1] mas/yr Dec.: −30.411 [1] mas/yr |
Parallax (π) | 2.5931 ± 0.3333 mas [1] |
Distance | approx. 1,300 ly (approx. 390 pc) |
Orbit [5] | |
Period (P) | 15,943±471 |
Semi-major axis (a) | 0.071 - 0.084" (14.2 - 16.8 AU) |
Eccentricity (e) | 0.25±0.07 |
Inclination (i) | 70° |
Details | |
A | |
Mass | 1 - 1.5 [5] M☉ |
Radius | 430 [5] R☉ |
Luminosity | 4,780 [6] L☉ |
Surface gravity (log g) | −0.5 [6] cgs |
Temperature | 2,800 [6] K |
B | |
Mass | 0.6 - 1 [5] M☉ |
Radius | >0.1 [7] R☉ |
Luminosity | 5-20 [8] L☉ |
Temperature | 60,000 [8] K |
Other designations | |
Database references | |
SIMBAD | data |
Data sources: | |
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) |
R Aquarii (R Aqr) is a variable star in the constellation Aquarius. [9]
R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary system. The orbital period is approximately 44 years. [5] The main Mira-type star is a red giant, and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered by Karl Ludwig Harding in 1810. It has a distance of about 390 parsecs, [1] and is one of the nearest symbiotic stars and a well-known jet source. [10] The two components have been resolved at a separation of 55 mas. [11]
By its gravitational pull, the white dwarf draws in material from the red giant and occasionally ejects some of the surplus in loops to form the nebula seen in the linked image. [12] The whole system appears reddened because it is situated in a very dusty region of space, and its blue light is absorbed before reaching Earth.
The nebula around R Aquarii is also known as Cederblad 211. [13] It is possible that the nebula is the remnant of a nova-like outburst, which may have been observed by Japanese astronomers, in the year 930 AD. [14] It is reasonably bright but small and dominated by its central star. Visual observations are difficult and rare. [15] The central region of the jet shows an ejection that took place around 190 years ago, as well as much younger structures. [16]
The giant primary star is a Mira variable, a star that pulsates and changes temperature, leading to very large visual brightness changes. The total range of 5.2 - 12.4 is a variation of 750 times in brightness, from a naked eye star to one beyond the range of binoculars. The pulsations occur every 390 days but are not entirely regular. [2]
Lambda Aquarii, informally known as Hydor, is a variable star in the equatorial constellation of Aquarius. The name is Latinized from the Bayer designation λ Aquarii. The apparent visual magnitude of this star ranges from 3.57 down to 3.80, which is bright enough to be visible with the naked eye. It lies just 0.39 degrees south of the ecliptic and so is subject to lunar occultations. The star is eclipsed by the sun from about 1-4 March; thus the star can be viewed the whole night, crossing the sky, in early September, in the current epoch. Lambda Aquarii is located at a distance of approximately 310 light-years (95 pc) from the Sun based on parallax, but is drifting closer with a radial velocity of −10.5 km/s.
Mu Aquarii, Latinized from μ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with a combined apparent visual magnitude of 4.7. Based upon parallax measurements, the distance to this system is about 157 light-years. It is drifting closer to the Sun with a radial velocity of −9.1 km/s.
Chi Aquarii, Latinized from χ Aquarii, is the Bayer designation of a star in the equatorial constellation of Aquarius. The distance to this star, based upon parallax measurements with a 7% margin of error, is roughly 610 light-years. It is visible to the naked eye with an apparent visual magnitude of about 5.
Rho Aquarii, Latinized from ρ Aquarii, is the Bayer designation for a binary star system in the equatorial constellation of Aquarius. It is visible to the naked eye with an apparent visual magnitude of +5.34. Based upon parallax measurements, this star is at a distance of roughly 870 light-years from Earth. It is drifting closer with a radial velocity of –9 km/s. The proximity of this star to the ecliptic means it is subject to lunar occultations.
3 Aquarii is a variable star in the equatorial constellation of Aquarius. 3 Aquarii is the Flamsteed designation; it also bears the Bayer designation k Aquarii and the variable star designation EN Aquarii. With a mean apparent visual magnitude of 4.429, it is visible to the naked eye in dark skies. It has an annual parallax shift of 5.57 milliarcseconds with a 5% margin of error, which translates to a physical distance of around 590 light-years from Earth.
104 Aquarii (abbreviated 104 Aqr) is a star in the equatorial constellation of Aquarius. 104 Aquarii is the Flamsteed designation, although it also bears the Bayer designation A2 Aquarii. Based on an annual parallax shift of only 3.89 ± 0.25 milliarcseconds, the distance to this star is about 840 light-years (260 parsecs). At that range, the brightness of the star in the V-band is reduced by 0.10 magnitudes as a result of extinction caused by intervening gas and dust.
94 Aquarii is a triple star system in the equatorial constellation of Aquarius. 94 Aquarii is the Flamsteed designation. The brightest member has an apparent visual magnitude of 5.19, making it visible to the naked eye. The parallax measured by the Gaia spacecraft yields a distance estimate of around 73 light-years from Earth.
74 Aquarii is a triple star system in the constellation of Aquarius. 74 Aquarii is its Flamsteed designation and it also bears the variable star designation HI Aquarii. The combined apparent visual magnitude is 5.8, although it is very slightly variable, and it is located at a distance of 590 light-years from Earth.
82 Aquarii is a star in the equatorial constellation of Aquarius. 82 Aquarii is its Flamsteed designation. It has an apparent visual magnitude of 6.15, which, according to the Bortle Dark-Sky Scale, means it is a faint star that requires dark rural skies to view. The annual parallax shift of 82 Aquarii is 3.6764±0.1715 mas, which equates to a distance of roughly 890 light-years from Earth. Because this star is positioned near the ecliptic, it is subject to lunar eclipses.
29 Aquarii is a binary star system located around 590 light years away from the Sun in the equatorial constellation of Aquarius. 29 Aquarii is the Flamsteed designation; the system also bears the variable star designation DX Aquarii. It is a challenge to view with the naked eye, appearing as a dim star with a combined apparent visual magnitude of 6.39. The system is moving further from the Earth with a heliocentric radial velocity of about +15 km/s.
Z Andromedae is a binary star system consisting of a red giant and a white dwarf. It is the prototype of a type of cataclysmic variable star known as symbiotic variable stars or simply Z Andromedae variables. The brightness of those stars vary over time, showing a quiescent, more stable phase and then an active one with a more pronounced variability and stronger brightening and/or dimming.
U Aquarii, abbreviated U Aqr, is a variable star in the equatorial constellation of Aquarius. It is invisible to the naked eye, having an apparent visual magnitude that ranges from 10.6 down to as low as 15.9. Based on parallax measurements, the distance to this star is approximately 38 kly (12 kpc). In 1990, W. A. Lawson and associates provided a distance estimate of 43 kly (13.2 kpc) based on the assumption of a bolometric magnitude of −5. It appears to lie several kiloparsecs below the galactic plane, and thus may belong to an old stellar population.
R Reticuli, also listed under the duplicate variable star designation S Reticuli, is a Mira variable star in the southern constellation Reticulum. It is an aging red giant star on the asymptotic giant branch with a stellar classification that varies between M4e to M7.5e, being hottest near maximum visual magnitude. The brightness of the star varies between apparent visual magnitudes 6.35 and 14.2 with an average period of 281.08±0.58 d. The mean maximum magnitude is 7.57 and the mean minimum magnitude 13.80.
LP Aquarii is a pulsating variable star in the constellation of Aquarius that varies between magnitudes 6.30 and 6.64. The position of the star near the ecliptic means it is subject to lunar occultations.
14 Aquarii is red giant star. 14 Aquarii is the Flamsteed designation; it also bears the variable star designation IW Aquarii. It is a semiregular variable with an amplitude of a tenth of a magnitude, and shows variations on a timescale of just one day.
QZ Puppis is a class B2.5V star in the constellation Puppis. Its apparent magnitude is 4.5 and it is approximately 650 light years away based on parallax.
HD 65750, also known as V341 Carinae is a bright red giant star in the constellation Carina. It is surrounded by a prominent reflection nebula, known as IC 2220, nicknamed the Toby Jug Nebula.
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.
T Leporis is a variable star in the constellation of Lepus, the Hare. It is located half a degree from ε Leporis in the sky; its distance is approximately 1,100 light years from the Solar System. It has the spectral type M6ev, and is a Mira variable — as is R Leporis, in the same constellation — whose apparent magnitude varies between +7.40 and +14.30 with a period of 368.13 days.
HM Sagittae is a dusty-type symbiotic nova in the northern constellation of Sagitta. It was discovered by O. D. Dokuchaeva and colleagues in 1975 when it increased in brightness by six magnitudes. The object displays an emission line spectrum similar to a planetary nebula and was detected in the radio band in 1977. Unlike a classical nova, the optical brightness of this system did not rapidly decrease with time, although it showed some variation. It displays activity in every band of the electromagnetic spectrum from X-ray to radio.