Aquarius has a few nice binaries, a unique variable, and a few deep sky objects of some interest (but the Messiers here are generally sub-par). The stars are generally fourth magnitude.
The most notable asterism is of the water jug itself, tipped and pouring water. This small asterism, which fits nicely into a binocular field of view, is just west of alpha Aquarii and made up of zeta Aqr and three other stars.
Double stars in Aquarius:
Zeta2 Aquarii and zeta1 Aquarii form a binary of two equal white stars with an orbit of 760 years.
Zeta2 Aquarii is the primary: 4.4, 4.6; current PA 266º and separation: 2.3".
Struve 2944 is a nice triple system, with all three in a neat line.
AB: 7.0, 7.5; PA 276º, separation 2.5".C: 8.4; PA 106º, separation 50".
The binary is 2º due east of kappa Aquarii.
Struve 2988 is a very attractive pair of equal stars: 7.2, 7.2; PA 101º, separation 3.5".
The binary is 3º SW of psi1 Aquarii.
Variable stars in Aquarius:
The most remarkable variable in the constellation is R Aquarii, usually listed as a "Mira variable". Yet this red giant isn't your normal long-period variable; it is a 'symbiotic star', resembling Z Andromedae.
"Z Andromedae" stars are those which show two separate spectra, indicating two quite different temperatures, one cool, the other very hot. This phenomenon is caused by a very close binary system, which the larger star the cooler one, the small star(perhaps a white dwarf) the hot one.
And in fact, R Aquarii has a small blue companion, which is encircled by a gas cloud. When this small star eclipses the giant, the visual magnitude of the primary drops several degrees.
The star has a period of 386.96 days and a range from 5.8 to 12.4; the best time to view this star after the year 2000 is in 2005, in the first week of September.
The most notable asterism is of the water jug itself, tipped and pouring water. This small asterism, which fits nicely into a binocular field of view, is just west of alpha Aquarii and made up of zeta Aqr and three other stars.
Double stars in Aquarius:
Zeta2 Aquarii and zeta1 Aquarii form a binary of two equal white stars with an orbit of 760 years.
Zeta2 Aquarii is the primary: 4.4, 4.6; current PA 266º and separation: 2.3".
Struve 2944 is a nice triple system, with all three in a neat line.
AB: 7.0, 7.5; PA 276º, separation 2.5".C: 8.4; PA 106º, separation 50".
The binary is 2º due east of kappa Aquarii.
Struve 2988 is a very attractive pair of equal stars: 7.2, 7.2; PA 101º, separation 3.5".
The binary is 3º SW of psi1 Aquarii.
Variable stars in Aquarius:
The most remarkable variable in the constellation is R Aquarii, usually listed as a "Mira variable". Yet this red giant isn't your normal long-period variable; it is a 'symbiotic star', resembling Z Andromedae.
"Z Andromedae" stars are those which show two separate spectra, indicating two quite different temperatures, one cool, the other very hot. This phenomenon is caused by a very close binary system, which the larger star the cooler one, the small star(perhaps a white dwarf) the hot one.
And in fact, R Aquarii has a small blue companion, which is encircled by a gas cloud. When this small star eclipses the giant, the visual magnitude of the primary drops several degrees.
The star has a period of 386.96 days and a range from 5.8 to 12.4; the best time to view this star after the year 2000 is in 2005, in the first week of September.
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