Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Hydra |
Right ascension | 13h 49m 01.998s |
Declination | −28° 22′ 03.49″ |
Apparent magnitude (V) | 7.7 - 11.6 [2] |
Characteristics | |
Spectral type | M7.5e-M9ep [3] |
Apparent magnitude (J) | -1.7 [4] |
Variable type | Mira |
Astrometry | |
Parallax (π) | 10.18 ± 2.36 mas [5] |
Distance | 98 [6] pc |
Details | |
Radius | 229 [7] –560 [8] R☉ |
Luminosity | 7,330 [6] L☉ |
Temperature | 2,500 [9] - 3,129 [7] K |
Other designations | |
Database references | |
SIMBAD | data |
W Hydrae is a Mira-type variable star in the constellation Hydra. The star is nearly located within the Solar neighborhood, between 75 and 120 parsecs, likely at 320 light years from the Sun. It has a visual apparent magnitude range of 5.6 to 10. In the near-infrared J band it has a magnitude of -1.7, [4] is the 7th brightest star in the night sky, and is even brighter than Sirius.
The star also shows signs of intense water emissions, indicative of the presence of a wide disk of dust and water vapour. [9] Such emissions cover a zone spanning between 10.7 Astronomical Units (within Saturn's orbital zone) and 1.2 parsecs (or nearly 247,500 Astronomical Units, as far away as the Oort Cloud in Solar System).
A Gamma Cassiopeiae variable is a type of variable star, named for its prototype γ Cassiopeiae.
R Hydrae, abbreviated R Hya, is a single star in the equatorial constellation of Hydra, about 2.7° to the east of Gamma Hydrae. It is a Mira-type variable that ranges in apparent visual magnitude from 3.5 down to 10.9 over a period of 389 days. At maximum brightness the star can be seen with the naked eye, while at minimum a telescope of at least 5 cm is needed. This star is located at a distance of approximately 480 light-years from the Sun but is drifting closer with a radial velocity of −10 km/s.
S Orionis is an asymptotic giant branch star in the constellation Orion, approximately 480 parsecs (1,600 ly) away. It varies regularly in brightness between extremes of magnitude 7.2 and 14 every 14 months.
R Aquarii is a variable star in the constellation Aquarius.
W Andromedae is a variable star in the constellation of Andromeda. It is classified as a Mira variable and S-type star, and varies from an apparent visual magnitude of 14.6 at minimum brightness to a magnitude of 6.7 at maximum brightness, with a period of approximately 397.3 days. The star is losing mass due to stellar winds at a rate of 2.79×10−7M☉/yr.
TX Camelopardalis is a Mira-type variable star in the constellation Camelopardalis. It is a classical long period variable star with pulsational period of 558.7 days. Water masers have been observed around the star.
V Hydrae is a carbon star in the constellation Hydra. To date perhaps uniquely in our galaxy it has plasma ejections/eruptions on a grand scale that could be caused by its near, unseen companion.
U Camelopardalis is a semiregular variable star in the constellation Camelopardalis. Based on parallax measurements made by the Hipparcos spacecraft, it is located about 3,000 light-years away from the Earth. Its apparent visual magnitude is about 8, which is dim enough that it cannot be seen with the unaided eye.
21 Leonis Minoris is a star in the constellation of Leo Minor. With an apparent magnitude of about 4.5, the star is faintly visible to the naked eye. Parallax estimates made by the Hipparcos spacecraft put it at a fairly close distance of about 92.1 light-years away from the Earth. It is considered a member of the Sirius supercluster.
13 Monocerotis is a class A0 Ib star in the constellation Monoceros. Its apparent magnitude is 4.5 and it is approximately 780 parsecs (2,500 ly) away.
W Canis Majoris is a carbon star in the constellation Canis Major. A cool star, it has a surface temperature of around 2,900 K and a radius 251 times that of the Sun, with a bolometric absolute magnitude of −4.13 and distance estimated at 443 or 445 parsecs based on bolometric magnitude or radius. The Gaia Data Release 2 parallax of 1.8049±0.1454 milliarcseconds implies a distance of about 555 parsecs.
AH Scorpii is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known by radius and is also one of the most luminous red supergiant stars in the Milky Way.
R Geminorum is a Mira variable and technetium star in the constellation Gemini. It is located approximately 850 parsecs (2,800 ly) away.
W Cygni is a semi-regular variable star in the constellation Cygnus, located 570 light-years from Earth. It lies less than half a degree southeast of ρ Cygni. W Cygni is, at times, a naked-eye star but it was not given a Bayer or Flamsteed designation. It has been proposed as a binary star system with a hotter main sequence companion, but this has not been confirmed.
R Leonis Minoris is a Mira variable type star in the constellation Leo Minor. It ranges between apparent magnitude 6.3 and 13.2, and spectral types M6.5e to M9.0e (Tc:), over a period of 372 days.
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.
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.
IK Tauri or NML Tauri is a Mira variable star located about 280 parsecs (910 ly) from the Sun in the zodiac constellation of Taurus.
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.
R Fornacis is a Mira variable and carbon star located in the constellation Fornax. It is around 1,800 light years away based on parallax measurements.