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 | 320+98 −59 ly (98+30 −18 pc) [5] |
Details | |
Mass | 2.14+1.07 −0.71 [6] M☉ |
Radius | 436+134 −80 [7] [a] R☉ |
Luminosity | 9,290+2,460 −1,940 [6] L☉ |
Temperature | 3,000 [6] 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, at 320 light years from the Solar System. 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. [8] 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).
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.
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.
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.
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.
Iota Herculis is a fourth-magnitude variable star system in the constellation Hercules, consisting of at least four stars all about 139 parsecs away. The brightest is a β Cephei variable, a pulsating star.
S Pegasi is a Mira variable star in the constellation Pegasus. It varies between magnitude 7 and 13 with a period of 319.22 days. It is believed to be pulsating in the first overtone. First overtone pulsators have masses less than 1.8 M☉ at a temperature of 2,107 K, and less than 1.4 M☉ at the luminosity of S Pegasi.
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 234 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. It is a variable star, whose brightness ranges from magnitude 6.35 to 7.90. At its brightest, it might be very faintly visible to the naked eye of an observer with ideal observing conditions.
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 Coronae Borealis is a Mira-type long period variable star in the constellation Corona Borealis. Its apparent magnitude varies between 7.8 and 14.3 over a period of 238 days.
U Microscopii is a Mira variable star in the constellation Microscopium. It ranges from magnitude 7 to 14.4 over a period of 334 days. The Astronomical Society of Southern Africa in 2003 reported that observations of U Microscopii were very urgently needed as data on its light curve was incomplete.
AC Herculis, is an RV Tauri variable and spectroscopic binary star in the constellation of Hercules. It varies in brightness between apparent magnitudes 6.85 and 9.0.
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.
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.
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.