Zeta Hydrae — Star in Hydra
About Zeta Hya
Description
Zeta Hydrae is a yellow giant of spectral type G9II-III at magnitude 3.11 in Hydra. Located about 167 light-years from Earth, it has a luminosity of roughly 132 times solar and a surface temperature of about 4,900 K. It lies in the body of the Water Snake, the longest constellation in the sky.
Observing Tips
Zeta Hya lies in the long, winding body of Hydra, southeast of the distinctive head asterism. The head of Hydra (a small group of stars south of Cancer) is easy to find, and Zeta lies along the body stretching eastward. Best observed from February through May. Hydra's body extends so far that it takes several months for the whole constellation to clear the horizon.
History
Zeta Hydrae has no traditional proper name. Hydra is the largest of the 88 modern constellations, stretching nearly 100 degrees across the sky. It represents the Lernaean Hydra, the multi-headed water serpent slain by Hercules as one of his twelve labors.
Fun Facts
Hydra is so long that when its head is rising in the east, its tail is still below the western horizon. The constellation takes over six hours to fully cross the meridian. Zeta Hya sits roughly at the constellation's midpoint.
Observe
1Physical Properties
2Position & Identifiers
3How easy to spot?
| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | Easy | Easy | Medium+ |
| 50 mm finder 50mm finder | Easy | Easy | Easy |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
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5Survey Image
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Explore
7
Size Comparison
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Compare Stars
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Spectral Classification
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Hertzsprung-Russell Diagram
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Stellar Lifecycle
12
Blackbody Spectrum
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Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15
Light Travel Time Machine
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Relativistic Travel
Nearby in the Sky
Other targets within a few degrees — pan your scope a little and keep exploring.
Visibility scores assume a 150 mm Newton at Bortle 4.
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