About Adhafera
Description
Adhafera, Zeta Leonis, is an F-type giant of spectral class F0 IIIa about 274 light-years away. It marks the top of the Sickle of Leo — the distinctive backward-question-mark asterism formed by the Lion's head and mane. Adhafera shines at magnitude 3.44, has a mass of about 3 Suns, and is slightly variable due to mild surface pulsations. A faint optical companion is visible at 5.6 arcminutes — far too distant to be physically associated.
Observing Tips
Adhafera forms the topmost point of the Sickle, with Algieba just below it. Binoculars reveal the distant optical companion (magnitude 6) as a wide, unrelated pair. Adhafera is a relatively modest white-yellow point compared to the brighter Regulus anchoring the base of the Sickle. Best observed February through May.
History
The name comes from the Arabic "al-ḍafīrah" meaning "the braid" or "tuft of hair" — a reference to the lion's mane. The IAU formally adopted the name in 2016.
Fun Facts
Adhafera sits at a galactic latitude of 51 degrees, far above the Milky Way plane. Combined with its relatively young age (about 600 million years), this makes it a useful calibration star for surveys of intermediate-age disk stars in this rarely sampled region of the sky.
Observe
1Physical Properties
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
8
Compare Stars
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Spectral Classification
10
Hertzsprung-Russell Diagram
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Stellar Lifecycle
12
Blackbody Spectrum
13
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
14
Stellar Fusion
Discover
15Stellar Notes
16
Light Travel Time Machine
17
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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