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Regulus
Alpha (α) Leonis
Blue Star
Right Ascension | 10h 08m 22s | Best Seen | 3/1 - 7/1 |
Declination | 11° 58' 02" | Magnitude | 1.36 |
Constellation | Leo | ||
Actual |
Compared to Sun |
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Distance | 77 ly | -- |
Actual Brightness | -- | 127 |
Surface Temperature | ~19,000 ºF | ~1.9 |
Diameter (average) | ~2.6 million miles | ~3 |
Mass | -- | 4 |
Surface Gravity | -- | -- |
Surface Composition (by mass) | 74% hydrogen 24% helium 2% everything else |
same |
Spectral Type | B7 V | G2 V |
Density (gram/cubic cm) | -- | -- |
What To Look For Through The Telescope
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Recommended eyepiece: 24mm or 40 mm.
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When people look through the telescope a bright bluish point of light should be seen.
Regulus Information:
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Regulus is the 15th brightest star in the Northern Hemisphere’s night sky (22nd brightest in night sky when including Southern Hemisphere’s bright stars).
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Regulus is actually larger – and therefore puts off more light – than Sirius, the brightest star in the night sky. However, Sirius is brighter in the sky because it’s closer: Sirius is only 8.6 light years away.
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References
Item | Updated | Notes |
Coordinates | 2002-07-17 | SIMBAD |
Distance | 2002-07-17 | SIMBAD, with Hipparcos |
Actual Brightness | 2002-07-17 | with Scott’s The Flamsteed Collection |
Surface Temperature | 2002-07-17 | B7 temp close to 10,000K: assumed 11,000 K |
Diameter | 2002-07-17 | based on assumed 11,000K temp |
Mass | 2002-07-17 | mass-lum rel: L = M3.5 |
Surface Composition | 2003-01-06 | OK for all stars |
Spectral Type | – | |
Other Information | 2002-07-22 | 1. previous mass listing: 5 times our Sun – BUT could find no evidence 2. previous gravity: 15.5 times our Sun – BUT could find no evidence 3. previously: “2a. Has a companion star 440 billion miles away, or about 4,600 Earth-Sun distance (177"). 2b. Companion’s brightness: .5 Sun’s brightness (or 1/300 Regulus’ brightness)” – BUT could find no evidence 4. previous density: 0.04 – BUT how know this? 5. previous: 21st brightest star – BUT with Hipparcos, these 'ranks' ” |