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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
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

  1. Recommended eyepiece: 24mm or 40 mm.

  2. When people look through the telescope a bright bluish point of light should be seen.

Regulus Information:

  1. 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).

  2. 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' ”