BETELGEUSE (ALPHA (α) ORIONIS)
RED SUPERGIANT STAR

Right Ascension:
5h 53m 48s

Best Seen:
1/1 - 4/15

Declination:
7º 24' 14"

Magnitude:
0.45

Computer File:
betelgeu

Constellation:
Orion

Actual

Compared to Sun

Distance

427 l.y.

--

Actual Brightness

--

8,900

Surface Temperature

5,600 ºF

0.56

Diameter

~ 800 million miles

~ 930

Mass

--

20

Surface Gravity

--

--

Surface Composition (by mass)

74% hydrogen 24% helium 2% everything else

same

Spectral Type

M2 Ib

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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 reddish-orange point of light should be seen.

BETELGEUSE INFORMATION:

  1. Betelgeuse is the 7th brightest star in the Northern Hemisphere’s night sky (9th brightest if including the Southern Hemisphere’s bright stars).

  2. An irregularly pulsating red supergiant – its diameter may vary as much as 60% during the whole cycle.

  3. Note the size of this star: if Betelgeuse were placed in our solar system at our sun’s position, Mercury, Venus, Earth, Mars, and maybe even Jupiter would be inside Betelgeuse!

  4. This is the biggest star seen from Earth, and probably one of the biggest anywhere.

Item
Updated Notes

Coordinates 01-06-2003
tweaked a bit

Magnitude
01-06-2003
previously 0.70 – BUT SIMBAD says 0.58, and Flamsteed says 0.45

Distance
01-06-2003
previously 520 – BUT now OK with Scott’s The Flamsteed Collection and SIMBAD

Actual Brightness
01-06-2003
previously 14,000 – BUT now OK with Flamsteed

Surface Temperature 01-06-2003
can’t find direct support, but OK with numbers given in Flamsteed

Diameter
01-06-2003
previously:480-800 million miles / 550-920 times sun – BUT think it’s safe to say over 800 million - beyond Jupiter’s orbit - like said in http://antwrp.gsfc.nasa.gov/apod/ap970216.html

Mass
01-06-2003
can find no support, but sounds good

Surface Gravity

Surface Composition 01-06-2003
OK for all stars

Spectral Type
01-06-2003
OK with Scott’s Flamsteed

Density 01-06-2003
previously: <10-6 – BUT can find no support for this

Other Information
01-06-2003
OK