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Date: 27 Oct 2006 13:38:31
From: Robert Lunsford
Subject: Brightness of Betelgeuse
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I was out viewing the Orionid meteor shower this past weekend and was
surprised on how dim Betelgeuse was. It was just a shade fainter than
Aldebaran and its color was more intense than I ever recall. Did anyone else
notice this?
Bob Lunsford
San Diego, CA
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Date: 27 Oct 2006 16:26:51
From: Brian Tung
Subject: Re: Brightness of Betelgeuse
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Robert Lunsford wrote:
> I was out viewing the Orionid meteor shower this past weekend and was
> surprised on how dim Betelgeuse was. It was just a shade fainter than
> Aldebaran and its color was more intense than I ever recall. Did anyone else
> notice this?
Betelgeuse is an irregular variable. It pulses, sometimes becoming
larger but cooler and redder (and therefore dimmer overall) and
sometimes becoming smaller but hotter and less red (and therefore
brighter overall). At its smallest and brightest, it is just barely the
brightest star in Orion, but most of the time, it is somewhat dimmer
than Rigel. I seem to recall that its variation is on the order of a
magnitude or so.
However, I haven't looked at Betelgeuse recently. I'm hazarding a
guess--though an informed guess--as to the explanation.
--
Brian Tung <brian@isi.edu >
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.html
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Date: 28 Oct 2006 02:13:53
From: canopus56
Subject: Re: Brightness of Betelgeuse
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Robert Lunsford wrote:
> I was out viewing the Orionid meteor shower this past weekend and was
> surprised on how dim Betelgeuse was. . . .
Go to http://www.aavso.org/ and in the "Pick A Star" box type in "alpha
Ori". Display "recent values". Betelgeuse varies between 0.0 and 1.2
magnitudes. Recent values in the AAVSO at around 0.8 mags - near the
dim end of the scale.
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