Epsilon Aurigae

Here are the links I promised you all about the Epsilon Aurigae debris cloud imaged by the CHARA Array. This is the star I was discussing with the Docent at Mt. Wilson when he was explaining the CHARA Array. This is the star in that triangle I pointed out to some of you when we were looking at Capella through the 60″. I have nicknamed this one the “Weirdo Star:” because it has been a major mystery for more than 150 years.

1. Here is a video presentation explaining the system. This was put out by Timothy Ferris prior to the last two year long eclipse of the system.

2. Here is a video constructed using CHARA Array data of the beginning of the eclipse. Bear in mind that this video represents more than 6 months worth of data.

3. For those interested -here is a more detailed explanation. This star was extensively studied during the past eclipse using a worldwide collaboration between the Amateur, Professional, and Physics Communities


4. Here is the light curve of the eclipse. This chart contains visual estimates (black dots) and both V (green dots) and B (blue dots) measurements. When you hear the term “Color Index” or “B-V” index this is what they are referring to. The green measurements are standard “V” which approximates what the eye would see (green-yellow). The “B” or Blue filter measures the -wait for it- “Blueness”. The reference points are defined by certain well defined reference stars. For example the star Vega is defined to define the zero point where B-V=0. If the B-V is a positive number the star is redder and cooler than Vega. If the B-V is a negative number the star is bluer and hotter than Vega. As you can see from this light curve the B mag is dimmer than the V mag so B-V will be positive. For Epsilon Aurigae the value of B-V=.54 For the Sun the B-V = .66. So Epsilon Aurigae is a bit hotter and bluer than the Sun – yellowish white.

Of the dots in this graph 12 of the black ones are my measurements.

Dave Majors
CCAS (Central Coast Astronomical Society) centralcoastastronomy.org
AAVSO (American Association Of Variable Star Observers) aavso.org

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