Star of the week: Fomalhaut

earthsky.org | 9/23/2017 | Larry Sessions
jenny124124 (Posted by) Level 3
Click For Photo: http://en.es-static.us/upl/2010/06/Fomalhaut_with_Disk_Ring_and_extrasolar_planet_b-300x200.jpeg

This image shows the debris ring around Fomalhaut and the location of its first known planet. This is the actual discovery image, published in the journal Science in November, 2008. Fomalhaut b was the first beyond our solar system visible to the eye in photographic images. Image via Hubble Space Telescope.

The star Fomalhaut is an autumn star for the Northern Hemisphere (spring star for the Southern Hemisphere). From our northerly latitudes, it’s sometimes called the Loneliest Star. It’s also famous in astronomical science as the first star with a visible exoplanet. Follow the links below to learn more about the star Fomalhaut.

Comparison - Fomalhaut - System - System - Wikimedia

A comparison of the Fomalhaut system with our own solar system via Wikimedia Commons.

Fomalhaut as a star, and a word about the Main Sequence. As determined by an analysis of its light, Fomalhaut is classified as an A3V star. It’s considerably hotter and heavier than our sun, as indicated by the “A3.” Imagine you could place our sun and Fomalhaut side by side in space – say, at 10 parsecs or 32.6 light-years away. In that case, Fomalhaut would outshine our sun in visible light by nearly 17 times. The “V” in Fomalhaut’s classification is called a luminosity class, and it designates the largest category of all, ordinary stars like our sun in the mature and stable part of their life spans.

Numbers - Letters - Astronomers - Main - Sequence

These numbers and letters refer to what astronomers call the Main Sequence, a way of categorizing stars by mass and luminosity. The Main Sequence follows the rather odd progression of OBAFGKM. Os are the hottest and most massive stars, and Ms are the coolest and least massive stars. In addition, there is a numerical subdivision running from 0 to 9 with each letter. Our sun is a G2V, as is Alpha Centauri. Since Fomalhaut’s designation is significantly to...
(Excerpt) Read more at: earthsky.org
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