Alioth

Alioth

I chose Alioth because it is brightest stars in the constellation Ursa Major.
Chemicals: Potassium

Location: right ascension 12h 54m 01.74959s, declination +55° 57′ 35.3627″
Stellar Classification: A1p

Epsilon Ursae Majoris, or Alioth, (Epsilon UMa, ε Ursae Majoris, ε UMa) is the brightest star in the constellation Ursa Major, right ascension 12h 54m 01.74959s, declination +55° 57′ 35.3627″, and at magnitude 1.76 is the thirty-first brightest star in the sky. It has the traditional name Alioth. It is the star in the tail of the bear closest to its body, and thus the star in the handle of the Big Dipper (Plough) closest to the bowl.

According to Hipparcos, Alioth is 81 light years (25 parsecs) from Earth. Its spectral type is A1p; the "p" stands for peculiar, as the spectrum of its light is characteristic of an Alpha2 Canum Venaticorum variable. Alioth, as a representative of this type, may harbor two interacting processes. First, the star's strong magnetic field separating different elements in the star's hydrogen 'fuel'. In addition, a rotation axis at an angle to the magnetic axis may be spinning different bands of magnetically sorted elements into the line of sight between Alioth and the Earth. The intervening elements react differently at different frequencies of light as they whip in and out of view, causing Alioth to have very strange spectral lines that fluctuate over a period of 5.1 days. The kB9 suffix to the spectral type indicates that the calcium K line is present and representative of a B9 spectral type even though the rest of the spectrum indicates A1.

With Alioth, the rotational and magnetic axes are at almost 90 degrees to one another. Darker (denser) regions of chromium form a band at right angles to the equator. Alioth has a relatively weak magnetic field, 15 times weaker than α CVn, but it is still 100 times stronger than that of the Earth.

Sources:
Wikipedia, the free encyclopedia. (2015, September 22). Epsilon Ursae Majoris. Retrieved September 27, 2015, from https://en.wikipedia.org/wiki/Epsilon_Ursae_Majoris

 Visible Spectra of the Elements. (n.d.). Retrieved September 28, 2015, from http://www.umop.net/spctelem.htm