# Science of the Stars

Topics: Star, Stellar classification, Main sequence Pages: 4 (1259 words) Published: June 28, 2013
Science of Stars
Nancy Vasquez
SCI 151
September 23, 2012
Robert Austin

Abstract

When discussing the Solar System, the planets are what are mostly thought of. Many other objects orbit around the sky such as stars, asteroids and meteors. Stars have many properties of which will be discussed throughout this paper.

Properties of Stars
* Stars are determined by their brightness, distance, luminosity, radius, chemical composition and temperature (Strobel, 2007). * When determining the distance to a star, we use two methods; the parallax and the parsec. The parallax is the angular shift which is one of the angles in a triangle. It is also the distance between to other points on the other side of the triangle. This angle is used to calculate the all sides of the triangle. The parallax method is also known as the surveyor’s method. * The parsec method is used in astronomy as a unit of length; the parallax of one arc second or” par sec.” In simpler terms it is the measurement of an angle. This method is used is the most ancient and standard method in determining stellar distances (Parsec, 2009). * To put the two together a parsec is the parallax of one arc second. To make the understanding easier, we measure the distance from the star to the Sun. At the sun point, draw an equal circle around the star. You do the same thing with the sun and the earth. Draw a straight line from the Earth through the Sun. The distance from a star point to the Sun formula is below (Bennett, 2010). * Distance (d) = radius of Earth’s orbit (a=1AU) / parallax angle. *

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* Period-luminosity relation
* Period –Luminosity was first discovered by Henrietta Leavitt of Peru, in 1908 when studying the Small Magellanic Cloud. She was using a photographic refractor to catalog 1777 variable stars from the photographic plates taken between 1893 and 1906. She had found that of the 1777 stars, 16 had period ranges from...

Bennett, D. S. (2010). The Cosmic Perspective: Stars, Galaxies & Cosmology (Vol. 8). Boston, MA: Addison-Wesley. Retrieved September 23, 2012
Strobel, N. (2007, June 2). Stars--What re they like? Retrieved from Astronomy Notes: http://www.astronomynotes.com/starprop/s2.htm