Twinkle Twinkle Little Star

Some facts about stars include: size, mass, color, and temperature.

A star’s size is not the same as its mass.  Size refers to how big a star is, how much room it takes up in space. Mass, the intrinsic property of the star, is not equivalent to its weight. Weight refers to the gravitational force exerted upon an object . http://hyperphysics.phy-astr.gsu.edu/hbase/mass.html

 Color is a result of temperature. Like the flame in a fireplace, the tip of the flame is not as hot as the base of the flame. The tip is a cool red while the base of the flame near the fuel source is white hot. Not only does the color of a star tell us about how hot it is, but it also tells about what the star is made of. Colors form a spectrum. Astronomers aim a spectrograph at stars to get their color spectrum. The spectrum’s specific signature lines tell what fires the individual star.  Looking at the night sky, we can see that stars come in all colors. The sun, as we can see, is yellow. Betelgeuse, on the other hand is a red star, and Rigel is blue. Albeiro is purple, while its companion is orange.
http://www.webexhibits.org/causesofcolor/18B.html

Yes, Albeiro has a companion, because stars like to get together. They group by two’s, three’s and even four’s. Multiple stars hanging together are called star clusters.

Binary stars are two stars that revolve around each other. These systems are very common in our universe. Cor Caroli, Alcor and Mizar are binary stars. Such binary systems are important because from them we can only discover the true mass of a star. http://en.wikipedia.org/wiki/Binary_star

Some stars pulsate. These are called variable stars because they will be brighter or dimmer on any given night. There are several types of variable stars. Long period variables are usually older red giants whose pulse can last hundreds of days to years. Short period variables like Cepheids and RR Lyra stars are bright and pulse regularly in one to fifty days. Both types are useful to the field of astronomy.
 http://www.daviddarling.info/encyclopedia/V/variablestar.html
 Much of the pioneering work on stars was initiated by the Harvard girls. Annie Cannon worked out stellar classifications, while Henrietta Leavitt formulated the period luminosities of variable stars. Others included Williamena Fleming and Antonia Maury  

http://www.womanastronomer.com/harvard_computers.htm

http://www.sdsc.edu/ScienceWomen/cannon.html

http://www.pbs.org/wgbh/aso/databank/entries/baleav.html

Links can enlighten much about our twinkling stars. More on clusters next week.