Learning Goals: How do stars differ from moons and planets, and from one another? How does the classification of stars help us understand how they evolve over their lifetimes? What are the different types of stars? What happens when different types of stars die? Why is it important for us to understand stars? Bellwork and FYI + questions. = 9 Minutes (2 songs)

Bellwork and FYI. = 9 Minutes (2 songs)

Classifying Stars Questions of the day What characteristics help us organize stars into groups? Who determined those characteristics and how?

Who determined these characteristics? We are going to start with the Who determined these characteristics?

We are going to learn about the most important person in the field of star classification. Take notes on what you believe to be important. I wont tell you exactly what to write down. There will be multiple test questions about this person

-- Really Smart Scientist Classifying the stars has helped in all studies of the structure of the universe. No greater problem is presented to the human mind. -- Really Smart Scientist

Education/Awards graduated from Wellesley College (1884) became a student of astronomy at Radcliffe College (1894) received an M.A. from Wellesley College (1907) received an honorary doctorate from the University of Delaware (1918) was the first woman to receive a doctor of astronomy degree from Groningen University (1921) was the first woman to receive an honorary doctorate from Oxford (1925) received an honorary doctorate from Wellesley College (1925) received an honorary doctorate from Oglethorpe University (1935) received an honorary doctorate from Mount Holyoke College (1937)

Annie Jump Cannon (1863-1941)

Annie suffered a handicap in her youth and was very hard of hearing  born in Dover, Delaware on December 11, 1863 Annie suffered a handicap in her youth and was very hard of hearing At Wellesley College she pursued physics & astronomy After graduation, she became an expert in the new field of photography. Annie loved to travel and in 1892 she traveled through Europe taking pictures with her new box camera

Annie created a booklet of photos and prose from her trip Annie created a booklet of photos and prose from her trip. It was published and used as a souvenir for the Chicago World Fair in 1893. It was titled In the Footsteps of Columbus. While at home Annie became unhappy with the way her life was heading and wrote the following in her journal:

“I am sometimes very dissatisfied with my life here “I am sometimes very dissatisfied with my life here. I do want to accomplish something, so badly. There are so many things that I could do if I only had the money. And when I think that I might be teaching and making money, and still all the time improving myself it makes me feel unhappy and as if I were not doing all that I can.”

became a student of astronomy at Radcliffe. After her mother's death in 1894: Annie returned to Wellesley as an assistant in the physics department and became a student of astronomy at Radcliffe. took part in the first X-ray experiments in the country began her work at the Harvard College Observatory.

Annie observing in 1895 through a 4-inch reflecting telescope.

This picture was taken during the 1895-1896 academic year This picture was taken during the 1895-1896 academic year. This is the laboratory of then Wellesley professor and renowned physicist and astronomer Sarah Whiting.

Annie Cannon at Oxford in 1925 Annie Cannon at Oxford in 1925. She was the first woman to ever receive an honorary doctorate from this institution. It was awarded for her contributions to astrophysics.

In 1896 Annie was hired by Professor Edward Charles Pickering, director of the Harvard College Observatory, to catalogue variable stars and classify the spectra of southern stars.

Some of the women were referred to as “computers” because they handled star classification and complex data reduction. They were paid 50 cents an hour. Other women who worked there as assistants were referred to as “recorders” because they recorded the data..

Stellar classification according to line patterns began Stellar classification according to line patterns began. This was not easy to do. Annie excelled because of her sharp eye and memory. The following image is one photographic plate containing stellar spectra. For this particular field she averaged 3 stars a minute. She ended up categorizing over 350,000 stars in her career

What characteristics help us organize stars? Now we are going to figure out What characteristics help us organize stars?

Classifying Stars What properties could we use to classify stars? Why? Temperature Color Size Spectrum

Classification of Stars -historical Originally- # classification… 1= bright, 6=dim Remember Hipparchus? Then….

Then- spectrum analysis… strength of Hydrogen, starts at A, goes through the alphabet

Classification - current Use: Spectrum, Temperature, and Size *It was easier to just rearrange the letters than to reclassify everything… Get rid of repeated properties Put in temperature order Temperature and Mass relationship Temperature and stellar life cycle relationship

A A B B C D E F F G G H I J K K L M M N O O

Stars are classified by: Spectral Class (color , temperature, spectral lines) - O,B,A,F,G,K,M -O:Blue, B:Blue/white, A:white, F:yellow/white, G:yellow, K:orange, M:red Temperature (range within class) -0, 1,2,3,4,5,6,7,8,9 -0=hottest, 9=coolest Magnitude (brightness and size) -0, I, II, III, IV, V, VI, VII -0 –hypergiants, I –supergiants (Ia and Ib), II-bright giants, III –normal giants, IV- subgiants, V- main sequence (dwarf), VI- subdwarf, VII-white dwarf

What characteristics do these stars have? B8 I – Rigel K5III – Aldebaran M2I – Betelgeuse F5 IV - Procyon A1V – Sirius G2V- Sun O9.5II -- Mintaka

Classifying Stars What characteristics help us organize stars into groups? Who determined those characteristics and how?