Stars in our Universe January 2013

What are stars? Definition: a large sphere of plasma held together by gravity Compared to our closest star, the Sun: Some are very large, some are very small Some are very hot, some are “cold”

Constellations An observed pattern of stars in the sky They represent mythical characters, animals, or familiar objects Even though the stars look close together, they are really light years apart!

Polaris: The North Star Positioned almost directly over the North Pole All of the constellations in the Northern hemisphere revolve around it Think of Polaris as the point of Earth’s axis The movement of the other constellations around Polaris show that the Earth is rotating.

Absolute & Apparent Magnitudes Absolute Magnitude How bright the star is FOR REAL As in, if you were right next to it, this is how bright it would be Apparent Magnitude How bright the star looks like from Earth It may be bright to our eyes, but FOR REAL, it may not be as bright as the one further away…

Properties of Stars Color: indicates the temperature Red Color = cooler Blue/White Color = hotter Think back to the spectrum: Red waves are safer and so are cooler temperatures Blue waves are damaging and so are hotter temperatures

Spectroscope Acts like a prism and spreads the light out into colors Each dark line on the spectrum tells you what element is in the star Stars can have more than one element in them

Spectral Data - Lab Cut out your elements from your spectral data of given elements. These are the patterns for a specific element – like a fingerprint Do NOT cut out the stars from the second page Line up the spectral data with the star. If EVERY line matches up – your star has that element. On the star data, circle the elements that are in each star. Note: Even if 1 line does not match up – it does not have that element. It must fit perfectly.

Questions on worksheet 1.What elements are found in all 5 stars? 2.Why do you think these elements are found in all 5 stars? (Think about where they are on the Periodic Table) 3.Do any of the stars have all 8 elements? 4.What type of instrument do scientists use to collect star spectral data?