Star Life Cycles and Nuclear Science 2013 V2 31 Slides, I hope you like it.

(1 & 2) Kilometers One kilometer = 1000 meters Kilometers are used to measure distances on Earth. www.bnsc.gov.uk/.../ae/earth_splash.jpg

(3 & 4) Astronomical Units One Au is the average distance between the Earth and the Sun. The solar system is measured in Aus. www.floridastars.org/icons/solsysna.gif

The Milky Way is measured in light years. A light year is the distance light travels in one year. The Milky Way is 100,000 Light Years across The Milky Way is measured in light years. http://apod.nasa.gov/apod/ap960213.html

(7&8) Parsecs Parsec is short for parallax second. Distances Between galaxies are measured in parsecs. http://www.smv.org/hastings/student2.htm

Blue = young stars, yellow = middle aged stars, red = old stars. (10) Star Life Cycles This theory explains why the stars we see have vastly different appearances. Blue = young stars, yellow = middle aged stars, red = old stars.

(11,12 &13) Hertzprung – Russel (HR) diagram The HR diagram plots star absolute brightness on the y-axis and star surface temperature on the x-axis

(14 - 19) The Main Sequence Most stars including the Sun are in their mid-life. Most stars including the Sun are plotted in the main sequence of the HR diagram. Super-Giants Main Sequence Stars Giants The Sun White Dwarfs

(20 & 21) Apparent Brightness The apparent brightness is what a star looks like from Earth http://hou.lbl.gov/~vhoette/Explorations/PleiadesStars/index.html It depends on a star’s: Temperature, size, distance from Earth

(22 - 24) Mass and Life Cycle The life cycle a star will follow depends on its mass. . Super-giant stars such as Polaris end their lives in supernova explosions. Small to medium stars like the Sun end their lives as white dwarfs.

(25 – 32) Life Cycle of the Sun The sun is: a medium sized star 92% H and 8% He yellow and middle aged 5 billion years old The Sun Red Giant With Oxygen & Carbon Core When the H runs out, the sun swells up to become a Red Giant as large as the orbit of Mars. Yikes! White Dwarf The sun will die in 5 billion years. the sun will end its life as a white dwarf, a dead star.

31. (again) A star is born when gravity crushes the nebula until fusion starts in its core.

The life cycle of a star depends on its mass At the end of the life of a super giant star, it explodes in the largest bang the universe has to offer. http://imagine.gsfc.nasa.gov/docs/science/know_l1/supernovae.html

33. Hertzprung – Russel (HR) Diagram The HR diagram plots star absolute brightness on the y-axis and star surface temperature on the x-axis

(34 & 35) Fusion H + H  He + energy Fusion powers the stars

Solar energy travels to the Earth in waves. 36. Radiation From the Sun All stars radiate: Heat, (IR), Visible light (VIS) and Ultraviolet (UV) energy. Solar energy travels to the Earth in waves. Fast moving particles from the sun are called the solar wind. They push comet tails out and damage satellites. http://www.solarviews.com/eng/comet.htm

Light and heat waves and 37. What comes from Stars? Light and heat waves and solar wind particles The Earth’s magnetic field Protects the Earth from the solar wind. Solar flares and the solar wind http://www.chabotspace.org/vsc/solar/spaceweather/curriculum/107_Magnetic%20Configuration.pdf

38. Spectra Lines Each element makes a unique emission spectrum Spectral lines tell us which elements are in a star. Continuous Spectrum Emission Spectrum Absorption Spectrum http://csep10.phys.utk.edu/astr162/lect/light/absorption.html

39. Gravity and Fusion are Balanced During the main sequence, there is a balance between the nuclear fusion that wants to expand a star and gravity that wants to crush it.

40. Star Color Shows Temperature Blue stars are young and hot Yellow stars are middle aged and medium Red stars are old and cooler The Sun

41. First Matter After the Big Bang The first element to form after the big bang was Hydrogen The Hindenberg blew up because it was filled with Hydrogen http://www.webelements.com/webelements/elements/text/H/econ.html

42. Creation of Elements Smaller Than Iron Elements from Helium (He) to iron (Fe) are made in stars by nuclear fusion.

Elements larger than Fe are fused together in supernovas. 43. Supernova 2001du Super giant stars end their lives with a huge explosion called a supernova. Elements larger than Fe are fused together in supernovas. http://www.rochesterastronomy.com/snimages/best_img.html

On a clear night you can see about 6,000 stars without a telescope. 44. Stars Seen From Earth On a clear night you can see about 6,000 stars without a telescope. Polaris http://www.bbc.co.uk/science/space/myspace/nightsky/

(45 & 46.) Polaris Polaris is a super giant star that points north. is used by sailors to navigate. http://www.astro.uiuc.edu/~kaler/sow/polaris-t.html

47. Electromagnetic Spectrum All the wavelengths of energy from the sun. Radio Waves, Micro Waves, Infra red, R,O,Y,G,B,I,V Ultra Violet, X-Rays, Gamma Rays

(48 - 50) Waves and Particles from the Sun Energy waves from the sun include: Heat, (IR), Visible light (VIS) and Ultraviolet (UV) light. Particles from the sun called the solar wind push comet tails out and damage satellites. http://www.solarviews.com/eng/comet.htm

Red, Orange, Yellow, Green, Blue, Indigo, Violet (51& 52). Visible Light Red, Orange, Yellow, Green, Blue, Indigo, Violet Low frequency Long Wavelength Low energy High frequency Short Wavelength High energy http://scifiles.larc.nasa.gov/text/kids/Problem_Board/problems/sound/sound_waves2.html

53. The Source of energy for all bio-geo-chemical –cycles on Earth is the sun A powerful M9-class solar storm that unleashed a coronal mass ejection toward Earth in the early hours of Jan. 23, 2012 (GMT). Read more: http://www.foxnews.com/scitech/2012/01/31/with-suns-activity-set-to-diminish-is-global-cooling-coming/#ixzz1lEtainph

bio-geo-chemical cycles on the 54. Energy on the Surface of Earth The sun powers most bio-geo-chemical cycles on the surface of the Earth.

Slide 31 The End