Good Work, Everybody!

Thinking Skills Asking questions is a really important skill that you've been working on. It will help you: Effectively figure out what people are trying to tell you Increase your understanding...Not just in class, but in all parts of your life!

Thinking Skills Explaining your ideas clearly is another great skill you've practiced today.

Transiting Planets You've each spent a lot of time investigating different aspects of these planetary systems. Right now astronomers can't look at planets directly because they are so far away, and the stars they orbit are so bright. Instead they look at the way the light from the host star changes over time to learn about the planets.

What is a Transit Lightcurve? Cool movie with lightcurve and planet transiting A graph describing how the light seen from a star changes its brightness over time when a planet passes in front of it (transits).

Transit Lightcurves Tell Us About......Size of the planet: A small planet blocks a small amount of light, creating a shallower dip. Time or angle Amount of light

Transit Lightcurves Tell Us About......Size of the planet: A small planet blocks a small amount of light, creating a shallower dip. A larger planet will block more light, creating a deeper dip. Time or angle Amount of light Time or angle Amount of light

Transit Lightcurves Tell Us About......Inclination of the planet's orbit: A planet aligned with us will cross the widest part of the star, causing a wider dip. Amount of light Time or angle

Transit Lightcurves Tell Us About......Inclination of the planet's orbit: A planet aligned with us will cross the widest part of the star, causing a wider dip. A planet slightly off- axis will cross a narrower part of the star, causing a narrower dip. Amount of light Time or angle

Transit Lightcurves Tell Us About......Inclination of the planet's orbit: A planet more than a little inclined will not transit at all. If you see a dip, the planet's orbit cannot be very inclined. Time or angle Amount of light

Other Properties that Affect Transit Lightcurves:...Size of the star: A planet crossing a big star travels a longer distance in front of the star and blocks a smaller fraction of the star's light, creating a wider and shallower dip. Time or angle Amount of light

Other Properties that Affect Transit Lightcurves:...Size of the star: A planet crossing a small star travels a shorter distance in front of the star and blocks a larger fraction of the star's light, creating a narrower and deeper dip. Time or angle Amount of light Time or angle Amount of light

Other Properties that Affect Transit Lightcurves:...Brightness of the star: A brighter star gives off more light. This can make the transit appear deeper... but in fact the fraction of the star's light blocked by the planet does NOT depend on the size of the star. Bright Star Faint Star Amount of light Time or angle vs.

Transit Lightcurves Tell Us About......Whether the planet has moons or rings Anything that makes a planet non-spherical will create extra dips/features in the light curve. Time or angle Amount of light Time or angle Amount of light

Transit Lightcurves Also Tell Us About......The time it takes for the planet to orbit once around the star (period) …Anything else?

Transit Lightcurves Do NOT Tell Us About......The color of the planet...The color of the star …Anything else? Note: we CANNOT tell the distance between the star and the planet from the depth of the light curve, but we CAN tell the distance from the period!!

Transit Missions Remember, astronomers are doing this right now. In the next few years, technology will allow astronomers on the ground to study light from the planets themselves! Look for reports of new planet discoveries in the news – now you know how they're done.