Goal: To learn about the Kepler Mission and the Transit Method Objectives: To learn about the basics of the spacecraft To understand Mission goal To learn the reasoning about some of its quirks To explore what we have found so far from Kepler To understand the transit/eclipse method

Launched 2009 March 6, 10:49 pm EST. https://www.youtube.com/watch?v=A1pKRoUk-A4

NGC 6791 Since in space can measure brightness very accurately

Field of View 100,000 stars for Kepler to constantly monitor for 3.5 years

Actual images Black = star

Quirks Spacecraft slowly trails earth in orbit Spacecraft “rolls” every 3 months Looks at a large field of view (about 15 degrees) all at once

Transit When a planet passes in front of a star it partially eclipses the star. A solar eclipse for example occurs when the moon blocks the sun Since planets are small they only block a small portion of the star

We can tell: Just like before with the wobble method we can determine: Orbital period Orbital distance Mass

Difficulties Sunspots can again pose a problem Binary stars Stellar Flares Other random activity Planet has to have orbital plane that makes it pass in front of the star (very limiting) First one detected Nov, 1999 (discovered using wobble). 2nd was 2002 (first discovered using transit - OGLE-TR-56 b)

Initial findings

Much more accurate!

Candidate vs confirmed Since NASA wants to see 3 transits per planet. Found hot Jupiters in months. Objects in Mercury orbits in about a year Planets in Earth like orbits in 3 years.

Expectations: 100,000 stars If 10% have planets then 10,000 star systems However, since Kepler uses transits to find planets only 0.5% of the systems will be detectable. That gives 500 expected systems to observe.

Actual: Candidate exoplanets: 4,706 Confirmed exoplanets: 1,039 Confirmed exoplanets less than twice Earth-size in the habitable zone: 12 So this implies that the % of stars with planets is somewhere between 20% and 80%

What Kepler will not be able to do Observe the atmosphere. We are still finding the planets indirectly. The parent stars are too far away and too dim to do detailed analysis from the ground. Kepler does not take spectrums…

Conclusion We have learned about how to use gravitational lensing as a tool. We have examined the complications with this style of observation.