Detecting Exoplanets and Exomoons

By Kimberly Ward-DuongMentor: Dr. Stephen C. Tegler

NAU Dept. of Physics and Astronomy

Arizona/NASA Space Grant Research SymposiumTucson, ArizonaApril 17, 2010

With the Lutz 0.5-Meter Telescope

Exoplanets and Their Transits

Extrasolar Planets 443 systems 71 known to transit Transit/lightcurve relation Tc

Image credit: http://www.astro.virginia.edu/class/oconnell/astr121/

Our project: 1. Observe stars with known

exoplanet transits 2. Analyze transit lightcurves

Transit Timing Variation (TTV)

Periodic changes in Tc

New technique to detect multiple planet systems Ideal for the detection of other Earths, super-Earths

○ None yet discovered by these means!

http://images.iop.org/objects/phw/world/22/3/36/PWbra1_03-09.jpg

Data Collection

Atmospheric Research Observatory at NAU

Barry Lutz Telescope• 0.5-m (20-in) Ritchey-Chrétien

telescope• Apogee CCD Camera• 150-600+ images • 5-7 hours of data per night

Images courtesy of Dr. Stephen Tegler

Data Reduction Process

Creation of detailed analysis procedure

IRAFDifferential photometry

Plot and model lightcurves using MATLAB

WASP-11/HAT-P-10

ResultsWASP-11/HAT-P-10

•Quadratic limb darkening model fit to data (Mandel & Agol 2002)

•Parameters from discovery paper (West et al. 2009)

•Free parameter: Tc

•Standard deviation: 3 mmag

Discussion/Conclusion Observed transit timing variation?

Yes! Best fit model Tc early by 5 minutes

1.8 sec period difference

Possible explanations

More observations needed to verify/explain findings

Long term project plansGoal: Observe 50-100 transits/objectFurther refine modeling specificationsTechnique may also prove useful

for finding an exomoon

Image credit: http://www.astro.virginia.edu/class/oconnell/astr121/

Thank you!

And many thanks to:Dr. Stephen TeglerDr. Nadine Barlow

Ms. Kathleen StigmonArron Shiffer

David TollefsenAlex McCanna

NASA and the Arizona Space Grant Consortium

Questions?Artist’s impression of exoplanet HD 189733b

(Giovanni Tinetti)

(Title slide image credit: STScI artist rendition)