1. Searching for White Dwarf Exoplanets: WD 2359-434 Case Study 1

2. Bruce Gary, Arizona 14-inch T.G. Tan, Australia 12-inch Ivan Curtis, Australia 11-inch Paul Tristram, New Zealand 24-inch Akihiko Fukui, Japan ( ” ) 2

3. Background PAWM (Pro-Am White dwarf Monitoring), 2011 25 amateurs, 46 WDs, no exoplanet transits However, 3 WDs were variable (surprise) WD 2354-434 was the most interesting WDs are small (same size as Earth) Hot Jupiters are much bigger, & can orbit close Therefore, big planets can reflect WD light and produce variations 3

4. Example Light Curve 4

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7. Starspot can explain observed variation 7

8. But so can an orbiting exoplanet Planet radius = 1.23 x Jupiter Orbit distance = 0.0042 a.u. (for P = 2.7 hrs) Orbit inclination close to edge-on Slightly too close for “habitable zone” 8

9. Follow-Up Observations Needed Radial velocity (to see if hypothetical exoplanet is on far side when brightest) Spectroscopy to check idea of 1) Lyman-alpha emission is coming from planet atmosphere & 2) convection bringing He to surface (e.g., never-before seen spot) All of above require professional hardware 9

10. Conclusions Discovering exoplanets around WDs is within reach of amateurs! But professional collaboration (follow-up) will be needed. 10