The Initial Observing Plan

It’s all about timing: How long does each orbit take? To answer that, we’ll take pictures — lots of pictures.

As the two components of KIC 9832227 orbit each other, the combined light of the pair seems to vary in brightness. (The two components are so close together that there is no telescope we can build that could separate them; KIC 9832227 will always look like a single star, even in our telescope.) As they go around, at various times in their orbits one of the two may block some of the light from the other; it’s even possible that each of the two stars may have one side slightly hotter (and brighter) than the other side. We’ll take advantage of those differences to measure how long they take to go around each other.

How much change? Other astronomers have seen about a 10% change in the total amount of light received from the pair over the course of a complete 11-hour orbit. That should be pretty easy to measure.

And so the plan is:

• About once a week (depending on weather), observe most of an orbit
• Observing an orbit means taking many pictures of the star through the telescope; ideally, enough pictures to cover an entire 11-hour orbit
• Make each picture a 30-second exposure (so, in an 11-hour cycle, that’s about 60 * 11 minutes * 2 exposures/minute = 1200+ images)
• From each exposure, extract the apparent brightness of KIC 9832227. Plot those numbers and compare to similar plots from other days to determine how long each cycle lasts.

Although the local weather forecasts are somewhat sketchy, maybe we can get our first observing cycle on the night of November 26. Let’s see what happens…