Variable stars are simply stars that change in brightness over time. Stars such as Mira, as seen on the HOME page, have patterns of luminous fluctuations over periods of time. Certain stars are deemed variable stars because they have planets orbiting them. A star's brightness is called it's magnitude. When the planet crosses in front of the star, it causes the star to dim. This is a way of detection called the "transit method".
The magnitude of the star is recorded over a period of time; when the magnitude is at its lowest, it is at its initial magnitude. When the magnitude is higher, there is a planet crossing in front of it from the observer's point of view. The magnitude scale runs backwards: the higher the number, the dimmer the light. When a planet passes in front of a star, it is called a transit. In this study, the star TrES-3 and the planet TrES-3b was observed; it takes about 31 hours for the planet, to make a full orbit around TrES-3. It's transit lasts about 84 minutes.
The magnitude of the star is recorded over a period of time; when the magnitude is at its lowest, it is at its initial magnitude. When the magnitude is higher, there is a planet crossing in front of it from the observer's point of view. The magnitude scale runs backwards: the higher the number, the dimmer the light. When a planet passes in front of a star, it is called a transit. In this study, the star TrES-3 and the planet TrES-3b was observed; it takes about 31 hours for the planet, to make a full orbit around TrES-3. It's transit lasts about 84 minutes.