A recent visit to the Johannes Kepler University in Linz, Austria (albeit not for a conference related to astronomy) inspired me to write an article about NASA’s Kepler telescope and it’s search for extra solar planets.
Who was Kepler?
Any talk about the Kepler mission should mention the man it was named after. Johannes Kepler was a mathematician, astronomer and astrologer born in Germany in the 16th Century. He is most well known for his planetary laws of motion which explain the elliptical shapes of orbits and the speed of planets at different distances from their star. These laws also formed an early basis for Isaac Newtons universal law of gravitation.
The kepler mission is one focused on the search for extrasolar planets. The telescope in itself is a 0.95m telescope which aims to detect light rather than produce images like traditional telescopes. It has an unnaturally large field of view which allows it to observe around 100,000 stars for the life of the mission. Although some of the measurements could be made on earth the telescope is space based to allow continuous monitoring of stars so day/night cycles have no effect, also atmospheric and seasonal effects have no impact on the measurements and the accuracy of the observations.
Aims and Methods
The main aim of the Kepler Mission is to find planets outside of our solar system it does that by looking for the transit of planets across the face of a star it is orbiting. The scientific analysis of these planets relate to another aim by which the mission is to explore the structure and diversity of planetary systems. By surveying large numbers of stars the mission can also determine the percentage of terrestrial and larger planets that reside in a habitable zone, it can determine size distributions of the size and shapes of planets, estimate number of planets in multiple star systems.
By observing the intensity of light coming from distant stars the mission looks for reductions in the intensity which would be inherent with a planet passing between the star and the telescope. The mission looks for periodic reductions in this signal which is associated with the orbits of planets which, if like our solar system would be of a regular orbital period. The image above shows two examples of light curves used in the transit method, the above shows a regularly orbiting planet shown by the dips in intensity, the second shows potentially two planets in a system.
Since launch the Kepler observatory has made around 61 confirmed discoveries with many more light curves being analysed daily for potential candidates. Out of these discoveries some have received reports in the media due to their potential scientific impacts and interesting properties.
Kepler 22-b was a significant discovery made in December 2011 which was that of a nearly Earth sized planet. Prior to this discovery a number of Earth sized planets had been discovered however, to make things different Kepler 22-b was discovered in what is deemed the habitable zone around it’s star making it a true Earth like planet. Another, that of Kepler 16-b was reported due to it being the first planet orbiting a 2 star system to be seen. With this many drew comparisons between it and the planet of Tatooine from Star Wars!
The Future of Kepler
Kepler space observatory is very much still in it’s infancy so many many more discoveries of vastly different planetary systems are sure to be made. However, one thing that is holding back discoveries is the sheer number of star systems being observed and the limited amount of astronomers on the project. There is a way though in which the public can help. A website has been set up called Planet Hunters which shows light curves and encourages the public to help look for planetary candidates by marking on them variations in the light curves, so give it a go at the link below.