What's Up? A Slew of Exoplanet Discoveries

Welcome back to What's Up?

As NASA's Kepler spacecraft continues to look for tell-tale clues of planets circling distant stars, reports of confirmed planet discoveries are slowly trickling in. Just in the last month, NASA announced that Kepler had discovered its first multiple planet system.

Kepler finds planets by detecting a dip in brightness as the planet passes in front of its star.

In this first multiple planet system, there are two planets orbiting the same star with a third unconfirmed planet called a “super-Earth.” This super-Earth is not likely to be very Earth-like, being a few times the mass of the Earth and orbits around its star in barely more than 38 hours!

Kepler is NASA's main instrument for discovering planets around other stars. It will stare at the same star field in the constellation Cygnus, the swan, for at least three and a half years. Out of the millions of stars in its field of view, Kepler will continuously monitor 100,000 of them.

Where Kepler will watch for
exoplanets. Click to enlarge.

The spacecraft is named after Johannes Kepler, who is best known for figuring out that the planets in our solar system have ellipse shaped (egg shaped) orbits around the Sun.

Scientists working with Kepler are very cautious about announcing new discoveries and always double or triple check everything. Right now there are over 700 possible planets from just a few months of data collection. Even if half of these are planets, it will nearly double the number of currently known extrasolar planets.

Among these candidates are many smaller planets and possible Earth sized planets. Although there may be many small Earth-sized worlds, the data needs to be checked by other telescopes for false alarms.

A completely separate team of astronomers working with the European Southern Observatory have discovered the richest exoplanet system known. Circling around the creatively named star, HD 10180, are at least five Neptune sized worlds.

This busy planetary system was discovered by carefully watching the starlight for blue shifting or red shifting, caused by the star being tugged towards and away from us by an unseen planet orbiting the star.

The astronomers also reported that there are two “fuzzier” signals present. The lead researcher, Dr. Christophe Lovis says he is “99%” certain that these two other planets are indeed there.

One of these uncertain exoplanets appears to be only 1.4 Earth masses. If confirmed, it will be the least massive exoplanet yet discovered.

Technology for detecting planets around other stars is still in its infancy, and yet there are over 400 currently known exoplanets and now there is a single star with as many as seven planets orbiting it!

An artists depiction of a planet around another star.

Future missions, like the James Webb Space Telescope, will have the ability to directly image some of these planets. By looking the colours reflected by the planet, astronomers will be able to figure out the composition of these planets' atmospheres.

Until then, let's see what's up in this month's sky.

The new Moon will be on Sept. 8 this month and will swell to become a full Moon on Sept. 23.

Jupiter will be at opposition (closest point to Earth) on Sept. 21. This is the best time to view the king of the planets. It will be the brightest star-like object rising in the east just after sunset.

Venus will be low near the western horizon and is the brightest object in the night sky (other than the Moon), while Mars will appear as a reddish star off to the side.

Autumnal Equinox, also known as the first day of Autumn, is on Sept. 23.

The monthly meeting of the Athena Community Astronomy Club will be on Sept. 26, the last Sunday of the month. The meeting starts at 7pm and ends at 9pm. Guests are always welcome.

Until next month, just look up!

Hey Kids...
Did you know that you can help choose the space shuttle's wake-up music? If you go on the internet and go to "songcontest.nasa.gov", you can vote on which song you would like the astronauts to wake up to on the next Space Shuttle mission. If you feel really creative, you could even write your own song, and possibly have the astronauts on the last Space Shuttle mission listen to it. Imagine being a music star almost literally among the stars.