SKY REPORTER: The Search for Habitable Planets

Field of view where NASA’s Kepler mission orbiting observatory is searching for extrasolar planets.
Credit: NASA, Carter Roberts

Like a sharp-eyed lookout reporting from high in an orbiting crow's nest, the Kepler Mission telescope is aimed at a direction in space near where the Solar System is racing at half a million miles per hour. But rather than warning of impending close encounters, Kepler has over the past four years returned evidence that over a hundred planets orbit distant stars across a patchwork of sky in the northern constellations Lyra and Cygnus. The Kepler Mission is especially looking for planets about the size of Earth in so-called “Goldilocks” zones around Sun-like stars. In such regions planets with proper atmospheres could possibly maintain surface temperatures allowing the presence of liquid water, an essential medium for life as we know it.

Recently NASA announced astronomers working with the Kepler observatory had identified additional planets including three that are relatively small, rocky, and orbiting within prime habitability zones around Sun-like stars.  What made the news especially exciting was these worlds are the most similar in size to Earth ever found in such temperate regions. One of them, known as Kepler-62f, has a diameter estimated at 11,000 miles, compared to 7,900 miles for Earth. Kepler-62f orbits at a distance of 66 million miles, taking 267 days to circle yellow star Kepler-62, which is about 70% as massive as the Sun.

During evenings of April and May the Kepler Mission search field, between stars Vega and Deneb that mark corners of the Summer Triangle asterism, is situated in our northeastern sky. Kepler-62 and its family of planets is about seven degrees of arc north of brilliant Vega, brightest star in Lyra. On clear nights you should have no trouble spotting Vega but Kepler-62 is 1,200 light years from us, and about 300,000 times fainter than Vega, therefore it’s best considered in our mind’s eye or through a very large telescope.

The Moon

There is a partial lunar eclipse on April 25; however it’s not visible from North America. During early evening of April 14, the thin crescent Moon is about two degrees from Jupiter in the western sky. The Moon is about five degrees from Saturn during the night of April 26.

Planets

At the start of April Mars, Venus, and Uranus are all too close to the Sun’s position for casual viewing. Mercury is not easily visible low in bright predawn twilight. Venus is beginning a period of evening appearances that lasts through the rest of 2013. However for several months it will be quite low in the western sky during twilight.

Jupiter remains the dominating celestial point of light during evenings of April.

Mars is at conjunction with the Sun on April 17, after which it will be in the early morning sky.

Saturn is at opposition, 180^o of arc from the Sun, on April 27, that night it is above the horizon from sunset to sunrise.