Extrasolar Planets: June 2017

Since the mid-1990s, when the first planet around another Sun-like star was discovered, astronomers have been amassing what is now a large collection of exoplanets -- nearly 3,500 have been confirmed so far.

With continued improvement in telescope sensitivity and observational techniques, the search for rocky planets in stellar habitable zones is entering an exciting era. With so many exoplanetary systems available for follow-up observations to find potentially habitable planets, one needs to prioritise the ever-growing list of candidates.

A team of astronomers at the University of Chicago and Grinnell College seeks to change the way scientists approach the search for Earth-like planets orbiting stars other than the sun.

In the last decade, over a million stars were monitored to detect transiting planets. Manual interpretation of potential exoplanet candidates is labor intensive and subject to human error, the results of which are difficult to quantify.

By detecting light from extrasolar planets,we can measure their compositions and bulk physical properties. The technologies used to make these measurements are still in their infancy, and a lack of self-consistency suggests that previous observations have underestimated their systemic errors.

Kepler-452b is currently the best example of an Earth-size planet in the habitable zone of a sun-like star, a type of planet whose number of detections is expected to increase in the future.

In a unique experiment, scientists used NASA's Hubble Space Telescope to study two "hot Jupiter" exoplanets. Because these planets are virtually the same size and temperature, and orbit around nearly identical stars at the same distance, the team hypothesized that their atmospheres should be alike. What they found surprised them.