Exoplanet Search Techniques Needs To Be Refined
February 20, 2014

Study Of Exoplanets Not As Mature As The Hype

John P. Millis, Ph.D. for redOrbit.com - Your Universe Online

There is perhaps no field of astronomical research that more captivates our attention than the search for planets outside our solar system. In the last two decades the planet hunting community has exploded, with hundreds of new planets and planet candidates emerging each year.

The holy grail, of course, would be the detection of an Earth-like world. Specifically, astronomers are looking for a planet of similar size to our own, just the right distance from its host star, and with a substantive atmosphere. But these worlds are usually quite distant and small, making them inherently difficult to study.

Consequently, the question becomes how reliable are these results? Can we really image planetary atmospheres and other characteristics with any significance? At least one astronomer is suggesting that our technology has yet to advance enough to take detailed enough data, and perhaps our results are unreliable.

According to Princeton University professor of astrophysical sciences, Adam Burrows, the most widely used methods for studying exoplanet atmospheres – the primary indicator for its suitability of life – were not intended to be used in such ways, rather being designed to image much brighter systems.

“Exoplanet research is in a period of productive fermentation that implies we’re doing something new that will indeed mature,” Burrows told Princeton's Morgan Kelly. “Our observations just aren’t yet of a quality that is good enough to draw the conclusions we want to draw.

“There’s a lot of hype in this subject, a lot of irrational exuberance. Popular media have characterized our understanding as better than it actually is,” he said. “They’ve been able to generate excitement that creates a positive connection between the astrophysics community and the public at large, but it’s important not to hype conclusions too much at this point.”

While our techniques for studying these worlds are rapidly evolving, some of the more specific atmospheric details are not as easily resolved. If we are going to really go after these Earth-like planets, the techniques need to improve.

“The way we study planets out of the solar system has to be radically different because we can’t ‘go’ to those planets with satellites or probes,” Burrows said. “It’s much more an observational science. We have to be detectives. We’re trying to find clues and the best clues since the mid-19th century have been in spectra. It’s the only means of understanding the atmosphere of these planets.”

A longtime exoplanet researcher, Burrows predicted the existence of “hot-Jupiter” planets — gas planets similar to Jupiter but orbiting very close to the parent star — in a paper in the journal Nature months before the first such planet, 51 Pegasi b, was discovered in 1995.

Burrows' recent research is published in the journal Proceedings of the National Academy of Sciences.