Terrestrial (rocky) planets are prime targets in the quest to find life because some of them might be geologically and atmospherically similar to Earth. While this is an exciting discovery, it's still not confirmed - it will take more time on the Hubble Space Telescope to confirm this remarkable find.
The possible moon was documented by Kepler, the powerhouse planet-hunting space telescope, when it cast a shadow by crossing in front of a star. The researchers' investigations showed that the HST-recorded transit of Kepler-1625b occurred almost 80 minutes earlier than expected, a pattern suggesting the presence of transit timing variations, or TTVs, which are among the first proposed methods to confirm the presence of exomoons. In some configurations, that tug will be in the direction of the planet's orbit around its star, causing the transit to occur sooner than expected.
The finding may lead to theories on the formation of moons being revisited, David Kipping, of Columbia University in NY, said. The data suggested that a Jupiter-sized planet, Kepler-1625b, may be orbited by an exomoon. The dimmings seemed to show additional dips in brightness, as if another body was tagging along as the planet crossed the star.
With that data in hand, they first repeated their former analysis.
"The search for life as we know it starts with water", Mayorga said. The new results are presented in the journal Science Advances. In this study, they analysed 284 light curves from the Kepler satellite of planet-hosting stars that were considered to be plausible candidates for systems containing exomoons. Or perhaps, like Earth's moon, it is a product of its planet, formed in some catastrophic collision.
The discovery, detailed by researchers yesterday, was a surprise, and not because it showed that moons exist elsewhere ― they felt it was only a matter of time for one to be found in another star system. It makes sense, Teachey said, that the first moon scientists spot would also be a giant.
Hubble's data, along with fine-tuned data from Kepler, strengthened the case for claiming Kepler-1625b had an exomoon.
It's not like the exomoon in "Avatar" or Endor from "Star Wars", Teachey said, "but going forward, I think we're opening doors to finding worlds like that". "It's exciting to see the hunt for the first exomoon continue, and with what would be a shockingly large moon", wrote Sara Seager, an astrophysicist at the Massachusetts Institute Technology in Cambridge who was not involved with the work, in an email. In addition, the ideal candidate planets hosting moons are in large orbits, with long and infrequent transit times. So the candidate body probably coalesced from a circumplanetary disk, as the big Galilean moons of Jupiter did.
Artist's impression of the exoplanet and exomoon transiting the star. "If they see what we see, I expect some people will be convinced and other people will be skeptical. While most of these moons orbit Saturn and Jupiter, which are outside the Sun's habitable zone, that may not be the case in other solar systems", said Stephen Kane, an associate professor of planetary astrophysics and a member of the University of California Riverside's Alternative Earths Astrobiology Center.
Those observations could come from another go-round with Hubble, or they could come from NASA's James Webb Space Telescope, which is due for launch in 2021.