Astronomers are adding 104 worlds to the ever-growing list of known exoplanets, including four that could be Earth-like.
Scientists used Kepler Space Telescope, in addition to Mauna Kea telescopes and other ground-based observatories, to make the discoveries, described as the largest planetary haul under NASA’s K2 mission.
The research team included University of Hawaii staff and students and dozens of collaborators from seven countries.
The planets are identified by the dimming of light caused as they pass in front of their star.
While spotted with Kepler, several observatories on the ground, including the Gemini and Keck telescopes atop Mauna Kea, were used to provide additional analysis of these objects or make confirmations.
“Each has their own instruments,” said Andrew Howard, UH-Manoa astronomer who helped identify the planets. “Some have fantastic imagers and spectrometers that can break apart light in different ways.”
The four potentially Earth-like planets, meaning rocky in composition, are between 20 percent and 50 percent larger than our planet. Each orbit a small star closer than Mercury orbits our sun.
Because that star is far less powerful than our own, two of the planets could be within the habitable range for that solar system. That means they could harbor life.
Howard said that star system is about 400 light years away.
With more powerful telescopes, researchers say they will be able to take a closer look at these planets and understand the makeup of their atmosphere and other factors that could answer the question — is life out there?
That would be done by studying light that passes through those planets’ atmospheres and eventually reaches Earth.
“We can actually determine the presence of individual molecules, water or oxygen, and this technically will become available through observatories like the James Webb Space Telescope and hopefully the Thirty Meter Telescope,” said Evan Sinukoff, a UH-Manoa astronomy graduate student who also participated in the study.
“We’re just scratching the surface.”
Howard said finding exoplanets also helps researchers better understand how solar systems form and why some have multiple planets so close to their star.
“The short answer is we really don’t know. That’s part of the big story,” Howard said. “My view is our solar system is neither common nor rare. It’s part of a broad spectrum and these others are part of the spectrum.”
Email Tom Callis at tcallis@hawaiitribune-herald.com.