- Associated Press - Saturday, March 11, 2017

NEWARK, Del. (AP) - In astronomy, discoveries are not made overnight.

In 1999, John Gizis, a professor of physics and astronomy at the University of Delaware, discovered one of the most important stars in NASA’s history.

He just didn’t know it until decades later….

There are more than 1 billion trillion stars in the observable universe, scientists estimate, and even within “close” proximity to the earth there are thousands for scientists to study - few are orbited by planets, and even fewer by planets that could conceivably support life.

Yet, somehow, a star discovered by Gizis in 1999, nearly two decades ago, is host to not one, but seven Earth-like planetary objects, NASA recently announced. And it’s only 40 light years, or 235 trillion miles, away.

That’s close enough that it could be captured by the Kepler Telescope.

“I was very excited,” Gizis said of the discovery. “And maybe a little bit jealous, too. Personally, it is an honor to have found something that came out in the long term.”

Though outside our solar system, the system of exoplanets is relatively close to us, NASA says, in the constellation Aquarius.

“It’s fairly close by astronomical standards,” Gizis clarified, “though not the closest star.”

The system is being called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system. Assisted by several ground-based telescopes, including the European Southern Observatory’s Very Large Telescope, NASA’s Spitzer Space Telescope confirmed the existence of two of the planets and discovered five additional ones, increasing the number of known planets in the system to seven.

Three are firmly located in the habitable zone, the area around the parent star most likely to have liquid water. The discovery sets a new record for greatest number of habitable-zone planets found around a single star outside our solar system, according to NASA.

“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington after the discovery. “Answering the question ‘are we alone’ is a top science priority, and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

The star itself was discovered as part of the Two Micron All-Sky Survey (2MASS), funded by NASA and the National Science Foundation, which Gizis participated in as a postdoctoral research associate at the University of Massachusetts at Amherst.

“I was going out there and discovering these nearby stars in order to catalog and use them for future studies,” Gizis said.

The survey was completed with infrared cameras, which let scientists see stars not visible to the naked eye.

Cold and dim, only 0.05 percent the size of our sun, 2MASS J23062928-0502285 was just another dwarf star floating around in space, Gizis said.

“We studied the star a little bit and then moved onto other things,” he said.

At the time, the technology did not exist to quickly and efficiently determine whether or not such stars were orbited by planets.

“If we had known this particular star had these planets and everything happened to be lined up perfectly, we could have done it,” Gizis said, though it would have taken a lot of time, he said, and after all, it was only one star out of hundreds.

“I think it was important this European group developed robotic telescopes so they could look at many stars efficiently,” he said.

“Frankly, we didn’t necessarily expect it to have any planets.”

In contrast to our sun, the TRAPPIST-1 star - classified as an ultra-cool dwarf - is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. In fact, all seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun. The planets also are very close to each other.

That means, if you were standing on one of the planet’s surface, you could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.

The planets may also be tidally locked to their star, which means the same side of the planet is always facing the star, therefore each side is in either perpetual day or night, according to NASA. That means it’s possible they have weather patterns totally unlike those on Earth, such as strong winds blowing from the day side to the night side, and extreme temperature changes.

“The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets,” said Nikole Lewis, co-leader of the Hubble study and astronomer at the Space Telescope Science Institute in Baltimore, Maryland.

NASA’s planet-hunting Kepler space telescope has also been studying the TRAPPIST-1 system, making measurements of the star’s minuscule changes in brightness due to transiting planets - raw data collected by the telescope may be used to determine the physical makeup of the star, and Gizis plans on going through some of it to see if he can contribute anything else to the study of the new system and star.

The Spitzer, Hubble and Kepler telescopes will help astronomers plan for follow-up studies using NASA’s upcoming James Webb Space Telescope, which launches into space in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere, Gizis said. Webb also will analyze planets’ temperatures and surface pressures - key factors in assessing their habitability.

“This kind of planet is what people have been hoping to find with the James Webb Telescope,” Gizis said. If they do have water, oxygen or ozone, “that would make them much more Earth-like than anything we have found before.”


Information from: The News Journal of Wilmington, Del., https://www.delawareonline.com

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