Kepler Space Telescope

Kepler Telescope Bids ‘Goodnight’ with Final Commands

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NASA’s Kepler space telescope discovered thousands of planets outside our solar system, and revealed that our galaxy contains more planets than stars. Credit: CNASAredit: NASA Ames/JPL-Caltech

 

On the evening of Thursday, Nov. 15, NASA’s Kepler space telescope received its final set of commands to disconnect communications with Earth. The “goodnight” commands finalize the spacecraft’s transition into retirement, which began on Oct. 30 with NASA’s announcement that Kepler had run out of fuel and could no longer conduct science. 

Coincidentally, Kepler’s “goodnight” falls on the same date as the 388-year anniversary of the death of its namesake, German astronomer Johannes Kepler, who discovered the laws of planetary motion and passed away on Nov. 15, 1630.

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‘Heartbeat Stars’ Unlocked in New Study

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Written by Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
October 21, 2016 

Heart_Beat_Stars.jpg This artist’s concept depicts ”heartbeat stars,” which have been detected by NASA’s Kepler Space Telescope and others. Image credit: NASA/JPL-Caltech

  

Matters of the heart can be puzzling and mysterious – so too with unusual astronomical objects called heartbeat stars.

Heartbeat stars, discovered in large numbers by NASA’s Kepler space telescope, are binary stars (systems of two stars orbiting each other) that got their name because if you were to map out their brightness over time, the result would look like an electrocardiogram, a graph of the electrical activity of the heart. Scientists are interested in them because they are binary systems in elongated elliptical orbits. This makes them natural laboratories for studying the gravitational effects of stars on each other.

In a heartbeat star system, the distance between the two stars varies drastically as they orbit each other. Heartbeat stars can get as close as a few stellar radii to each other, and as far as 10 times that distance during the course of one orbit.
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ESO Discovers Earth-Size Planet in Habitable Zone of Nearest Star

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This artist’s impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the solar system. The double star Alpha Centauri AB also appears in the image. Credit: ESO/M. Kornmesser

A newly discovered, roughly Earth-sized planet orbiting our nearest neighboring star might be habitable, according to a team of astronomers using the European Southern Observatory’s 3.6-meter telescope at La Silla, Chile, along with other telescopes around the world.

The exoplanet is at a distance from its star that allows temperatures mild enough for liquid water to pool on its surface.

“NASA congratulates ESO on the discovery of this intriguing planet that has captured the hopes and the imagination of the world,” says Paul Hertz, Astrophysics Division Director at NASA Headquarters, Washington. “We look forward to learning more about the planet, whether it holds ingredients that could make it suitable for life.”

The new planet circles Proxima Centauri, the smallest member of a triple star system known to science fiction fans everywhere as Alpha Centauri. Just over 4 light-years away, Proxima is the closest star to Earth, besides our own sun.

“This is really a game-changer in our field,” said Olivier Guyon, a planet-hunting affiliate at NASA’s Jet Propulsion Laboratory, Pasadena, California, and associate professor at the University of Arizona, Tucson. “The closest star to us has a possible rocky planet in the habitable zone. That’s a huge deal. It also boosts the already existing, mounting body of evidence that such planets are near, and that several of them are probably sitting quite close to us. This is extremely exciting.”

The science team that made the discovery, led by Guillem Anglada-Escudé of Queen Mary University of London, will publish its findings Aug. 25 in the Journal Nature in a 33-page paper titledA terrestrial planet candidate in a temperate orbit around Proxima Centauri. The team traced subtle wobbles in the star revealing, the presence of a star-tugging planet.

They determined that the new planet, dubbed Proxima b, is at least 1.3 times the mass of Earth. It orbits its star far more closely than Mercury orbits our sun, taking only 11 days to complete a single orbit — a “year” on Proxima b.


Long list of unknowns

The stunning announcement comes with plenty of caveats. While the new planet lies within its star’s “habitable zone” — a distance at which temperatures are right for liquid water — scientists do not yet know if the planet has an atmosphere.

It also orbits a red-dwarf star, far smaller and cooler than our sun. The planet likely presents only one face to its star, as the moon does to Earth, instead of rotating through our familiar days and nights. And Proxima b could be subject to potentially life-extinguishing stellar flares.

“That’s the worry in terms of habitability,” said Scott Gaudi, an astronomy professor at Ohio State University, Columbus, and JPL affiliate credited with numerous exoplanet discoveries. “This thing is being bombarded by a fair amount of high-energy radiation. It’s not obvious if it’s going to have a magnetic field strong enough to prevent its whole atmosphere from getting blown away. But those are really hard calculations, and I certainly wouldn’t put my money either way on that.”

Despite the unknowns, the discovery was hailed by NASA exoplanet hunters as a major milestone on the road to finding other possible life-bearing worlds within our stellar neighborhood.

“It definitely gives us something to be excited about,” said Sara Seager, a planetary science and physics professor at the Massachusetts Institute of Technology, Cambridge, and an exoplanet-hunting pioneer. “I think it will definitely motivate people to get moving.”


‘Not completely unexpected’

Statistical surveys of exoplanets — planets orbiting other stars — by NASA’s Kepler space telescope have revealed a large proportion of small planets around small stars, she said.

The Kepler data suggest we should expect at least one potentially habitable, Earth-size planet orbiting M-type stars, like Proxima, within 10 light-years of our solar system.

So the latest discovery was “not completely unexpected. We’re more lucky than surprised,” Seager said. But it “helps buoy our confidence that planets are everywhere.”

It’s especially encouraging for upcoming space telescopes, which can contribute to the study of the new planet. The James Webb Space Telescope, launching in 2018, may be able to follow-up on this planet with spectroscopy to determine the contents of its atmosphere. NASA’s Transiting Exoplanet Survey Satellite (TESS) will find similar planets in the habitable zone in the stellar backyard of our solar system in 2018.

One of TESS’s goals is to find planets orbiting nearby M-dwarf stars like Proxima Centauri.

“It’s great news just to know that M-dwarf planets could be as common as we think they are,” Seager said.

Another possible inspiration Proxima b could reignite: the admittedly far-off goal of sending a probe to another solar system.

Bill Borucki, an exoplanet pioneer, said the new discovery might inspire more interstellar research, especially if Proxima b proves to have an atmosphere.

Coming generations of space and ground-based telescopes, including large ground telescopes now under construction, could yield more information about the planet, perhaps inspiring ideas on how to pay it a visit.

“It may be that the first time we get really good information is from the newer telescopes that may be coming online in a decade or two,” said Borucki, now retired, a former principal investigator for Kepler, which has discovered the bulk of the more than 3,300 exoplanets found so far.

“Maybe people will talk about sending a probe to that star system,” Borucki said. “I think it does provide some inspiration for an interstellar mission, because now we know there is a planet in the habitable zone, probably around the mass of Earth, around the closest star. I think it does inspire a future effort to go there and check it out.”

To read the ESO press release, visit: http://www.eso.org/public/news/eso1629/?lang

To learn more about NASA’s Exoplanet Program, visit: http://exoplanets.nasa.gov

NASA Telescopes Detect Jupiter-Like Storm on Small Star

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This illustration shows a cool star, called W1906+40, marked by a raging storm near one of its poles. Image credit: NASA/JPL-Caltech

 

Astronomers have discovered what appears to be a tiny star with a giant, cloudy storm, using data from NASA’s Spitzer and Kepler space telescopes. The dark storm is akin to Jupiter’s Great Red Spot: a persistent, raging storm larger than Earth.

“The star is the size of Jupiter, and its storm is the size of Jupiter’s Great Red Spot,” said John Gizis of the University of Delaware, Newark. “We know this newfound storm has lasted at least two years, and probably longer.” Gizis is the lead author of a new study appearing in The Astrophysical Journal.

While planets have been known to have cloudy storms, this is the best evidence yet for a star that has one. The star, referred to as W1906+40, belongs to a thermally cool class of objects called L-dwarfs. Some L-dwarfs are considered stars because they fuse atoms and generate light, as our sun does, while others, called brown dwarfs, are known as “failed stars” for their lack of atomic fusion.

The L-dwarf in the study, W1906+40, is thought to be a star based on estimates of its age (the older the L-dwarf, the more likely it is a star). Its temperature is about 3,500 degrees Fahrenheit (2,200 Kelvin). That may sound scorching hot, but as far as stars go, it is relatively cool. Cool enough, in fact, for clouds to form in its atmosphere.

“The L-dwarf’s clouds are made of tiny minerals,” said Gizis.

Spitzer has observed other cloudy brown dwarfs before, finding evidence for short-lived storms lasting hours and perhaps days.

In the new study, the astronomers were able to study changes in the atmosphere of W1906+40 for two years. The L-dwarf had initially been discovered by NASA’s Wide-field Infrared Survey Explorer in 2011. Later, Gizis and his team realized that this object happened to be located in the same area of the sky where NASA’s Kepler mission had been staring at stars for years to hunt for planets.

Kepler identifies planets by looking for dips in starlight as planets pass in front of their stars. In this case, astronomers knew observed dips in starlight weren’t coming from planets, but they thought they might be looking at a star spot — which, like our sun’s “sunspots,” are a result of concentrated magnetic fields. Star spots would also cause dips in starlight as they rotate around the star.

Follow-up observations with Spitzer, which detects infrared light, revealed that the dark patch was not a magnetic star spot but a colossal, cloudy storm with a diameter that could hold three Earths. The storm rotates around the star about every 9 hours. Spitzer’s infrared measurements at two infrared wavelengths probed different layers of the atmosphere and, together with the Kepler visible-light data, helped reveal the presence of the storm.

While this storm looks different when viewed at various wavelengths, astronomers say that if we could somehow travel there in a starship, it would look like a dark mark near the polar top of the star.

The researchers plan to look for other stormy stars and brown dwarfs using Spitzer and Kepler in the future.

“We don’t know if this kind of star storm is unique or common, and we don’t why it persists for so long,” said Gizis.

NASA’s Ames Research Center in Moffett Field, California, manages the Kepler and K2 missions for NASA’s Science Mission Directorate. JPL managed Kepler mission development. Ball Aerospace & Technologies Corp. operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

JPL manages the Spitzer Space Telescope mission for NASA. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech.

Caltech manages JPL for NASA.

For more information about Kepler and Spitzer visit: http://www.nasa.gov/kepler ohttp://www.nasa.gov/spitzer