SHAFAQNA (Shia International News Association) – A planet discovered outside our solar system is smaller than Mercury, the smallest planet orbiting our sun.
The planet, about the size of the Earth’s moon, is one of three orbiting a star designated Kepler-37 in the Cygnus-Lyra region of the Milky Way.
Using nearly three years of data from NASA’s Kepler spacecraft, astronomers determined Kepler-37’s mass is about 80 percent the mass of our sun. That’s the lowest mass star astronomers have been able to measure using oscillation data for an ordinary star.
Those measurements allowed the main research team to more accurately measure the three planets orbiting Kepler-37, including the tiny Kepler-37b.
Steve Kawaler, professor of physics and astronomy at Iowa State University, was part of a team of researchers who studied the oscillations of Kepler-37 to determine its size. “That’s basically listening to the star by measuring sound waves,” Kawaler says. “The bigger the star, the lower the frequency, or ‘pitch’ of its song.
“Owing to its extremely small size, similar to that of the Earth’s moon, and highly irradiated surface, Kepler-37b is very likely a rocky planet with no atmosphere or water, similar to Mercury,” the astronomers write in a summary of their findings, published in the journal Nature.
“The detection of such a small planet shows for the first time that stellar systems host planets much smaller as well as much larger than anything we see in our own solar system.”
The discovery is exciting because of what it says about the Kepler Mission’s capabilities to discover new planetary systems around other stars, Kawaler says.
The Kepler spacecraft is orbiting the sun carrying a photometer, or light meter, to measure changes in the brightness of thousands of stars. Its primary job is to detect tiny variations in the brightness of the stars within its view to indicate planets passing in front of the star. Astronomers with the Kepler team are looking for Earth-like planets that might be able to support life.
Kepler is sending astronomers photometry data that’s “probably the best we’ll see in our lifetimes,” Kawaler says. This latest discovery shows astronomers “we have a proven technology for finding small planets around other stars.”
That could have implications for some big-picture discoveries.
“While a sample of only one planet is too small to use for determination of occurrence rates,” the astronomers write, “it does lend weight to the belief that planet occurrence increases exponentially with decreasing planet size.”-www.shfaqna.com/English
Source: Iowa State University
SHAFAQNA (Shia International News Association) – In a series of planned maneuvers, NASA's twin GRAIL spacecraft, nicknamed Ebb and Flow, will crash into a crater rim near the moon's North Pole about 2:28 p.m. Pacific time on Monday.
At a news conference on Thursday, scientists involved with the project, which is operated out of the Jet Propulsion Laboratory in La Cañada-Flintridge, spoke about their work's end.
"The mission is almost over, it’s kind of sad to me," said David Lehman, GRAIL project manager.
On Friday morning, he said, engineers at JPL would fire the engines to point the twin crafts, which are about the size of the washer-dryers you'd find in an apartment, toward their mountain target. Following that maneuver, they will turn off the spacecrafts' science instruments.
Over the weekend engineers will conduct a series of additional tests on the probes, and just under an hour before impact, they'll burn the remaining fuel on each craft -- which could take anywhere from 0 to 9 minutes -- in an effort to measure how much fuel remains on board.
"It should help engineers improve mission designs in the future," Lehman said.
Ebb and Flow will approach their final resting positions at a very shallow angle -- perhaps only slightly over one degree -- and should travel at about 3,760 miles per hour when they hit the moon's surface. Ebb will impact first. Flow will follow about 20 seconds later, landing about 25 miles away. Both probes will be destroyed upon impact, the scientists said.
The Gravity Recovery and Interior Laboratory mission, as GRAIL is formally known, took advantage of interactions between Ebb and Flow to measure the lunar gravity field -- a first in planetary science beyond Earth's orbit, as Los Angeles Times reporter Scott Gold recently wrote.
The three-month long, primary mission used the data to compile the "highest-resolution gravity field for any planet in the solar system, including Earth," said principal investigator Maria Zuber of the Massachusetts Institute of Technology in Cambridge, Mass., at Thursday's news conference. (While the moon is not popularly thought of as a "planet," it is considered by scientists to be a planetary body.) Since August, GRAIL has been making further gravity measurements at lower altitudes. The data from that extended mission should become public by the end of May.
Having the high-resolution gravity map helps scientists learn more about lunar composition and, by extension, the makeup and history of other rocky planets and planetary bodies in the solar system, the researchers said. To cite just one example, Zuber noted that the team had learned that the lunar crust is far thinner than scientists had believed, which means the lunar mantle (the layer below the crust) has possibly been exposed by crater impacts. Studying exposed lunar mantle should help planetary scientists understand the Earth's mantle, she said.
Further information about GRAIL findings is available at the mission website, which is maintained by NASA.- www.shfaqna.com/English
SHAFAQNA (Shia International News Association) — NASA partner Sierra Nevada Corporation (SNC) has completed a successful test of the nose landing gear for its full-scale Dream Chaser engineering flight test vehicle. The completed test and an upcoming flight test are part of SNC's Commercial Crew Development Round 2 (CCDev2) agreement with NASA's Commercial Crew Program.
The gear test is an important milestone to prepare for the upcoming approach and landing test of the Dream Chaser Space System later this year. It evaluated the impact the nose landing gear will experience on touchdown in order to ensure a safe runway landing.
SNC is one of seven companies developing commercial crew transportation capabilities to ferry U.S. astronauts to and from low Earth orbit and the International Space Station. The Dream Chaser is the only spacecraft under CCDev2 that is winged and designed to land on a conventional runway. It is designed to carry as many as seven astronauts to space.
"The landing gear system must perform flawlessly, just like the space shuttle orbiter's did, for the safe return of the crew," CCP program manager Ed Mango said. "It's great to see that SNC is building on that experience while developing the Dream Chaser spacecraft."
SNC tested the spacecraft's main landing gear in February. This nose landing gear test completes the milestones leading up to the upcoming approach and landing test, which will complete the CCDev2 partnership.
"This test marks a significant point in the development of the Dream Chaser orbital crew vehicle. As the last milestone before free flight of the Dream Chaser spacecraft, we are now preparing for the approach and landing tests to be flown later this year," said Jim Voss, SNC vice president of space exploration systems and program manager for the Dream Chaser.
All of NASA's industry partners, including SNC, continue to meet their established milestones in developing commercial crew transportation capabilities under CCDev2.—www.shafaqna.com/english