Keck at Dawn
Tag: dawn
IRTF at Dawn
Lasing Unto Dawn
Keck in the Dawn
CFHT in the Dawn
Hualālai Dawn
Five Bright Planets in the Dawn
All five planets that are visible to the unaided eye can be found in the dawn for the next few weeks. Jupiter, Saturn, Venus and Mars have been visible in the dawn for some time now. Arriving late to the party is Mercury, just rising out of the glow of dawn. Mercury is headed for maximum elongation on February 7th, rising to 24° ahead of the rising Sun. The line of planets will persist for a week or two after that as Mercury drops back into the glow of dawn after elongation.
Together the five planets neatly outline the ecliptic, the plane of our solar system revealed by simply connecting the dots across the sky. As dawn approaches, but before the start of twilight around 6am, look for the zodiacal light, the bright glow of interplanetary dust also seen along the ecliptic.
New Clues to Ceres’ Bright Spots and Origins
Ceres reveals some of its well-kept secrets in two new studies in the journal Nature, thanks to data from NASA’s Dawn spacecraft. They include highly anticipated insights about mysterious bright features found all over the dwarf planet’s surface.
Credit: NASA/JPL
About the Bright Spots
Ceres has more than 130 bright areas, and most of them are associated with impact craters. Study authors, led by Andreas Nathues at Max Planck Institute for Solar System Research, Göttingen, Germany, write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of magnesium sulfate is familiar on Earth as Epsom salt.
Nathues and colleagues, using images from Dawn’s framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt, they say.
“The global nature of Ceres’ bright spots suggests that this world has a subsurface layer that contains briny water-ice,” Nathues said.
A New Look at Occator
The surface of Ceres, whose average diameter is 584 miles (940 kilometers), is generally dark — similar in brightness to fresh asphalt — study authors wrote. The bright patches that pepper the surface represent a large range of brightness, with the brightest areas reflecting about 50 percent of sunlight shining on the area. But there has not been unambiguous detection of water ice on Ceres; higher-resolution data are needed to settle this question.
Continue reading “New Clues to Ceres’ Bright Spots and Origins”
The Bright Spots on Ceres
As the Dawn spacecraft settles into lower orbits around Ceres the photos of this small world are of ever better resolution. The mysterious bright spots have slowly resolved into an interesting arrangement of multiple spots. Despite many wild claims on YouTube and UFO websites of alien cities or crashed spacecraft, the spots are looking more and more like a set of ice outcroppings. They are still fascinating, if just a bit more ordinary than some would hope.
My bet? Some sort of cryovolcano.
NASA’s Dawn mission captured a sequence of images, taken for navigation purposes, of dwarf planet Ceres on May 16, 2015. The image showcases the group of the brightest spots on Ceres, which continue to mystify scientists. It was taken from a distance of 4,500 miles (7,200 kilometers) and has a resolution of 2,250 feet (700 meters) per pixel.
“Dawn scientists can now conclude that the intense brightness of these spots is due to the reflection of sunlight by highly reflective material on the surface, possibly ice,” Christopher Russell, principal investigator for the Dawn mission from the University of California, Los Angeles, said recently.
Dawn arrived at Ceres on March 6, marking the first time a spacecraft has orbited a dwarf planet. Previously, the spacecraft explored giant asteroid Vesta for 14 months from 2011 to 2012. Dawn has the distinction of being the only spacecraft to orbit two extraterrestrial targets.
The spacecraft has been using its ion propulsion system to maneuver to its second mapping orbit at Ceres, which it will reach on June 6. The spacecraft will remain at a distance of 2,700 miles (4,400 kilometers) from the dwarf planet until June 30. Afterward, it will make its way to lower orbits.
The Dawn Mission Nears Ceres
NASA’s Dawn spacecraft has returned new images captured on approach to its historic orbit insertion at the dwarf planet Ceres. Dawn will be the first mission to successfully visit a dwarf planet when it enters orbit around Ceres on Friday, March 6.
Recent images show numerous craters and unusual bright spots that scientists believe tell how Ceres, the first object discovered in our solar system’s asteroid belt, formed and whether its surface is changing. As the spacecraft spirals into closer and closer orbits around the dwarf planet, researchers will be looking for signs that these strange features are changing, which would suggest current geological activity.
“Studying Ceres allows us to do historical research in space, opening a window into the earliest chapter in the history of our solar system,” said Jim Green, director of NASA’s Planetary Science Division at the agency’s Headquarters in Washington. “Data returned from Dawn could contribute significant breakthroughs in our understanding of how the solar system formed.”
Dawn began its final approach phase toward Ceres in December. The spacecraft has taken several optical navigation images and made two rotation characterizations, allowing Ceres to be observed through its full nine-hour rotation. Since Jan. 25, Dawn has been delivering the highest-resolution images of Ceres ever captured, and they will continue to improve in quality as the spacecraft approaches.