During the Perseid meteor shower, second-largest asteroid 2 Pallas passed close to the southeast of globular cluster Messier 15 in the constellation of Pegasus. The minor planet still lies in the vicinity of this beautiful deep-sky object, reaching opposition on 20 August — here’s our in-depth guide to Pallas at its best.
By tracking subtle changes in the motion of NASA’s Dawn spacecraft, scientists have mapped the variations in Ceres’ gravity for the first time, providing clues to the dwarf planet’s internal structure. The new data suggest that Ceres has a weak interior, and that water and other light materials partially separated from rock during a heating phase early in its history.
Ceres is covered in countless small, young craters, but none are larger than 175 miles (280 kilometres) in diameter. To scientists, this is a huge mystery, given that the dwarf planet must have been hit by numerous large asteroids during its 4.5 billion-year lifetime. Where did all the large craters go?
An international team of astronomers have discovered a new dwarf planet orbiting beyond Neptune. The object is roughly 435 miles in size, moving in a 700-year orbit that takes it more than 120 times further from the Sun than Earth. Designated 2015 RR245, it was found using the Canada-France-Hawaii Telescope on Maunakea, Hawaii.
Scientists with NASA’s Dawn mission have identified permanently shadowed regions on the northern hemisphere of dwarf planet Ceres. Most of these areas likely have been cold enough to trap water ice for a billion years, suggesting that ice deposits could exist there now. These permanently shadowed regions could be colder than those on Mercury or the Moon.
Following its historic first-ever flyby of Pluto, NASA’s New Horizons mission has received the green light to fly onward to an object deeper in the Kuiper Belt, known as 2014 MU69. The spacecraft’s planned rendezvous with the ancient object — considered one of the early building blocks of the solar system — is 1 January 2019.
The brightest area on Ceres, located in the mysterious Occator Crater, has the highest concentration of carbonate minerals ever seen outside Earth, according to a new study from scientists on NASA’s Dawn mission. The results suggest that liquid water may have existed beneath the surface of Ceres in recent geological time.
NASA’s New Horizons spacecraft spied extensional faults on Pluto, a sign that the dwarf planet has undergone a global expansion possibly due to the slow freezing of a sub-surface ocean. A new analysis by Brown University scientists bolsters that idea, and suggests that ocean is likely still there today.
In the latter part of June, Pluto is best seen low in the southern UK sky around 2am local time and reaches opposition on 7 July. The dwarf planet passes less than 1/20th of a degree south of naked-eye star pi (π) Sagittarii on 26—27 June in the deep twilight of the UK, but Southern Hemisphere observers will have the best views.
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