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NASA’s Dawn mission has gone into orbit around Ceres, the largest object in the Solar System between Mars and Jupiter.

A signal from the satellite confirming Dawn’s status was received by ground stations at 13:36 GMT.

Ceres is the first of the dwarf planets to be visited by a spacecraft.

Scientists hope to glean information from the object that can tell them about the Solar System’s beginnings, four and a half billion years ago.

Dawn has taken 7.5 years to reach its destination. Its arrival has seen it pass behind the dwarf to its “dark side”.

Over the next month, controllers will re-shape the orbit to get it ready to begin the prime science phase in late April.

Over time, the intention is to progressively lower the orbit until the probe is just a few hundred km above the surface. By that stage, it will be returning very high resolution pictures.Dawn mission Ceres orbit

“We feel exhilarated,” said Chris Russell, the mission’s principal investigator from the University of California, Los Angeles (UCLA).

“We have much to do over the next year and a half, but we are now on station with ample reserves, and a robust plan to obtain our science objectives.”

The satellite has turned up at Ceres having previously visited asteroid Vesta.

Both objects reside in the belt of rocky debris that circles the Sun beyond Mars.

Researchers think Ceres’ interior is dominated by a rocky core topped by ice that is then insulated by rocky lag deposits at the surface.

A big question Dawn mission hopes to answer is whether there is a liquid ocean of water at depth. Some models suggest there could well be.

The evidence will probably be found in Ceres’ craters which have a muted look to them. That is, the soft interior of Ceres has undoubtedly had the effect of relaxing the craters’ original hard outline.

One big talking point has dominated the approach to the object: the origin and nature of two very bright spots seen inside a 92km-wide crater in the Northern Hemisphere.

The speculation is that Ceres has been struck by something, exposing deeply buried ices.

These will have vaporized on the airless world, perhaps leaving behind highly reflective salts.

The Dawn mission is expected to work at the dwarf planet for at least 14 months.

While Dawn takes the honor of being the first spacecraft to visit a dwarf planet, the next opportunity comes very quickly.

NASA’s New Horizons probe is due to make a close flyby of Pluto in July.

This far-more distant world was demoted from full planet to dwarf status at an international astronomy meeting in 2006.

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Astronomers have obtained an important first look at the dwarf planet Makemake – finding it has no atmosphere.

One of five such dwarfs in our Solar System including former planet Pluto, Makemake had until now eluded study.

But in April 2011, it passed between the Earth and a distant star, and astronomers used seven telescopes to study how the star’s light was changed.

A report in Nature outlines how they unpicked Makemake’s size, lack of atmosphere, and even its density.

Few battles in the astronomy community are as fierce as the one surrounding the demotion of the planet Pluto from planet status in 2006 to one of what the International Astronomical Union then dubbed “dwarf planets”.

Pluto shares the category with four other little worlds: Ceres, Haumea, Eris and Makemake.

Ceres, as the only inner Solar System dwarf, has been analyzed directly with telescopes.

Astronomers have obtained an important first look at the dwarf planet Makemake finding it has no atmosphere

Astronomers have obtained an important first look at the dwarf planet Makemake finding it has no atmosphere

The far more distant Eris and Haumea have both been analyzed separately in the same kind of “occultation” that has now given clues as to Makemake’s makeup.

Haumea was shown to be icy like Pluto, while Eris added to Pluto’s indignities by ousting it as the largest dwarf.

Now Makemake has come under scrutiny by an international team led by Jose Luis Ortiz of the the Andalucian Institute of Astrophysics in Spain, making use of seven different telescopes across Brazil and Chile.

They watched as the dwarf planet blocked the light of distant star Nomad 1181-0235723, only for about one minute.

The dwarf was known to be about two-thirds the size of Pluto, but the team put the measurement on a firmer footing, measuring it to be not quite spherical – about 1,430 km across in one direction and 1,500 km across the other.

The team estimates that Makemake has a density of 1.7 grams per cubic centimetre (similar to that of Pluto, but still less than a third that of Earth) – but the key test was that of the dwarf planet’s atmosphere.

“As Makemake passed in front of the star and blocked it out, the star disappeared and reappeared very abruptly, rather than fading and brightening gradually,” said Dr. Jose Luis Ortiz.

“This means that the little dwarf planet has no significant atmosphere. It was thought that Makemake had a good chance of having developed an atmosphere – that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies.

“Finding out about Makemake’s properties for the first time is a big step forward in our study of the select club of icy dwarf planets.”

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