Chiron, minor planet, discovered 1977

Chiron, a minor planet between Saturn and Uranus, was discovered November 1, 1977, by Charles Kowal.  It was the first of a class of objects known as centaurs, astral bodies orbiting between the asteroid belt and the Kuiper Belt.  

It also has a classification as a comet, 95P/Chiron.

It has a radius of about 107.8 + 5km and rotates about every 6 hours.  It orbits the sun about every 50.5 years.

In February 1988, it brightened by 75%, which is typical of comets but not asteroids.  In April 1989, it developed a cometary coma, and in 1993, it formed a tail.  

Dawn, NASA's mission to the Asteroid Belt, comes to an end

Dawn, the little spacecraft that could, has ended its mission into the asteroid belt.  Launched in September 2007, it is the first probe to orbit one celestial body and then leave to orbit another one.  Dawn arrived at Vesta in July 2011 and studied the protoplanet for 14 months.

Dawn left Vesta and traveled to Ceres, arriving in March 2015, where it remains.  It missed several scheduled communications and NASA has concluded it has run out of hydrazine, the fuel that helps the craft keep its antennae pointed toward Earth and its solar panels to the sun.

Its mission lasted three years longer than anticipated.

Dawn achieves orbit around protoplanet Vesta, 2011

NASA's Dawn probe, launched in 2007, entered orbit around the "protoplanet" Vesta in the asteroid belt July 16, 2011.  It is the first spacecraft to visit Vesta and Ceres, a dwarf planet where Dawn is currently orbiting.

A protoplanet is a large planet embryo that originated...you know what?  Here's the description on Wikipedia and you can figure it out, because I sure can't.

Vesta is the second-largest and second-most-massive object in the asteroid belt behind Ceres.  It has an elliptical shape with diameters from 550 km x 462 km and its year is 3.6 Earth-years.

In September 2012, Dawn left Vesta and is now in orbit around Ceres.

Pioneer 11 launched 1973

Pioneer 11, interplanetary probe, was launched by NASA April 6, 1973.  It studied the asteroid belt, Jupiter and Saturn.  Pioneer 11 passed through the asteroid belt in April 1974 and encountered Jupiter December 3, 1974.

It flew by Saturn September 1, 1979, becoming the first probe to encounter the planet. It passed beyond the orbit of the planets on February 23, 1990, making it the fourth man-made object to do so. The last meaningful data received was on November 24, 1995.  In 2002, its signal became too faint to detect.

Dawn arrives at Ceres 2015

Ceres as seen by Dawn

The spacecraft Dawn arrived at the minor planet Ceres March 6, 2015.  Launched September 27, 2007, Dawn made a flyby of Mars on its way to the asteroid belt, arriving at the minor planet Vesta July 6, 2011.  After a 14 month study, Dawn headed toward Ceres, the largest object between Mars and Jupiter.  Right away, Dawn started sending back stunning pictures of the minor planet, showing mysterious bright spots on the surface.

Dawn will continue to study Ceres until its fuel runs out later this year.  It will remain in a stable orbit around the minor planet.

Dawn, spacecraft to the asteroid belt, launched 2007

Dawn, NASA's spacecraft to visit dwarf planets Ceres and Vesta, formerly known as asteroids, in the asteroid belt was launched September 27, 2007.  After testing its boosters in orbit above Earth and then receiving a gravity boost from Mars, Dawn entered orbit above Vesta June 16, 2011.  After exploring Vesta for a little over a year, it headed toward Ceres.

Dawn reached Ceres in December 2014 and discovered 'light' spots on the surface.  NASA scientists concluded that salt-rich water might have welled up to the surface of the dwarf planet.

NASA originally planned to have Dawn visit a third body, Adeona, but decided the spacecraft would be best used studying Ceres.  Dawn's mission was extended for one year in June 2017 and it has enough fuel to last until the end of 2018.  At that time, NASA may put it into an orbit which will avoid impact with Ceres.  They do not want to contaminate any of the asteroids.

Pioneer 10 sends its last signal 2003

Fourteen years ago, January 23, 2003, Pioneer 10 sent its last signal received by Earth.  Launched March 3, 1972, Pioneer 10 was the first spacecraft to travel through the asteroid belt and the first to encounter Jupiter, up close and personal, reaching the gas giant December 3, 1973.

It continued broadcasting at a whopping rate of 256 bits/second, which degraded to 127 millibits/second.  When it was approximately 12 billion light-years (80 astronomical units) from Earth, its power fell below the level where it could send signals strong enough to be received.  Now it is estimated to be 116 AU from Earth.

Ceres (asteroid/dwarf planet) discovered 1801

January 1, 1801, Italian astronomer Guiseppe Piazzi of Palermo discovered what he thought was a comet, but after observing it 24 more times, he realized it was an asteroid, reclassified as a dwarf planet in 2006.  He named it Ceres, the Roman goddess of the Harvest.  It is the largest object in the asteroid belt but only 4% of our moon's mass.

NASA sent the spacecraft Dawn which reached Ceres in 2015.  It is the first time Ceres has been observed up close.  Dawn is still sending data on the dwarf planet.

Galileo spacecraft discovers asteroid Ida's moon Dactyl 1993

Dactyl 

Asteroid Ida and her moon Dactyl

On August 28, 1993, Galileo spacecraft snapped this photo of the asteroid Ida and captured an image that helped NASA scientists discover her moon, Dactyl. The picture was taken about 14 minutes before Galileo made its closest approach to Ida on its way to Jupiter.

Ida was discovered by Johann Palisa in September 1884.  Dactyl, named for the creatures that inhabited Mount Ida in Greek mythology, is about 90 km from Ida.  It measures about 1.6km x 1.4km x 1.2km.

Beautiful features are found on Ceres

Dawn, the space probe launched by NASA in September 2007, has achieved orbit over the once-asteroid, now-dwarf planet Ceres.  Employing a unique ion propulsion drive, Dawn was able to stop by Vesta for a year-long study before resuming her journey to Ceres, instead of mere fly-by’s like New Horizons had to do with Pluto.  Since Dawn’s arrival in March 2015, she has been sending back beautiful images, revealing mysterious features.

 

Among the most captivating photos show bright spots on the surface of Ceres.  Located at the bottom of the Occator crater, the spots seem to be sublimating material, a substance that transforms from a solid state to gas without passing through the liquid phase.  This process appears to be creating some sort of localized atmosphere inside the crater.

 

Another feature creating a stir is the ‘Lonely Mountain’, a solitary mound over 21,000 feet high.  What makes it so stunning is the strange but beautiful bright streaks on its sides.

Ceres is the final stop for Dawn and the probe will remain in orbit at about 230 miles above the surface.  Here she will begin to send even higher-resolution images of the dwarf planet.