Hunting for Ceres in the Pipe Nebula

Ceres is the largest asteroid in the solar system, and is usually bright enough to be visible with telescopes and even binoculars (at around a magnitude of 7). However, unlike the brighter planets, it is not so bright to be able to be distinguishable from the stars that may surround it. Normally to do that would require taking multiple exposures of the field to see which one of the dot moves¹, or at the very least, looking at charts giving its position in relation to other stars. However in the month of July, due to its special position, identifying became a lot easier.

In July, Ceres passed in front of Barnard 78 (or the Pipe Nebula), a nebula in the Ophiuchus constellation made up of dark dust and gas. This opportune position allows the nebula to block out background stars which may be confused for the asteroid. Since Ceres is in our solar system, it isn't blocked out, allowing it to be made out easily.

When I observed Ceres on July 20 with my 15x70 binoculars, it took me just a few minutes to identify which dot was Ceres. If you have binoculars or a telescope, definitely try and go outside to see this asteroid. This special position won't last for long!

When hunting for the asteroid, using a chart from a computer is immensely helpful. I used charts from the iPhone/iPad app SkyVoyager and the July issue of Astronomy magazine.

Footnotes

1: Since the Earth rotates, stars rise in the east, move across the sky, and set in the west, just like the Sun. Asteroids (and also planets) also move in their orbits, so in addition to rising and setting, they move across the sky not following the other stars [this is why the name planet comes from the Greek work “wanderer”]. When taking multiple exposures and aligning the stars in the pictures, the one that moves is the asteroid, since it is not following the movement of the stars.

Rosetta's Closeup with Asteroid Lutetia

Asteroid Lutetia, captured by Rosetta
Image: ESA

ESA’s Rosetta mission successfully completed a flyby of asteroid Lutetia on July 10, capturing spectacular images of a remnant from the solar system’s creation. The spacecraft came as close as 3162 km, at a velocity of 15 km/s. At that velocity, the flyby did not last long (about a minute), but the craft was prepared with a variety of sensors to capture data before, during, and after the short flyby. Rosetta hunted for evidence of the presence of an atmosphere and magnetic effects, while studying the composition and density of the rocky body. The spacecraft even tried to capture and analyze grains of dust from the asteroid that may have been kicked into space around the asteroid. The results from these studies will be revealed at a later time.

Probably the most breathtaking of the rich information the Rosetta spacecraft captured from its flyby are the magnificent images of the rocky body. The craters and the surface of the asteroid are revealed in a stunning amount of detail, never before available to us. The images were especially breathtaking for me since I worked on researching asteroids for my high school senior project. Looking at just a tiny dot moving across a computer screen, I could never help but wonder what that tiny dot really is. What does it actually look like and what is it made of? Now looking at any asteroid, at what on Earth would appear as just a small dot indistinguishable from the hundreds of stars on an image, take on a definite and unique shape never ceases to blow me away.

Asteroid Lutetia with Saturn
Image: ESA

My favorite image from Rosetta is the image of asteroid Lutetia captured alongside Saturn. It nicely frames one of the largest bodies in the solar system with one of the smallest.

The Rosetta mission itself was launched in 2004, and is headed towards comet 67P/Churyumov-Gerasimenko, with that encounter scheduled for 2014. It will orbit the comet and deploy a lander, studying its composition which will help us eventually understand more about comets and the early solar system. In fact, Rosetta’s name originates from that of the Rosetta Stone, since it is designed to unlock secrets about the solar system before the existence of planets, much like how the Rosetta Stone unlocked secrets about Egyptian hieroglyphics. Asteroid Lutetia is the second asteroid that the spacecraft has flown by on its way to the comet.

Additional images of Lutetia captured by Rosetta are included below. (Images: ESA)

 

 

P.S. This is my blog’s 100th post. Wow.

Hayabusa's Rocky Journey Ends with a Spectacular Return

Image of asteroid Itokawa taken by the Hayabusa probe.
JAXA

A Japanese space capsule, released by the Hayabusa asteroid probe, returned successfully to Earth today, with a spectacular, fiery show. The return marks the end of the seven year Hayabusa mission. The mission is returning from a nearby asteroid, named Itokawa, with a capsule perhaps filled with material collected from the asteroid itself. [Video of reentry and full description of mission below the fold.]