Astronomy and Astrophysics: Two weeks in two minutes

Astronomy and Astrophysics: Two weeks in two minutes

A selection of interesting developments in astronomy and astrophysics from the past couple of weeks.

 

We get the best view of the dwarf planet Ceres yet:

Ceres-HST-Dawn

As NASA’s Dawn mission nears Ceres, each picture gives us tantalising amounts of detail on the mysteries of the dwarf planet. In 2011, Dawn gifted us with amazing images of the massive asteroid Vesta and since then has been using its revolutionary ion engine to place itself in orbit around Ceres.

In April it should be in a stable orbit of the planet, and NASA have planned to leave it in that orbit when its fuel runs out as a permanent landmark to our endeavour. The orbit has been carefully chosen so that it does not contaminate the planet due to the potential presence of water there.

In the mean time, we are seeing that the icy planet we originally thought to be smooth is in-fact far from it. It is littered with craters and other interesting geological features which makes us question our initial assumptions about its evolution. We just need to wait and see what discoveries are made in the next couple of months.

 

Earth sized planets forming near the beginning of the Universe:

Illustration of Kepler-444 and its five earth-like planets. Image courtesy: Tiago Campante/Peter Devine

Illustration of Kepler-444 and its five earth-like planets.
Image credit: Tiago Campante/Peter Devine

At 11.2 billion years old, the star Kepler-444 is no spring chicken. In fact it is almost as old as the Milky Way, which makes it even more incredible that such an old star has 5 planets with sizes varying from that of Mercury to Venus. To put things in perspective, our juvenile Sun is only 4.5 billion years old.

Findings such as these help scientists to rethink ideas surrounding planetary evolution, and its potential for the existence of other, ancient, life in the Galaxy. Asteroseismology was originally used to determine the age of the star and its planets, a technique which involved measuring oscillations of the star by sound waves within it.

Unfortunately, the planets have orbits of less than 10 days at a distance one fifth of the Earth’s orbital distance, so there’s certainly no water and no life.

Asteroids have moons:

Asteroid2004BL86 has a Moon

Asteroid ‘2004 BL86’ has a moon. Image credit: NASA

Asteroids are fascinating. They can tell us about the early life of the solar system and can have very interesting chemical makeups, but generally, they are in a chaotic area with other asteroids so don’t tend to buddy up. 2004 BL86 has though, and as it passed by Earth at a distance of 1.2 million kilometres (a very safe distance), it was radar mapped. The rotation rate was found and its surface was observed, but most interestingly, the asteroid (only 325m wide) has a 70m wide moon.

The asteroid will pass by us at the same distance in 2027 so hopefully these two will still be chilling out together in the open space.

 

Planet with a ring system larger than Saturn:

Artist’s conception of the extrasolar ring system circling the young giant planet or brown dwarf J1407b. The rings are shown eclipsing the young sun-like star J1407, as they would have appeared in early 2007. Image credit: Ron Miller

Artist’s conception of the extrasolar ring system circling the young giant planet or brown dwarf J1407b. The rings are shown eclipsing the young sun-like star J1407, as they would have appeared in early 2007. Image credit: Ron Miller

It tends to be the case that when you think of a ring system on a planet, your mind automatically jumps to the planet Saturn. Of course, it’s pretty close to us (relatively speaking) and now holds a legendary status as the galactic ring bearer. But here’s something even better: an exoplanet with rings 200 times larger than Saturn’s has been discovered. To put this in perspective, Saturn’s rings are 175,000 miles across (roughly the distance between the Earth and the Moon) and have a mass equivalent to earth. Hopefully, you can now start to imagine how large this ring world, named J1407b, really is.

The identification of the rings of J1407b were made when scientists identified that they were blocking out 95% of the light from its parent star, J1407 for several days. Additionally, a gap in these rings were found which could indicate the formation of a moon,  but hasn’t currently been observed yet. This sounds like a job for the E-ELT to me.

This discovery marks the first ring system discovered outside of our solar system, and thanks to its colossal size, we know that we’re looking at a relatively young planet with its moons still forming.

There is a petition to rename the planet as Planet Tolkien, as it is said to have the ‘Rings to Rule Them All’.

 

Black hole observed choking on a star  


Now, we all know how hungry black holes are, and in 2009, the ROTSE IIIb telescope was granted to a feast. The telescope caught an extremely bright flash of light 2.9billion light years away (6 times as bright as the Milky Way). At first, astronomers believed it could have been a number of things, such as a gamma ray burst or the merging of 2 neutron stars, but it is now believed to be a star being pulled in by a black hole.

The event was nicknamed ‘Dougie’, after the South Park character, and is known as a tidal disruption event, where the star will be stretched into a disk and may end up as a large elliptical orbit around the hole before it’s eventually consumed, all the while radiating intensely. No one likes being eaten, really.

 

 Fermi bubbles discovered in our galaxy:

Image courtesy: NASA

Fermi bubbles in the Milky Way. Image credit: NASA

Our Galaxy is not blowing bubbles, but what it does have is two huge radiation structures, extending thousands of light years above and below the plane of the Galaxy. What this indicates is that millions of years ago the supermassive black hole at the centre of our Milky Way was far more active than it is today and feasted on enormous amounts of gas and dust. Black holes eat weird things.

These bubbles are observed in other galaxies but it’s unclear if they’re formed by the same process. By further studying these phenomena we can learn more about dark matter and its location. Gamma rays are produced when dark matter particles interact, so we have a lot of dark matter in the centre of the Galaxy, but it still remains as mysterious as ever.

 

Sam McMaster

Feature Image Credit: NASA Ames/SETI Institute/JPL-Caltech

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