Observations of a Disturbed Circumstellar Disk

Planets are thought to form in the circumstellar disks around young stars. Astronomers have simulated this with computer model, and have been able to replicate (to a pretty good extent) the formation of our solar system via the circumstellar disk around our sun when it was very young. Planet formation is evident around nearby young stars as well. The caveat is that we can not directly see the planet forming inside the disk. Instead, astronomers use infrared and radio data to infer the a gap in the disk, probably due to the formation of a planet. Recently, astronomers were able to catch a rare glimpse or what appear to be a circumstellar disk around a star that's been distorted due to the presence of a planet.

 

Now we can't see the planet directly, but the fact that the disk has a spiral shape and not a circular shape suggests that a planet has been gravitationally disturbing the disk material. The image was taken with the Subaru telescope, an optical and infrared 8.2m scope in Mauna Kea, HI. The light from the star has been intentionally blocked out in the image, so that we can see the disk glowing in infrared. The disk is bright in the infrared because it is colder than the star it surrounds. How are we able to see such a disk? It's a combination of the fact that the telescope is very large, it uses very high tech adaptive optics to remove atmospheric affects, and the star is relatively close to us (~450 ly away). Astronomers are not certain that these arms are due to planets, but modeling shows that planets do have the capability of causing such structure. More modeling observations will need to be done to confirm these ideas.

Image credit: NASA's Goddard Space Flight Center/NCSA

Our Solar System

After some recent teaching experiences and discussions, I've come to realize that many adults have forgotten the basics about our solar system. So today ADYK presents a Solar System "refresher" to help you recall those astronomy facts you learned back in elementary school.

 

Above is a collection of real telescope images of the planets in our solar system (NOT to scale!). This is what the planets look like when you use very high power telescopes or planet orbiting satellites to observe them.

Our solar system contains 8 planets (Pluto doesn't count anymore),  one star (the Sun) and two large asteroid belts. Mercury, Venus, Earth and Mars and the four closest planets to the sun and are often called the terrestrial or rocky planets. They are basically giant chunks of rock in a roughly spherical shape. Mercury is made mostly of metals and is heavily cratered like the moon. Venus has a thick carbon dioxide atmosphere, and is essentially the poster child for what would happen if global warming got out of hand on earth. Earth is our home and is made of 70% salt water and has a rich Nitrogen atmosphere. Mars is the red planet where all the aliens live, supposedly. (*wink wink*). Beyond Mars sits the first asteroid belt, filled with oddly shaped rocks the size of people to the size of cities. Jupiter, Saturn, Uranus and Neptune sit beyond the asteroid belt and are often called the gaseous or Jovian planets. Jupiter is the largest planet, about 10x the size of Earth, and has that big red spot. Saturn is the one with the prominent ring structure, though all Jovian planets have a slight ring structure around them. Uranus and Neptune are the blue planets, and are about 4x the size of Earth. Uranus is turned on it's side, meaning that its spin axis is tilted 90 degrees from being straight "up and down". Past the Jovian planets is the Kuiper belt, a giant ring of asteroids which defines the edge of the solar system. Pluto, it's moons, and over 70,000 similar objects orbit in this ring. Most everything there is small, cold, and icy.

There you go, elementary school astronomy class in one paragraph!

Ring Around The.... Planets?

Open a new tab in your internet browser (yes, right now). Go to Google and pull up an image of Saturn (I don't care that you know what it looks like, just do it). Remember that picture, and look up a picture of Jupiter, Uranus and Neptune as well. Now if I start singing the song "One of these things is not like the other…" what would your answer be?...... The answer I was going for was Saturn! What's so different about Saturn? Well as you saw from the picture, Saturn has a beautiful ring structure and the other planets don’t….. Wrong! Believe it or not, all of the gas giant planets have rings! (Now if you didn't actually go to Google before, I bet you are now just to see if you can find a wiki page on ringed planets to see if I'm right.) 

 

Saturn's ring structure is very bright and prominent because it is thick and made mostly of ice which reflects light. The rings around Jupiter, Uranus, and Neptune are much thinner and are mostly made of rocks. Pictures of each planets rings are shown above. There's a big black spot over Neptune because Neptune is so bright compared to its rings that the planet's light needed to be blocked out so the rings were visible . Now when someone refers to Saturn as the ringed planet you can say "actually, all the gas giants have rings… but I know which one you mean."

Image credits: NASA/Voyager/J. Rayner/NSFCAM/IRTF