Snippets of Our Incredible Universe

Observatory / Course Archives / ASTR 110 Fall 2019 / German

Kepler-16 b

An exoplanet is a planet that orbits a star other than the sun. They have been discovered to be many different sizes and temperatures; they can be as big gas giants or as small as Mars, hot enough to boil metal and so cold that everything is frozen. Today we currently have 3,700 confirmed exoplanets and the number keeps rising. Astronomers can detect these exoplanets primarily using two different methods: the radial velocity method and the transit method.

The Kepler 16b is a circumbinary exoplanet and it was the first exoplanet discovered that orbits two stars. It was discovered in 2011 using the transit method. When the astronomers noticed that one of the stars dimmed, they didn't think too much of it because it was already known to be a binary star system. However, after further observations, they noticed that the star dimmed even when they weren't transiting one another; thus the Kepler 16b was discovered. Today, it is commonly referred to as the "Star Wars tatooine" since, like the Star Wars planet, the sun sets twice. The Kepler 16b has an orbital period of about 229 days and is approximately 200 light years away from earth. One interesting fact about the Kepler 16b is that it orbits only 9% further than the minimum critical distance needed for orbital stability. This causes astronomers to infer that it did not form in its current orbit but over time, gravity forced it to move closer to its stars.

Messier 64

A spiral galaxy is one of the two types of galaxies. They are typically younger than elliptical galaxies and often contain nebulae which means that star formation often occurs in spiral galaxies. Spiral galaxies can be either barred or unbarred, barred galaxies have a bright linear feature that straddles the nucleus while unbarred galaxies have arms that emanate from the nucleus which is where star formation occurs.

This picture of the Messier 64 was taken with four different color filters that isolated blue and near infrared light. The Messier 64 galaxy can be found in Coma Berenices constellation. Also known as the Black-Eye Galaxy it got its name because it is a relatively bright galaxy that can be seen with even a small telescope. It gets its name, the Black-Eye Galaxy, because as you can see in the picture, it contains a dark dust lane that when you see it through a small 4-in telescope, you cannot see its nucleus. It is thought to have been formed from the collision of two galaxies thus causing its stars to rotate clockwise while the interstellar gas around it rotates counterclockwise. From this picture, we can tell that there is star formation or at least there was in the near past from the color of the stars. Most of the stars seen in the picture are blue which implies that they are younger, colder stars. If you were to see this image in ultraviolet, you would be able to see pink clouds of hydrogen surrounding the stars. Astronomers have found that it contains approximately 100 million stars however, they have yet to detect any supernovas.

Orion Nebula

Nebulae are giant clouds made up of gas and dust and it is often where star formation occurs. They lie in the space between stars known as the interstellar. Astronomers mainly see and study these through their telescopes, though there are some that are so bright that they can be seen with the naked eye.

This picture of Messier 42 was taken using 520 different Hubble exposures from multiple different wavelengths which created one of the sharpest pictures we've ever had of this nebula. The Messier 42 is more commonly known as the Orion Nebula. It has an apparent magnitude of 4 and can be found in the Orion constellation just below Orion's belt and it lies approximately 1,500 light years away. It is an emission spectrum and has a reddish-pinkish color because it is mainly composed of ionized hydrogen. Within the Orion Nebula there are 4 stars that give the nebula its shaped which are referred to as the trapezium. Scientists believe that these stars are relatively young as they still have their disks. An interesting fact about this particular nebula is that its emits supersonic "bullets" known as the Orion Bullets. They are massive "bullets" that shoot out at approximately 400 km per second.