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Observatory / Course Archives / ASTR 110 Fall 2019 / Brink

Kepler 22-b

An exoplanet is a planet that orbits a star other than the sun. It is thought that the number of exoplanets in the Milky Way alone, is potentially up in the trillions. There are two main methods that are used to detect exoplanets: the radial velocity technique, and the transit method. The radial velocity technique is when an exoplanet is detected by observing a star's wobble through the Doppler effect, due to the tug of the planet, and the transit method is when an exoplanet passes in front of its star, causing there to be a slight decrease in that star's brightness. The image shown is of the exoplanet Kepler 22b. Its host star is located around 600 light years away, and is very similar to our sun, only slightly smaller and cooler.

This artist's rendition of Kepler 22b showcases what the exoplanet might look like if covered in large ocean, which some astronomers theorize is possible and even dub it the "water world." This is due to the fact that it is located in the star's Habitable zone, the region where water is able to exist as a liquid on a planet's surface. Discovered by NASA's Kepler mission in February of 2011, Kepler 22b is the first habitable zone planet to be confirmed by them, among 54 others. Its diameter is about 2.4 times that of earth, with an average surface temperature of 72 degrees Fahrenheit. It has an orbital period of 290 days, and as far as scientists know, does not have any moons.

Ghost Nebula

Pictured here is IC 63 or, as it is more commonly known as, the Ghost Nebula. Nebulae are massive clouds of gas and dust in space where star and planetary formation happens. Most nebulae are large in size, sometimes reaching up to hundreds of light years across. This particular nebula is located about 550 light years away and is located in the Cassiopeia constellation. It was first photographed by Hubble in August 2016.

The Ghost Nebula seems to contain long, flowing veils and, hence the name, appears as a ghostly apparition in space. This form is actually due to the fact that this nebula is being bombarded by UV radiation from nearby star Gamma Cassiopeiae, causing it to slowing dissipate over time. This radiation also blasts the hydrogen atoms, raising the energy levels of the electrons and eventually releasing this energy as hydrogen-alpha radiation, which gives it that pinkish glow and also why it is classified as an emission nebula. IC 63 is also classified as a reflection nebula, as the dust reflects the light of previously mentioned star, Gamma Cassiopeiae, which is the source of the bluer colors observed in the image.

Sunflower Galaxy

Galaxies are large collections of gas, dust, and stars and their solar systems. Many of them contain a supermassive black hole in their centers. The number of galaxies in the universe is theorized to possibly be over 100 billion, each containing (depending on the size) upwards of billions, possibly even trillions of stars. There are three general types of galaxies: spiral galaxies, which are characterized as having a disk shape with spiral arms and a bulge in the middle, elliptical galaxies, which are generally round in shape, and irregular galaxies, which seem to lack any distinct form.

This specific galaxy is called Messier 63 or, the Sunflower Galaxy, as it takes on the appearance of the center of a sunflower. This galaxy falls into a special subset of spiral galaxies called a flocculent spiral. These are characterized as having the form of a spiral galaxy, but without well-defined arms. Like almost every other galaxy, M63 is shrouded in a halo of dark matter, which actually makes up 95% of the galaxy's mass. It was found that if it wasn't for this dark matter, the galaxy would rip itself apart due to how fast the outer edges are rotating. All of the bright, blue specks that light up the arms of the disk are young, blue giant stars which is a sign of recent and ongoing star formation. The Sunflower Galaxy is located about 37 million light years away from earth and is part of the group of galaxies called M51.