APOD Project

Observatory / Course Archives / ASTR 110 Fall 2019 / Herman

Eagle Nebula (Messier-16)

Messier 16, also known as the Eagle Nebula, is a young, star-forming open cluster located in the Serpens constellation. Discovered in 1745 by the Swiss astronomer Jean-Philippe Loys de Chéseaux, Messier 16 is located 7,000 light-years from Earth.

First imaged in 1995 using Hubble's Wide-field Planetary Camera 2, Messier 16 is perhaps most well-known for its towers of cosmic dust and gas, composed of Evaporating Gaseous Globules (EGGs), known as the "Pillars of Creation." The namesake of these towers references the active [star formation] taking place. The tallest of these pillars, the Stellar Spire, is 9.5 light years in length. The presence of [blue light] found within the nebula is indicative of the presence of the element oxygen, the red light indicates the presence of sulfur, and the green light shows the presence of nitrogen and hydrogen. A massive structure, Messier 16 encompasses an area of about 70x55 light years. The pillars themselves stretch between 4-5 light years. Messier 16 is a diffuse emission nebula located in the Sagittarius Arm of the Milky Way. Only being 1-2 million years, it contains approximately 8100 stars, the brightest of which is binary star with a luminosity over one million times greater than that of the sun.

Kepler 16-b

Kepler 16b is an extrasolar planet with a circumbinary orbit and was discovered by NASA's Kepler Mission in 2011. The planet itself is a gas giant, is cold, and composed half of rock and half gas. Discovered by Laurence Doyle, it he mass of the planet, now estimated to be 0.333 Jupiter masses, was easily determined as it transits both stars.

Though the proximity of Kepler-16b's orbit to its host stars was originally considered to be unusual, astronomers used to believe the planet was captured. However, it is now believed that the planet formed within the same circumbinary disk, as the orbits of the stars and the planet align within a degree. Kepler-16b has an orbital period of 229 days.

Messier 64

Messier 64 possesses the lighthearted nicknames "The Black Eye Galaxy" and "The Evil Eye". Provided by NASA and the Hubble Heritage Team, the photo indicates a Galaxy with a noticeable dark band of dust in front of the galactic nucleus. According to the team, this is the result of a collision between galaxies. Located in the Virgo supercluster and the Coma Berenices constellation., the 70,000 light year-across galaxy is home to approximately 100 billion stars. Messier 64 is a spiral galaxy classified as a Type II Seyfert Galaxy which is one of the largest groups of active galaxies.

The galaxy contains some odd characteristics, such as its internal motion, wherein the gas of the outer region rotates in the opposite direction from that of the inner region. Another place of confusion lies within the distances. Despite containing cepheid variable stars, as well as O type stars, astronomers have failed to reach a consensus on how far away the galaxy actually is.