Semester APOD Project

Observatory / Course Archives / ASTR 110 Fall 2019 / Norman

Rosette Nebula

The Rosette nebula is a stellar nursery located about 5,000 light-years away from Earth in the Monoceros constellation. Althought we were only able to perceive about 36 young stars in one section of the nebulea, named NGC 2237, we are now able to detect 160 new stars using the Chandra X-Ray observatory. While this nebula is constantly forming new stars, the older, hotter stars give off intense winds and radiation which strip the younger cooler stars of their planet-forming materials. The radiation and winds from the hot stars have moved aroud the dust in different areas of the nebula, revealing new sights. One of these sights is a large central hole, which it is too faint to see with a naked eye, a small telescope may allow to a good view.

This image of the Rosette Nebula exhibits a few of the amazing colors that can be detected from this nebula. The reddish hue commonly seen in images of the Rosette Nebula is where the nebula gets its name.

Hoag's Object

Hoag's object is a unique example of what is now referred to as a ring galaxy. It exhibits an interesting structure comparatively to other galaxies, the outside ring is comprised of mostly young stars giving off blue light, while the center gives off a yellowish light from the older, redder stars. The area in between appears to be almost completely empty. How this structure was formed and has remained is not yet known, although other structures have been discovered. Hoag's Object spans about 100,000 light years across from one side of the ring to the other,

In this Hubble Space Telescope image, we see Hoag's object straight on, the blue ring almost perfectly centered around the yellow glowing center bulge. Inside the ring, we see a second ring galaxy positioned far behind Hoag's object. This unique occurance of two ring galaxies being positioned so near each other has lead these objects and image to be referred to as "a Ring withing a Ring."

Gliese 436b

Orbiting its host M-dwarf type star Gliese 436, Gliese 436b is one of the smallest dwarf planets scientists have discovered. With a mass and radius similar to Neptune, Gliese 436b is unique for it's incredibly small orbital radius and period. It's orbit period lasts only 2.64 days and its radius is approximately 2.5 million miles, almost 14 times closer than Mercury, the closest planet ino our solar system, which orbits at almost 36 million miles away from the Sun. Adopting the nickname "the Warm Neptune," Gliese 436b is an anomaly based on our current understanding of the relationship between an exoplanet's size, composition, and orbital radius. The exoplanet's close distance to its star means that a gaseous tail has been observed as the atmosphere is being stripped away by the host star's solar winds. Additionally, it has been found that gliese 436b is orbiting it's host star almost perpendicularly to the star's stellar equator. This high eccentricity suggest that there may be another yet-to-be detected exoplanet. This characteristic may also be evidence for the anomaly that has caused such a large, gaseous planet to survive so close to its host star. however other studies have found evidenc to contradict this claim.

This image is an artist's depiction of what a view from beyond Gliese 436b may look like. Since this exoplanet is so close to it's host star, we don't have to ability to properly photograph the exoplanet. The star's light outshines whatever image of the planet we may attempt to take. Without sending a probe far out into space to specifically photograph this exoplanet, we may never know the exact appearance of Gliese 436b.