Astronomy Pictures

Observatory / Course Archives / ASTR 110 Fall 2019 / DeJong

Flame Nebula

Nebular clouds are made up of hydrogen and helium gas found in space. It is in these clouds that stars are formed from the gases in the area. Most of the time there is enough gas present in a cloud like this to create thousands of stars, however sometimes nebula are the result of dead stars. The Flame Nebula is located 14,000 lightyears away from earth. It is found in the costellation Orion and was discovered in the late 18th century by William Herschel. Most of the shine emitted from the flame nebula is due to the Alnitak star; the bright blue star in the middle of the nebula. When wind and radiation hit this star, electrons are removed and put into the nebula where they ionize and produce light.

The Flame nebula is an emission nebula. Emission nebulas are made of ionized gas which happens when an interstellar gas cloud containing mostly neutral hydrogen becomes ionized by the presence of O and B type stars. When these hot stars give off high energy ultraviolet photons, the neutral hydrogen atoms break apart into nuclei and electrons. The hydrogen then refigures the atoms into an neutral yet excited allowing the atoms to return to their lowest energy and emitting wavelengths that can be seen by the human eye without any assistance.

Tres-2b

The planet Tres-2b is an exoplanet orbiting a star about 750 light years away from us in the constellation of Draco. It is a Jupiter sized gas giant discovered in 2006 by the Trans-Atlantic Exoplanet Survey. Though it was discovered in 2006, it did not become of interest until the Kepler space work in 2011. The Kepler spacecraft specifically looked for exoplanets using light sensors called photometers. It looks for exoplanets by watching out for dimming stars which could be the presence of a transiting planet. David Kipping, a professor at Columbia University, along with another colleague where able to identify the physical characteristics of the planet by taking a phase curve of the planet. A phase curve, as he explains is the total brightness of a star plus the small amount of a planet over time during it full orbit. It is done to determine the total reflection of the planet.

David Kipping nicknamed the planet “The Darkest World,” because of the amount of light absorbs. Tres-2b takes in about 99.9% of the light that hits it making it less reflective than coal. However, because the planet has a an orbital period of 2.47 days, it has a slight thermal glow because of its proximity to the sun. It is estimated that the temperature on the surface of this planet is about 1800 degrees Fahrenheit. It is also most likely that there is no clouds surrounding the planet and the atmosphere is made up of either gaseous sodium or potassium as they both tend to absorb a lot of light in gaseous states. Other than the hypothesized makeup of the atmosphere of the planet, scientists are unsure of what makes it so dark.

Pleiades Star Cluster

The Pleiades is a cluster of stars that appears in the constellation Taurus. It contains hundreds of stars with only some able to be seen with an unaided eye. This group of stars is relatively close to the earth in distance and it has been theorized that they all share a common origin and a common gravitational bond. The Pleiades is an open star cluster so singular stars belonging to it can be seen through a telescope and this is a result of their physical distance to earth. The middle part of the Pleiades cluster is a spherical shape that spans about 4.5 lightyears while outer part of the of the cluster is more of an elliptical shape with an eccentricity of .17 with the tidal radius of the whole cluster being about 52 lightyears.

The Pleiades can be seen from pretty much every spot on the globe while being very prevalent in the northern hemisphere during the winter months. They are considered sister stars because they are believed to have been born of the same dust. There is some evidence of terrestrial planets around on of the stars which is important because the rockiness of the planet could potentially mean that other life forms can be found on it. The star that it orbits, HD 23514, is important as well because its characteristics categorize it as a younger sun. This discovering will be important as we begin to search more for life sustaining planets. The faint blue nebula that is seen in the picture above suggests that overall the cluster has form relatively recently because the dust has not been blown away by the ultraviolet radiation coming from the hot stars.