Orion Nebula, Trumpler 14, Venus

Observatory / Course Archives / ASTR 110 Fall 2019 / Toma

Orion Nebula

Messier 42, popularly referred to as the Orion Nebula, is an emission/reflection nebula located in the constellation Orion, specifically in the south of the Hunter's belt in “the sword”. A nebula is a cosmic cloud of gas and dust floating in space. They contain the elements from which stars and solar systems are formed; think of them as nurseries for stars. Emission nebulae such as the Orion Nebula tend to glow red; this is due to the radiation emitted by the abundant hydrogen atoms energized by their stars amidst their high temperatures.

At a distance of 1344 light years to 1500 light years, Messier 42 is the closest massive star forming region to Earth. The nebula is believed to contain more than 1,000 young stars, and about 700 stars that are still in various phases of formation, possibly the youngest protostars ever found. Because it is relatively close and bright, it can be seen with the naked eye, and is easily seen through a telescope or binoculars.Located inside the nebula is the well-known young open star cluster, the Trapezium Cluster. M42 is part of a much larger nebulous region known as the Orion Molecular Cloud Complex, which stretches across the Orion constellation. This greater nebulous region also includes other celestial objects such as Barnard's Loop, the Flame Nebula, the Horsehead Nebula, Messier 43, and Messier 78. Astronomers have learned a lot about the formation of stars and planetary systems by studying this nebula, including the photo-ionizing the high mass stars in its clouds.

Trumpler 14

Trumpler 14 is an open cluster of about 2000 very bright young white-blue stars within the Carina Nebula. The cluster stretches across a distance of about 40 light years and is approximately 8,980 light-years away from Earth. It is one of the largest gatherings of hot, massive bright stars in the Milky Way galaxy, home to some of the most luminous stars. In fact, it is so bright it is often referred to as the "Dazzling Diamonds". Its stars vary in size from less than one tenth to several times the mass of the Sun in multiples of ten. The most prominent star in Trumpler 14 is the supergiant HD 93129Aa; one of the brightest hottest stars in our galaxy.

However, despite being so young, the stars form at such a fast rate and quickly use up their vast supplies of hydrogen that it seems in a few million years,the stars will reach the end of their lifespans and explode as supernovae. Interestingly though, the same high speed formation that shortens the life spans of the stars in this cluster also indirectly helps to kickstart the formation of other young stars. Strong stellar winds swell and travel out of the high speed particles thrown off the surface of the Trumpler 14 stars. These winds collide with other material resulting in shock waves that travel heat up the gas to extreme temperatures. These strong stellar winds carve out gaps in nearby clouds of gas and dust, and start the formation of new stars within the interstellar material.

Venus

Venus is the second planet from the sun in our solar system and the most proximate to earth. It's a terrestrial planet, usually considered the twin or sister planet of Earth due to similarity in size, mass, density, composition, proximity to the sun, and gravity. Venus appears as one of the brightest objects in our sky; actually the brightest object seen in after the Sun and Moon. It's also the hottest planet in our solar system, even described as hellish, though not the closest to the sun, with a temperature of 735 kelvin, or 461° C. It's extreme temperatures come from the runaway greenhouse effect it experiences: It's thick atmosphere (93 times thicker than earth's) made of primarily carbon dioxide traps the infrared heat from absorbed sunlight, thus warming up the planet. Venus orbits at about 0.7 AU from the sun, completing its journey around the sun in 225 earth days. It is however, unusual in its orbit because it rotates from east to west, the opposite direction from which all other planets rotate (except Uranus).

The clouds on Venus serves as its distinguishing characteristic. The completely opaque clouds block Venus's surface from sight, reflecting about 75% of the sunlight receive.The clouds are sulfuric, in nature, consisting of sulfur dioxide and sulfuric acid. The sulfuric acid is rained down from the clouds, but due to the extreme temperature, evaporates before reaching the ground and so returns into the clouds once again. In addition, lightning has also been detected by the Venus spacecraft in what might be a similar process to Earth's, yet again another shared characteristic between both planets.