ECLIPSE NEWSLETTER The Eclipse Newsletter is dedicated to increasing the knowledge of Astronomy, Astrophysics, Cosmology and related subjects. VOLUMN III - NUMBER I JANUARY – FEBRUARY 2019 PLEASE SEND ALL PHOTOS, QUESTIONS AND REQUST FOR ARTICLES TO [email protected] Page | 1 CONTENTS: CONSTELLATION ORIAN WHAT ARE THE MESSIER OBJECTS? MESSIER OBJECT NUMBER 42 WHAT IS THE LIFECYCLE OF A STAR? PART 1. DARK MATTER MCAO PUBLIC NIGHTS AND FAMILY NIGHTS. HOW TO FIND CONSTELLATIONS HYPERLINKS IN BLUE DEFINITIONS IN RED ORION CONSTELLATION Around this time of year, I like to revisit the Orion Constellation. I have always thought of Orion as the Archer. He has drawn his bow. His arrow is pointing at Antares, the bright red heart of Scorpius, the scorpion. The archer is avenging Orion, who was slain by the scorpion's sting. Others view Orion as the Hunter. Page | 2 To others, Orion is viewed with a club and Lions head. As the old saying goes, it’s all in the eye of the beholder. Once you have chosen how you prefer to view Orion, we can move on to some interesting information. Orion is clearly visible in the night sky from November to February. Orion is in the southwestern sky if you are in the Northern Hemisphere. Alnilam, Mintaka and Alnitak, which form Orion’s belt, are the most prominent stars in the Orion constellation. Betelgeuse, the second brightest star in Orion, establishes the right shoulder of the hunter. Bellatrix serves as Orion's left shoulder. We can also find in the Orion Constellation, the Orion Nebula. Page | 3 The Orion Nebula — a formation of dust, hydrogen, helium and other ionized gases rather than a star — is the middle "star" not exactly, in Orion’s sword holder, which hangs off of Orion's Belt. The Horsehead Nebula is also nearby. Other stars in the constellation include Hatsya, which establishes the tip of Orion's sword that hangs off the belt, and Meissa, which forms Orion's head. Saiph serves as Orion's right knee. Rigel, Orion’s brightest star, forms the hunter's left knee. WHAT ARE THE MESSIER OBJECTS? The Messier objects are a set of over 100 astronomical objects first listed by French astronomer Charles Messier in 1771.[1] Messier was a comet hunter, and was frustrated by objects which resembled but were not comets, so he compiled a list of them,[2] in collaboration with his assistant Pierre Méchain, to avoid wasting time on them. The number of objects in the lists he published reached 103, but a few more thought to have been observed by Messier have been added by other astronomers over the years. For a list of Messier objects: https://en.wikipedia.org/wiki/List of Messier objects THE ORIAN NEBULA MESSIER OBJECT 42. Page | 4 The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features. The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust. The nebula is visible with the naked eye even from areas affected by some light pollution. It is seen as the middle "star" in the "sword" of Orion, which are the three stars located south of Orion's Belt. The star appears fuzzy to sharp-eyed observers, and the nebulosity is obvious through binoculars or a small telescope. The peak surface brightness of the central region is about 17 Mag/arcsec2 ( Mag/arcec (is a value used to define surface brightness)) (about 14 milliunits) (a unit of measurement) and the outer bluish glow has a peak surface brightness of 21.3 Mag/arcsec2 (about 0.27 milliunits). (In the photo shown here the brightness, or luminance, is enhanced by a large factor.) The Orion Nebula contains a very young open cluster, known as the Trapezium due to the asterism of its primary four stars. Two of these can be resolved into their component binary systems on nights with good seeing, giving a total of six stars. The stars of the Trapezium, along with many other stars, are still in their early years. The Trapezium is a component of the much larger Orion Nebula Cluster, an association of about 2,800 stars within a diameter of 20 light years. Two million years ago this cluster may have been the home of the runaway stars AE Aurigae, 53 Arietis, and Mu Columbae, which are currently moving away from the nebula at speeds greater than 100 km/s. Page | 5 Orion Nebula Trapezium is in the center of the green area. WHAT IS THE LIFECYCLE OF A STAR? Our Star, the Sun, is considered by most to be a 3rd generation Star. Two other generations of Stars preceded it. They are known as 1st and 2nd generation Stars. Page | 6 The universe is constantly evolving. Even today, clouds of dust and gas swirling among the vast reaches of space remain capable of giving birth to new stars just as they did billions of years ago. Obviously, not all stars came into existence at the same time. At 4.3 billion years old, the star the Earth orbits and that humans call the sun is among the younger stars known which are referred to as 3rd generation stars. However, there were two generations of stars that came before the 3rd generation. More on that later. Like so many things in the universe, stars begin very small -- mere particles in vast clouds of dust and gas. Far from active stars, these nebulae remain cold and monotonous for ages. Then everything stirs up when a newcomer speeds through. This disturbance might take the form of a streaking comet or the shockwave from a distant supernova. As the resulting force moves though the cloud, particles collide and begin to form clumps. Individually, a clump attains more mass and therefore a stronger gravitational pull, attracting even more particles from the surrounding cloud. Refer back to the picture above. As you can see, the process starts with a nebula which turns into a dust cloud then a Globule and then a Protostar. One of two things will happen to the Protostar. Become a full-blown star or a Brown Dwarf. More later. For now, let’s consider the 1st generation of stars. The best evidence yet for the very first generation of stars, ones made only from ingredients provided directly by the big bang they being made from essentially only hydrogen and helium. These 1st generation stars concentrated in the disks of spiral galaxies. Second generation stars tend to be found in globular clusters (a large compact spherical star cluster) and the nucleus of a galaxy. They tend to last longer therefore being older than the 1st generation of star we can still observe and less luminous and cooler than 1st generation stars which are predicted to be enormous in size, live fast and die young. Until recently, many astronomers had thought they would never be able to see such stars, because they would have all burned and died in the universe’s early history therefore too far for us to see. But using new instruments on the world’s top telescopes, a group of astronomers found a uniquely bright galaxy that seems to bear all the hallmarks of containing 1st generation stars. The space between stars, termed the interstellar medium, is filled with gases and traces of molecular elements. Most abundant in the interstellar medium is hydrogen gas, followed by helium. Certain pockets of space are so cold and lacking in energy that gravity can pull these gases together with particles of dust, eventually giving rise to stars. For this reason, scientists believe that the first stars were composed primarily of these abundant gases, hydrogen and helium. 2nd generation stars tend to be older, less luminous and cooler than 3rd generation stars. Stars may be classified by their heavy element abundance, which correlates with their age and the type of galaxy in which they are found. 3rd generation stars which includes the sun tend to be luminous, hot and young, concentrated in the disks of spiral galaxies. They are particularly found in the spiral arms which is where we find our star. Back to the life cycle. How does a nebula change into a protostar? A nebula is made of clouds of gas and dust. There is hydrogen gas, of course, and hydrogen atoms. Due to gravity, hydrogen gas tends to clumped together, and the hydrogen atoms Page | 7 will start to spin and pulls up more hydrogen atoms that will cause collision. This collision of the hydrogen atoms causes the hydrogen gas to heat up. When the temperature reach 15,000,000 C , (27,000.000 F) nuclear fusion starts. A protostar is then formed. Let’s go back to the Life Cycle of a Star picture above and start with a Nebula. The most common Nebula∘ for us is the Orion Nebula. The above shows the location of the Orion Nebula. The best-known image from the Orion Nebula is the Horse Head but is not all inclusive of this Nebula. The Horsehead Nebula is a dark nebula in the constellation Orion. The nebula is located just to the south of the star Alnitak, which is farthest east on Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex. Let’s review a bit. Stars begin as a particles in clouds of dust and gas called Nebula. A Nebula will remain cold and basically inactive for ages. Then, the Nebula begins to stir up due to a disturbance.