APOD 3.6

NGC1999: South of Orion (24 February 2011)

This is a picture south of the Orion Nebula. This reflection nebula is known as NGC 1999. 1,500 light-years away is the star V380 Orionis that illuminates this nebula. In the center of the bluish colored nebula, you can see a dark shaped sideways T. It spans over 10 light years. This empty space was discovered by Herschel. At first, he thought it was black because it was a dense cloud of dust and gas that was blocking light from coming through. When he looked at it with his infrared telescope, which are supposed to be able to see through these clouds, it was still black. This surprised him. It was determined that it was actually not a dense pocket of gas and it seemed like something had actually blown a hole right through the cloud.

This is the first time astronomers had seen something like this. They think the cause of the hole was from narrow jets of gas from some of the young stars in the region. Those jets of gas must have punctured the sheet of dust and gas and nearby a mature star with powerful radiation may have also helped create this whole. The jets and outflows created by the nebula's young stars also create shock waves. These shocks appear bright red in this picture. These stellar jets and outflows come through at speeds of hundreds of km/sec. This was really interesting because relating what we have learned in class, it shows the nature of newborn stars and how powerful they are. Something like this sound pretty normal, but it turns out it was actually a big deal when astronomers discovered this hole in the nebula. It really shows how astronomers and scientists try to learn from every single thing they see.

Biography of Simon Newcomb

Simon Newcomb was born in Wallace, Nova Scotia, Canada on March 12, 1835. His father, John Burton Newcomb, was a schoolteacher, and his mother Emily Prince, was the daughter of a New Brunswick magistrate. As a child, he lived in various villages in Nova Scotia and Prince Edward Island. When Newcomb was 16, he was apprenticed to Dr. Foshay. Newcomb was supposed to learn medical botany and in return he would serve as a general assistant for five year. Unfortunately, Dr. Foshay was a cheat and Newcomb wasted two years serving him. He ran away and eventually journeyed to Salem, Massachusetts where he met his father as they continued on their way to Maryland.

            There in Maryland, Newcomb was able to get a teaching post at a country school. In his free time, he taught studied Newton’s Principia and taught himself mathematics. In 1856, he became a private tutor near Washington which allowed him to frequently visit the capital. There, he visited the library of the Smithsonian Institution where he met Joseph Henry, the secretary of the Smithsonian. Henry allowed him to borrow the first volume of Bowditch’s translation of Laplace’s Mécanique céleste and Henry suggested that Newcomb look for a job at the Coast Survey. He was recommended to the Nautical Almanac Office in Cambridge, Massachusetts. A few weeks after coming to Cambridge, he was given a trial appointment as an astronomical computer. At the same time, he took time to study more mathematics at the Lawrence Scientific School of Harvard University under Benjamin Peirce. He graduated the next year in 1858.

            When the Civil War broke out in 1861, some of the professors of mathematics attached to the U.S. Navy resigned. This allowed Newcomb to take up the spot at the Naval Observatory. His job was to help in observing the right ascensions of stars with the transit circle. He hated randomly observing stars. When he was put in charge of the mural circle in 1863, he suggested to Superintendent Gilliss to have the right ascension and declination observations done more systematically. In 1865, a new transit circle was obtained and Newcomb took this opportunity to start a four-year program of fundamental observations of stellar positions. He became very interested in the theory behind the orbits of the planets and the moon. He hoped to improve their predicted positions by calculating the disturbances in their orbits caused by the gravitational pull of other objects.

            Looking over Hansen’s tables on the moon, he saw that the moon was starting to stray from its predicted position. Hansen had made these tables with observations dating back to 1750. Newcomb went to France to gather even older information about these observations. When Newcomb studied the pre-1750 data, he found that Hansen’s tables had many errors for the period before 1750. He believed that the aberration was due to variations in the rate of rotation of the Earth during that time. However his attempt to verify his theory from observing transits of Mercury was inconclusive. During the last years of his life, he tried again to take up this problem. His discussion of lunar observations from 720 B.C. to A.D. 1908 was completed a month before his death. The discussion he had written was left for others to prove that the fluctuations were caused by Earth’s irregular rotation.

            He also devoted two years to observe the satellites of Uranus and Neptune. From his observations and research, which were published in a memoir on The Uranian and Neptunian Systems, it appeared that the orbits of all four of Uranus’s satellites are circular. He also calculated the mass of Uranus and Neptune and verified his earlier predictions of Uranus’s mass.

            At an international conference in Paris in 1896 whose purpose was to elaborate a common system of constants and fundamental stars to be used in the various national tables and almanacs, Newcomb was a strong leader. He took up the task of determining a definite value of the constant of precession, and of aggregating a new catalogue of standard stars. The results of these investigations were published in 1899, and have been used since the beginning of 1901.

            Simon Newcomb had many accomplishments in his lifetime and published many books and papers on various topics. On July 11, 1909, he died in Washington. Because he was made a rear-admiral by Act of Congress in 1906, he was given a military funeral and was buried in Arlington Cemetery.

Works Cited

• "Newcomb, Simon." Complete Dictionary of Scientific Biography. Vol. 10. Detroit: Charles Scribner's Sons, 2008. 33-36. Gale Virtual Reference Library. Web. 17 Feb. 2011. 
• O'Connor, J. J., and E. F. Robertson. "Newcomb Biography." MacTutor History of Mathematics. Oct. 2003. Web. 13 Feb. 2011. <http://www-history.mcs.st-and.ac.uk/history/Biographies/Newcomb.html>.
• "Simon Newcomb." NNDB: Tracking the Entire World. Soylent Communications, 2011. Web. 19 Feb. 2011. <http://www.nndb.com/people/473/000103164/>.

APOD 3.5

Simeis 147: Supernova Remnant

(2011 February 12)

This picture shows the supernova remnant Simeis 147, also cataloged as Sh2-240. It is near the constellation Taurus and it is huge. It covers almost 3 degrees in the sky which is the equivalent of 6 full moons. It is 3,000 light-years long and 150 light-years wide. This picture is a composite and it had image data taken through narrow band filters to highlight emission from hydrogen and oxygen atoms tracing regions of shocked, glowing gas. It is estimated to be about 40,000 years old and what was also left behind is a spinning neutron star or pulsar. This is all that remains of the star's core after the explosion.

Supernovas are one of the most violent events in the universe. The force of the explosion creates a blinding flash of radiation and shock waves comparable to sonic booms. Supernovas are classified by their optical properties. Massive stars spend their lives burning nuclear fuel and nuclei of light elements like hydrogen and helium are combined to make heavier elements like carbon and oxygen in a progression which ends with iron. When a supernova explosion occurs, the explosion blasts these heavier elements back into space. The elements and hot temperature creates the color we see here.

Observation (2/17/11)

Yesterday night at 8 pm I went out to see the moon and the stars on my driveway. The moon was full up above in the east and it was very bright. It was cloudy but there were some empty spaces in the sky where you can see some stars and constellations. It was fairly bright so the stars were faint. I could see Orion and his belt in the south. Trying to draw out the "heavenly G" I could make out, from the east to south, Castor, Pollux, Procyon, Rigel, then up to Betelgeuse. Up above in the north, I could not make out any constellations, but there was a bright star where Auriga should be so I suspected that it was Capella.

Sources for Simon Newcomb

• "Newcomb, Simon." Complete Dictionary of Scientific Biography. Vol. 10. Detroit: Charles Scribner's Sons, 2008. 33-36. Gale Virtual Reference Library. Web. 17 Feb. 2011.

• O'Connor, J. J., and E. F. Robertson. "Newcomb Biography." MacTutor History of Mathematics. Oct. 2003. Web. 13 Feb. 2011. <http://www-history.mcs.st-and.ac.uk/history/Biographies/Newcomb.html>.

Observation (2/17/11)

I went out this morning at 6:10 am on my driveway. The skies were clear. I could see Venus, which was very bright in the south-east. To the right of Venus, I could see Scorpius and Antares. The scorpion was oriented vertically up and down. Up above near the north, I could see the big dipper. As we learned in starlab, I followed the handle and I was able to locate Arcturus which was also bright.

Observation (2/15/11)

Tonight, I went out for observations around 9:10 pm. The skies were very clear, there were no clouds and I was on my driveway in Osprey. The moon was very bright. It was a waxing gibbous and it was almost full. It was right above a little to the east. When I was standing facing the moon, this time I was sure that the two stars to the left of the moon were Castor and Pollux because I checked the star charts. There were not as many stars visible however because the moon was so bright. Sirius could also be seen and I could make out the shape of the dog with his back, tail, and two legs. Nearby, as always, was Orion clearly visible with his belt and dagger and Betelgeuse with the reddish shine above in the south. Above in the southwest was a bright star, and from the previous constellations we learned this quarter, I believe that star was Aldebaran from the constellation Taurus although I was not able to see the shape of the bull.

APOD 3.4

Star Colors in Orion (11 Feb. 2011)

This picture shows the stars in the constellation Orion. This photograph shows the stars kind of smeared out because the photographer used a photographing technique called a step-focus technique. This technique requires the photographer to take a series of 35 consecutive exposures. When combined, these exposures make trails of stars moving from left to right through the frame that changes focus in steps. Starting and ending with the camera out of focus makes a sharply focused exposure near the middle of the series which is why it resembles the shape of a bowtie. In the upper left, is the red supergiant Betelgeuse. Below center is the pinkish Orion Nebula, and near the center right edge is W Orionis.

This picture was interesting because it's related to what we just learned in class, how stars are different colors and why. The red stars, like Betelgeuse, appear red because they are cool. They have surface temperatures around 3,000 K. Blue stars are hotter and have temperatures over 30,000 K. But it's size and distance away affects how bright it actually appears to us. It was also interesting to learn about this photographing technique and how they photograph stars to see their true colors. In this photograph, you can easily distinguish the different colors of the stars and how bright they appear. Although, there may also be other factors that contribute to the color like W Orionis. It's red color is enhanced by it's carbon-rich composition.

Observation (2/8/11)

Location: My driveway in Osprey
Time: 8:30 P.M.
Weather Conditions: Clear skies

Tonight I was able to have a good clear view of the sky. The moon was visible in the west. It was a bright waxing crescent. In the north, I was able to see the Ursa Minor and Polaris. It was faint so I had to block the lights from my house with my hands to be able to see it. Orion was visible up above and I was able to see Orion's belt and the stars that make up his dagger. Sirius could also be seen to the lower left. There were also a few more bright stars even more left of it that I believe could have been Castor and Pollux.

APOD 3.3

Zeta Oph: Runaway Star (4 Feb. 2011)

This picture is of a runaway star named Zeta Oph, which can be located in the constellation Ophiuchus. A runaway star is a massive star that travels rapidly through interstellar space. Because it is rapidly traveling throught interstellar space at 24 km/sec, Zeta Oph created the arcing interstellar bow wave or bow shock seen in the picture. That is the orange/reddish arc that can be seen in the center of the picture. Zeta Oph is the blue shining point that is located in the arc. As seen from this picture, it should be moving towards the top of this frame. This star is moving through interstellar material. Interstellar material is the material which fills the space between the stars. These areas have very little matter in them and mainly consists of gas and dust, which is what we've learned about in class. There may be a small amount of dust particles per cubic cm, but with the great distances between the stars, the number of dust particles really add up.

With Zeta Oph, it has strong stellar winds that precede it. These winds compress and heat the dusty interstellar material and shapes the curved shock front. 

The thing that actually started to make this a runaway star was the explosion of its companion when it was in a binary star system. Because it's  companion star was much larger, it had a shorter life span. A star's life cycle is determined by its mass. The bigger it is the shorter its life cycle. When it's companion exploded as a supernova, this explosion propelled Zeta Oph through the system. It was actually flung 460 light-years away and it is actually 65,000 times more luminous than the sun. However as we learned that the numbers of dust particles add up through space and dust is like fog, this explains why this dust surrounded star isn't one of the brightest in the sky.