Information of Supernovas

Hello teacher Marsella!!!!
This week we couldn't work on the Mediateca because it wasn't on service.

I worked on my house with Diana and this is our information:

The supernovas are heavenly bodies that are on explosion danger. If a supernova explodes with it, can cause the origin of a new start. The Big Bang was a Supernova that origin the Solar sistem and that is important for us.
We will talk about the Solar Sistem origin:
When the Universe have just stars and doesn't exist planets, have a big explosion caused for a star. This explosion caused a big cloud of gas and cosmic powder. These materials were joined together to create the planets and their satellites. This formation create the Milk way and
the life on the third planet of the Solar Sistem: "the Earth."
It's fabolous for us to know that the Earth was a “trash” of the space and then it was the result of a Supernova. We think that the life on the Earth is fantastic and his history is very important for all the people that live in this planet.
Well…this could be the introduction of our work and we go to work on a presentation in Power Point.
Our bibliography is:
O., Monticelli, New Tematic Encyclopaedia, Paraguay, Richards editorial, 7ª edition, 535 pages, 1967.
Ríos, Magdalena, Atlas Universal and of México, Mexico DF, Trillas editorial, 96 pages, 2001.
Mitchell Beazley Encyclopaedias Limited, The Eartht, Spain, Salvat editorial, 125 pages, 1985.
Content:
A supernova is a stellar explosion that creates an extremely luminous object. A supernova causes a burst of radiation that may briefly outshine its entire host galaxy before fading from view over several weeks or months. During this short interval, a supernova can radiate as much energy as the Sun would emit over 10 billion years.This is so surprising; can you ever imagine this power that has the supernovas?The explosion throws materials a velocity of up to a tenth the speed of light, driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant.Several types of supernovae exist that may be triggered in one of two ways, involving either turning off or suddenly turning on the production of energy through nuclear fusion. After the core of an aging massive star ceases to generate energy from nuclear fusion, it may undergo sudden gravitational collapse into a neutron star or black hole, releasing gravitational potential energy that heats and expels the star's outer layers.Supernova in other galaxies cannot be predicted with any meaningful accuracy. When they are discovered, they are already in progress. Most scientific interest in supernovae—as standard candles for measuring distance, for example—require an observation of their peak luminosity. It is therefore important to discover them well before they reach their maximum. Amateur astronomers, who greatly outnumber professional astronomers, have played an important role in finding supernovae, typically by looking at some of the closer galaxies through an optical telescope and comparing them to earlier photographs.Supernova searches fall into two classes: those focused on relatively nearby events and those looking for explosions farther away. Because of the expansion of the universe, the distance to a remote object with a known emission spectrum can be estimated by measuring its Doppler shift (or redshift); on average, more distant objects recede with greater velocity than those nearby, and so have a higher redshift. Thus the search is split between high redshift and low redshift, with the boundary falling around a redshift range of z = 0.1–0.3—where z is a dimensionless measure of the spectrum's frequency shift.Tape AOne model for the formation of this category of supernova is a close binary star system. The larger of the two stars is the first to evolve off the main sequence, and it expands to form a red giant. The two stars now share a common envelope, causing their mutual orbit to shrink. The giant star then sheds most of its envelope, losing mass until it can no longer continue nuclear fusion. At this point it becomes a white dwarf star, composed primarily of carbon and oxygen. Eventually the secondary star also evolves off the main sequence to form a red giant. Matter from the giant is accreted by the white dwarf, causing the latter to increase in mass.TYPE BThese events, like supernovae of Type II, are probably massive stars running out of fuel at their centers; however, the progenitors of Types Ib and Ic have lost most of their outer (hydrogen) envelopes due to strong stellar winds or else from interaction with a companion. Type Ib supernovae are thought to be the result of the collapse of a massive Wolf-Rayet star. There is some evidence that a few percent of the Type Ic supernovae may be the progenitors of gamma ray bursts (GRB), though it is also believed that any hydrogen-stripped, Type Ib or Ic supernova could be a GRB, dependent upon the geometry of the explosion.Impact on EarthA near-Earth supernova is an explosion resulting from the death of a star that occurs close enough to the Earth (roughly fewer than 100 light-years away) to have noticeable effects on its biosphere. Gamma rays are responsible for most of the adverse effects a supernova can have on a living terrestrial planet. In Earth's case, gamma rays induce a chemical reaction in the upper atmosphere, converting molecular nitrogen into nitrogen oxides, depleting the ozone layer enough to expose the surface to harmful solar and cosmic radiation. The gamma ray burst from a nearby supernova explosion has been proposed as the cause of the end Ordovician extinction, which resulted in the death of nearly 60% of the oceanic life on Earth.Speculation as to the effects of a nearby supernova on Earth often focuses on large stars as Type II supernova candidates. Several prominent stars within a few hundred light years from the Sun are candidates for becoming supernovae in as little as a millennium. One example is Betelgeuse, a red supergiant 427 light-years from Earth. Though spectacular, these "predictable" supernovae are thought to have little potential to affect Earth.Recent estimates predict that a Type II supernova would have to be closer than eight parsecs (26 light-years) to destroy half of the Earth's ozone layer.Such estimates are mostly concerned with atmospheric modeling and considered only the known radiation flux from SN 1987A, a Type II supernova in the Large Magellanic Cloud. Estimates of the rate of supernova occurrence within 10 parsecs of the Earth vary from once every 100 million years to once every one to ten billion years.Type Ia supernovae are thought to be potentially the most dangerous if they occur close enough to the Earth. Because Type Ia supernovae arise from dim, common white dwarf stars, it is likely that a supernova that could affect the Earth will occur unpredictably and take place in a star system that is not well studied. One theory suggests that a Type IA supernova would have to be closer than a thousand parsecs (3300 light-years) to affect the Earth.

Opinion:We think this is an incredible topic, it had a lot of information, and it gave me surprised, of the power of supernovas have, this is incredible.Well, we want also to make a type of presentation, because the images that we got were annoyed.I think the world of the universe is amazing.

Welll teacher, this was we work. See you next class.

Homework: Supernovas

Hello teacher Marsella. Well this we work of the Supernovas. This is some information about the Supernovas .

INTRODUCTION

We choose the topic of Supernova because we think that the universe is another world in which we represent a minimum part of that whole world. The origin of the universe is the most important for us because we live here, so we are going to talk about the Supernovas.
These heavenly bodies are the cause of the live in the Earth because the explosion of the Big Bang was a supernova.

CONTENT

The supernovas are stars in explosion danger that to produce a fusion of elements on the interior of the start that can to create an extremely luminous object. The explosion of a supernova can cause a new start. These are the origin of a dark hole, too. The results of this explosion are wonderful: the explosion cause a big energy center that is as the solar energy for ten years. Is incredible the energy that a star have.
The supernovas have a “little sisters” that are the novas. This heavenly bodies are stars very bright that have cosmic powder in it interior. When this bodies to exploit, can be brigthest.
The supernovas are classifying in:
TIPE I:. This tipe include at the supernovas of tipe Ia, Ib and Ic.
Tipe Ia: it is the explosion of the little stars of white color. These supernovas haven’t Hydrogen and have ions of silicon.
Tipe Ib: it haven’t Helio.
Tipe Ic: the Helio that is in it interior is weak or don’t exist and cause the gamma rays.
TIPE II: are the stars with 9 times the solar mass.

The supernovas are importants in we life because the universe origin was caused for this heavenly body. Remember that the Big- Bang explosion was a shok between two planets and it material was dispersed for all the space and cause the accumulation of this material for the trainig of news planets.

CONCLUSION

Well, the Supernovas are importants for we because the Universe was origined for a explosion of this tipe and because the contact with the Earth can cause a big production of energy that cause damage the normal functioning of the electric things in the continents.

Well, I think that it's good and see you next class teacher.

P.S. I chose the topic of Supernovas because I think that the Universe origin is the most important in the life of the humans. The cause of the explosion called Big Bang is the content of this topic because this explosion was a Supernova.
This work like me very much because the life is a mistery and all we have that ask these questions.

Web pages about the Supernovas

Hello teacher Marsella. I'm writig to talk about my topic. My favoritre topic was Supernovas and like me because I love things that are out the Earth. The astronomy is my favorite Science because I think that the Universe creation is a thing important in the life of each human. The Web page that we (Diana and me) search were:
www.en.wikipedia.org/wiki/Supernova
www.heasarc.gsfc.nasa.gov/docs/snr.html
www.space.com/supernovas/
www.chandra.harvard.edu/xray_sources/supernovas.
www.nmm.ac.uk/server/show/conWebDoc.300
www.science.nasa.gov/headlines/y2003/06jan_bubble.htm
http://www.corsacentre.com/
www.space.com/scienceastronomy/060220_mm_sound_supernova.html
www.harvard.edu/cfa/oir/Research/supernova/highz/figures/index.html
www.supernovae.net/snimages/snlinks.html
www.cfa.harvard.edu/supernova/SNlinks.html
Well teacher, this was my homework. See you next class.Have a nice day

Supernova

November 1, 2007
Christine PulliamHarvard Smithsonian Center for Astrophysics
Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have found that a supernova discovered last year was caused by two colliding white dwarf stars. The white dwarfs were siblings orbiting each other. They slowly spiraled inward until they merged, touching off a titanic explosion. CfA observations show the strongest evidence yet of what was, until now, a purely theoretical mechanism for creating a supernova.
"This finding shows that nature may be richer than we suspected, with more than one way to make a white dwarf explode," said Harvard graduate student and first author Malcolm Hicken.
The paper describing this discovery appeared in the November 1st issue of The Astrophysical Journal Letters.
Astronomers characterize an observed supernova based on whether its spectrum shows evidence of hydrogen (Type II) or not (Type I). In Type II, a massive, short-lived star undergoes core collapse and explodes. In the conventional picture for Type Ia, the most common supernovae lacking hydrogen, a white dwarf star collects gas from a companion star until it undergoes catastrophic nuclear fusion and blasts itself apart.
The new find, supernova 2006gz, was classified as a Type Ia due to the lack of hydrogen and other characteristics. However, an analysis combining CfA data with measurements from The Ohio State University suggested that SN 2006gz was unusual and deserved a closer look.
Most importantly, SN 2006gz showed the strongest spectral signature of unburned carbon ever seen. Merging white dwarfs are expected to have carbon outside their densest regions. The powerful explosion from the inside then should push off the outmost carbon-rich layers.
The spectrum of SN 2006gz also showed evidence for compressed layers of silicon. Silicon was created during the explosion and then compressed by a shock wave that rebounded from the surrounding layers of carbon and oxygen.
Computer models for merging white dwarfs predict both the carbon and silicon spectral signatures.
Additionally, SN 2006gz was brighter than expected, indicating that its progenitor exceeded the 1.4 solar mass Chandrasekhar limit - the upper bound for a single white dwarf. Only one other potential example of a super-Chandrasekhar supernova has been seen: SN 2003fg. While observations of that event were suggestive, the data from SN 2006gz are much stronger.
"Our case is different. Although 2006gz is also extra bright, the chemistry we see, particularly unburned carbon, is well observed and very unusual," said Harvard astronomer Robert Kirshner, a member of the discovery team.
In addition to providing the first example of a new way to make supernovae, SN 2006gz holds implications for the field of cosmology. Type Ia supernovae typically have a narrow spread in brightness, which makes them useful as "standard candles" for calculating cosmic distances. It was the study of Type Ia supernovae that led to the discovery of dark energy, the mysterious force causing the expansion of the universe to accelerate.
If Type Ia supernovae are more varied than previously expected, then astronomers must be extra cautious when using them to study the cosmos.
"Supernova 2006gz stands out from normal Type Ia objects and wouldn't be included in cosmology studies," commented Hicken. "But we have to be careful not to mistake a double white dwarf explosion for a single white dwarf blast. SN 2006gz was easy to recognize, but there may be less clear-cut cases."
The full list of authors of the study is: Malcolm Hicken, Stéphane Blondin and Robert Kirshner (CfA); Peter Garnavich (University of Notre Dame); Jose Prieto and Darren DePoy (The Ohio State University); and Jerod Parrent (University of Oklahoma). This research was supported by the National Science Foundation.