Essay About Type Ia Supernova And Stars Balance

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1. What are the Roche lobes of a close binary star system? What is the significance of the pointwhere the two lobes “touch” each other, and what can happen there?The “Roche lobes” are the surfaces where the effects of the two stars balance. Anything at the “inner Lagrangian point,” L1, feels equal effects from both stars. Now the star of the show is L1 , the “inner Lagrangian point.” This is the place where the mass flows through from the Roche lobe of the donor star, to the star that receives the mass. Matter moving away from one star that reaches the “inner Lagrangian point” of gravity balance between the two stars can be captured by the other star. • If the companion is a normal star, such as Main Sequence star, it is large enough to intercept the mass stream and collect the transferred mass. 2. Why does the mass transferred from a star to a compact companion end up orbiting thecompact object in a so-called “accretion disk”? What kind of radiation does the disk emit?Things get interesting when the companion is a compact object. The latter object’s mass is squeezed inside a small radius, leaving lots of space for the transferred mass to collect in a swirling accretion disk. The compact object may be a white dwarf, neutron star, or black hole. The accretion disk, which radiates optical light, can be the brightest thing in the system. Roughly regular brightness variations may be seen as the distorted companion star (with a hotter “disk-facing” side) orbits the center of mas and the “hot spot” cycles in and out of view. 3. What happens in a classical nova event? What causes a “thermonuclear” or Type Ia supernova?What type of compact star is present in both cases, and what happens to it?Classical novae are much brighter than disk instabilities. • They run nuclear fusion reactions up to the light alpha elements like Ne and Mg; they may also blast off some of the material from the white dwarf. • But they do not destroy the white dwarf, so after the system settles down, mass transfer can resume, and eventually another nova explosion can occur. -White dwarf or “thermonuclear” supernova: If so much mass accumulates on the white dwarf that its mass exceeds the Chandrasekhar limit of 1.4 M! , the WD will explode. This is called a “Type Ia” supernova, and is a very different phenomenon from a core-collapse supernova. White dwarf is present in both cases.

4. What discovery about the expansion of the universe was made using Type Ia supernovae?Why were Type Ia supernovae useful in making this discovery?Observations of Type Ia SNe indicate that the universe is actually expanding faster today than it was in the past. This is unexpected, since the influence of both luminous and dark matter should slow down the expansion. The Accelerating Universe The unknown agent that causing the acceleration has come to be called dark energy.5. Describe the components of a so-called “X-ray binary” system. How can we tell whether sucha system contains a neutron star or a black hole?The X-rays are produced by matter falling from one component, called the donor (usually a relatively normal star), to the other component, called the accretor, which is very compact: a neutron star or black hole. The infalling matter releases gravitational potential energy, up to several tenths of its rest mass, as X-rays. The lifetime and the mass-transfer rate in an X-ray binary depends on the evolutionary status of the donor star, the mass ratio between the stellar components, and their orbital separation. It’s a black hole if it’s not an ordinary star and its mass exceeds the neutron star limit (~2 M!)6. Explain why the composition of the interstellar medium (ISM) is changing with time and, inparticular, the concentration of elements heavier than H and He keeps increasing.Stars make new elements by fusion reactions • Dying stars expel gas and new elements, producing hot bubbles in the ISM (~106 K) • The hot gas cools, allowing atomic hydrogen clouds to form (~100-10,000 K) • Further cooling permits molecules to form, making molecular clouds (~30 K) • Gravity forms new stars (and planets) in cold molecular clouds7. What are the effects of dust grains on starlight passing through interstellar clouds? Where didthe dust come from?Mixed with the gas are multitudes of tiny solid particles called “astrophysical dust” or “dust grains.” These are heated by stars and motions, and radiate as thermal emitters, producing radiation mostly in the infrared range. At short wavelengths, they block light passing through. Dust clouds cut down its brightness by a factor of 10128. What kinds of electromagnetic radiation (what spectrum region) is emitted by interstellar dust

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“Harvard Law Case” EssaysForStudent.com. 02 2017. 2017. 02 2017 < "Harvard Law Case." EssaysForStudent.com. EssaysForStudent.com, 02 2017. Web. 02 2017. < "Harvard Law Case." EssaysForStudent.com. 02, 2017. Accessed 02, 2017. Essay Preview By: lkajdsfkldsj Submitted: February 12, 2017 Essay Length: 1,989 Words / 8 Pages Paper type: Case Study Views: 413 Report this essay Tweet Related Essays Employment Law Case Pertaining to Race #Employment Law Case Pertaining to Race Title VII’s prohibitions apply regardless of whether the discrimination is directed at Whites, Blacks, Asians, Latinos, Arabs, Native 279 Words  |  2 Pages Real Madrid Marketing Harvard Business Case Florentino Perez had been elected for the second times in June 2000 as the president of Real Madrid. Perez had promised to turn around the 429 Words  |  2 Pages Keeping It to the Fairway - Harvard Business Case Keeping to the Fairway The Keeping to the Fairway case study is a complex situation that needs to be handled in the correct manner. At 1,223 Words  |  5 Pages Contract Law Case Study E-Business Contract Law Case Study Analysis I. My first gut was to say that this was a contract. The website made an offer to send 354 Words  |  2 Pages Similar Topics Case Study Gerber Babyfoods Environmental Law Case Study Get Access to 89,000+ Essays and Term Papers Join 209,000+ Other Students High Quality Essays and Documents Sign up © 2008–2020 EssaysForStudent.comFree Essays, Book Reports, Term Papers and Research Papers Essays Sign up Sign in Contact us Site Map Privacy Policy Terms of Service Facebook Twitter