Life cycle of a star?!?!!?!?

 
     This is an image of a stellar nursery, from these cold clouds of stellar matter protostar form as they collapse under gravitational disturbances.that is it will stay the same until the kinetic energy is balanced with
the potential energy of the internal gravitational field.
     when these protostars start to collapse and the pressure and temperature the cloud, it starts to form a disc
and nuclear reactions start to take place.
  At this point some protostars are rather too small and don't achieve nuclear reactions and are called failed stars or brown dwarfs.
  All the other protostars which have achieved nuclear reactions show very unstable behaviour like rapid rotation strong wind and eject a lot of nuclear materials at the poles and slowly stabilise.
  In stars have more than about 0.08 solar masses form a star having nuclear reactions. The core of the stars literally start collecting the stellar clouds during this time some of the hot nuclear substance fly off to form planets which individually start collecting the stellar clouds around them. After this formation of stars and planets, the stars , enter the main sequence, every star spends about 90% of their life in this stage.

•  Stars lesser than 1 solar mass collapse to form a dim black dwarf.
•  Sun like stars (1solar mass) evolve or more precisely get swollen to form a red giant, the outer layers  form the planetary nebulae the heavy elements now help the core to become a white dwarf  which will  be inside the planetary nebulae.
• Stars having more than 8 solar masses evolve in a super giant, explodes as a supernova, smaller  remnants become neutron star or stars that are of almost the size of earth and larger remnants become a black 

          know more on black holes

       Here is a video from nasa.gov ,

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Newly Discovered Supermassive Black Hole --"Defies Theories of Galaxy-Size Limits"

The central supermassive black hole of a recently discovered galaxy is far larger than should be possible, according to current theories of galactic evolution. New work, carried out by astronomers at Keele University and the University of Central Lancashire, shows that the black hole is much more massive than it should be, compared to the mass of the galaxy around it. The scientists publish their results in a paper in Monthly Notices of the Royal Astronomical Society.

The galaxy, SAGE0536AGN, was initially discovered with NASA's Spitzer space telescope in infrared light. Thought to be at least 9 billion years old, it contains an active galactic nucleus (AGN), an incredibly bright object resulting from the accretion of gas by a central supermassive black hole. The gas is accelerated to high velocities due to the black hole's immense gravitational field, causing this gas to emit light.

The team has now also confirmed the presence of the black hole by measuring the speed of the gas moving around it. Using the Southern African Large Telescope, the scientists observed that an emission line of hydrogen in the galaxy spectrum (where light is dispersed into its different colours – a similar effect is seen using a prism) is broadened through the Doppler Effect, where the wavelength (colour) of light from objects is blue- or red-shifted depending on whether they are moving towards or away from us. The degree of broadening implies that the gas is moving around at high speed, a result of the strong gravitational field of the black hole.

Is this the most distant object ever discovered??????

In search of objects from the early universe,a team of Caltech researchers after many years of research have found some things which could be the most distant galaxy.In an article published August 28, 2015 in Astrophysical Journal Letters, Adi Zitrin, a NASA Hubble Postdoctoral Scholar in Astronomy, and Richard Ellis--who recently retired after 15 years on the Caltech faculty and is now a professor of astrophysics at University College, London--describe evidence for a galaxy called EGS8p7 that is more than 13.2 billion years old. The universe itself is about 13.8 billion years old.Earlier this year, EGS8p7 had been identified as a candidate for further investigation based on data gathered by NASA's Hubble Space Telescope and the Spitzer Space Telescope. Using the multi-object spectrometer for infrared exploration (MOSFIRE) at the W.M. Keck Observatory in Hawaii, the researchers performed a spectrographic analysis of the galaxy to determine its redshift. Redshift results from the Doppler effect, the same phenomenon that causes the siren on a fire truck to drop in pitch as the truck passes. With celestial objects, however, it is light that is being "stretched" rather than sound; instead of an audible drop in tone, there is a shift from the actual color to redder wavelengths.

Redshift is traditionally used to measure distance to galaxies, but is difficult to determine when looking at the universe's most distant--and thus earliest--objects. Immediately after the Big Bang, the universe was a soup of charged particles--electrons and protons--and light (photons). Because these photons were scattered by free electrons, the early universe could not transmit light. By 380,000 years after the Big Bang, the universe had cooled enough for free electrons and protons to combine into neutral hydrogen atoms that filled the universe, allowing light to travel through the cosmos. Then, when the universe was just a half-billion to a billion years old, the first galaxies turned on and reionized the neutral gas. The universe remains ionized today.

Prior to reionization, however, clouds of neutral hydrogen atoms would have absorbed certain radiation emitted by young, newly forming galaxies--including the so-called Lyman-alpha line, the spectral signature of hot hydrogen gas that has been heated by ultraviolet emission from new stars, and a commonly used indicator of star formation.

Because of this absorption, it should not, in theory, have been possible to observe a Lyman-alpha line from EGS8p7.

A graphic representation below of the extreme distance of galaxy EGS8p7. To the far right is theW. M. Keck telescope used for the observation, to the far left is the Big Bang, and at the center is the galaxy. The scale above indicates the progression of ever more distant discoveries and the corresponding year, and at the bottom is a time scale equivalent to distance. Finally, the inset to top left charts the observations made across two nights with the MOSFIRE spectrometer that resulted in the detection. (Adi Zitrin/ Caltech).

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via:dailygalaxy.com