* Astronomy

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Supernova 2011fe

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Supernova 2011fe now starting to fade (being reported at magnitude 10.0).

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Date: 12th September, 2011.

Ed ~ The supernova is just too faint to be captured in this image (only down to magnitude 8)

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How to find M101 supernova - "Eyes on the Sky"

Ed ~ precise guide, with higher magnitude star hops, for telescopes.

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Date: 11th September, 2011.

(Copyright Free)

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Date: 11th September, 2011.

(Copyright Free)

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Supernova 2011fe now being reported at magnitude 9.9

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Supernova 2011fe is now at magnitude 10.0

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Simple star hop to find M101:

With a very low powered eyepiece (the lowest you can go) locate the constellation Ursa Major (Great Bear, or the Big Dipper).

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1) Find Mizar-Alcor, the binary stars in the constellation Ursa Major.
North of Mizar are a chain of 4 stars visible in a viewfinder.
2) Use the position and angle of Mizar-Alcor to find star 81 on the chart.
3) From star 81 hop to star 83
4) From star 83 hop to star 84
5) From star 84 hop to star 86
6) From star 86, M101 is at an angle of ~120 degrees (a third of a circle) from star 84 - and about the same distance as star 84 to star 86.

Also the two main stars (the handle of the Dipper or the Great Bear's tail) of Ursa Major form a nice equilateral triangle with M101. If your finder is correctly aligned then you can then centre it exactly on the corner where the galaxy should be.

The center of the galaxy should appear as faint fuzzy star in smaller telescopes, (and use the images of the galaxy to find the supernova...)

See also Star Hopping

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Title: Constraints on the Progenitor System of the Type Ia Supernova SN 2011fe/PTF11kly
Authors: Weidong Li, Joshua S. Bloom, Philipp Podsiadlowski, Adam A. Miller, S. Bradley Cenko, Saurabh W. Jha, Mark Sullivan, D. Andrew Howell, Peter E. Nugent, Nathaniel R. Butler, Eran O. Ofek, Mansi M. Kasliwal, Joseph W. Richards, Alan Stockton, Hsin-Yi Shih, Lars Bildsten, Michael M. Shara, Joanne Bibby, Alexei V. Filippenko, Mohan Ganeshalingam, Jeffrey M. Silverman, S. R. Kulkarni, Nicholas M. Law, Dovi Poznanski, Robert M. Quimby, Curtis McCully, Brandon Patel, Kate Maguire

Type Ia supernovae (SNe) serve as a fundamental pillar of modern cosmology, owing to their large luminosity and a well-defined relationship between light-curve shape and peak brightness. The precision distance measurements enabled by SNe Ia first revealed the accelerating expansion of the universe, now widely believed (though hardly understood) to require the presence of a mysterious "dark" energy. General consensus holds that Type Ia SNe result from thermonuclear explosions of a white dwarf (WD) in a binary system; however, little is known of the precise nature of the companion star and the physical properties of the progenitor system. Here we make use of extensive historical imaging obtained at the location of SN 2011fe/PTF11kly, the closest SN Ia discovered in the digital imaging era, to constrain the visible-light luminosity of the progenitor to be 10-100 times fainter than previous limits on other SN Ia progenitors. This directly rules out luminous red giants and the vast majority of helium stars as the mass-donating companion to the exploding white dwarf. Any evolved red companion must have been born with mass less than 3.5 times the mass of the Sun. These observations favour a scenario where the exploding WD of SN 2011fe/PTF11kly, accreted matter either from another WD, or by Roche-lobe overflow from a subgiant or main-sequence companion star.

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