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Maxima of the long period variable star Omicron Ceti (Mira) on the 21-31 August, 2012. 

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Title: Is Mira a magneto-dusty rotator?
Authors: Anand Thirumalai, Jeremy S. Heyl

We investigate the possibility that a magnetic field may be present in the star o-Ceti (hereafter, Mira) and that the field plays a role in the star's mass loss. The model presented here is an application of an earlier derived theory that has been successfully employed for intermediate and high-mass evolved stars, and is now extended to the low-mass end. The modelling shows that it is possible to obtain a hybrid magnetohydrodynamic-dust-driven wind scenario for Mira, in which the role of a magnetic field in the equatorial plane of the star is dynamically important for producing a stellar wind. The wind velocity and the temperatures obtained from the model appear consistent with findings elsewhere.

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Mira - the wonderful star: Eyes on the Sky


Video aimed at northern hemisphere observers about the variable star Mira in the constellation Cetus, that has recently peaked in brightness.
Mira is at it's brightest this peak, at around magnitude 2.1 in October of 2011. It will decrease by about one magnitude per month, likely diminishing to it's typical low magnitude of around 9.



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Google earth file: Mira.kmz (2kb, kmz)



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RE: Mira AB
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Contemporary approximate maxima for Mira:

  • Oct 21-31, 1999
  • Sep 21-30, 2000
  • Aug 21-31, 2001
  • Jul 21-31, 2002
  • Jun 21-30, 2003
  • May 21-31, 2004
  • Apr 11-20, 2005
  • Mar 11-20, 2006
  • Feb 1-10, 2007
  • Jan 21-31, 2008
  • Dec 21-31, 2008
  • Nov 21-30, 2009
  • Oct 21-31, 2010
  • Sep 21-30, 2011
  • Aug 21-31, 2012
  • Jul 21-31, 2013
  • Jun 21-31, 2014
  • May 21-31, 2015


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Maxima of long period variable star Omicron Ceti (Mira) on the 27th September, 2011.

Magnitude range: 2.0 - 10.1
Period: 332.0 days
Type: Mira        

Position(2000): RA 02 19 20.7927  |  Dec  -02° 58' 39.513"



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David Fabricius (March 9, 1564 - May 7, 1617) discovered the first known periodic variable star (as opposed to cataclysmic variables, such as novas and supernovas), Mira, in August of 1596. At first he believed it to be "just" another nova, as the whole concept of a recurring variable did not exist at the time. When he saw Mira brighten again in 1609, however, it became clear that a new kind of object had been discovered in the sky.
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Evidence that the variability of Mira was known in ancient China, Babylon or Greece is at best only circumstantial. What is certain is that the variability of Mira was recorded by the astronomer David Fabricius beginning on August 3, 1596. Observing the planet Mercury, he needed a reference star for comparing positions and picked a previously unremarked third-magnitude star nearby. By August 21, however, it had increased in brightness by one magnitude, then by October had faded from view. Fabricius assumed it was a nova, but then saw it again on February 16, 1609.
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Title: Herschel's view into Mira's head
Authors: A. Mayer, A. Jorissen, F. Kerschbaum, S. Mohamed, S. Van Eck, R. Ottensamer, J.A.D.L. Blommaert, L. Decin, M.A.T. Groenewegen, Th. Posch, B. Vandenbussche, C. Waelkens

Herschel's PACS instrument observed the environment of the binary system Mira Ceti in the 70 and 160 micron bands. These images reveal bright structures shaped as five broken arcs and fainter filaments in the ejected material of Mira's primary star. The overall shape of the IR emission around Mira deviates significantly from the expected alignment with Mira's exceptionally high space velocity. The observed broken arcs are neither connected to each other nor are they of a circular shape; they stretch over angular ranges of 80 to 100 degrees. By comparing Herschel and GALEX data, we found evidence for the disruption of the IR arcs by the fast outflow visible in both Halpha and the far UV. Radial intensity profiles are derived, which place the arcs at distances of 6-85" (550 - 8000 AU) from the binary. Mira's IR environment appears to be shaped by the complex interaction of Mira's wind with its companion, the bipolar jet, and the ISM.

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Title: Herschel's view into Mira's head
Author(s): A. Mayer, A. Jorissen, F. Kerschbaum, S. Mohamed, S. van Eck, R. Ottensamer, J.A.D.L. Blommaert, L. Decin, M.A.T. Groenewegen, Th. Posch, B. Vandenbussche, Ch. Waelkens

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Mira is a binary star, consisting of the red giant Mira A along with Mira B.
Mira A is also an oscillating variable star and was the first non-supernova variable star discovered, with the possible exception of Algol.

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The companion star Mira B, also known as VZ Ceti, can be resolved by a good quality 3" telescope.
The companion star is about 70 astronomical units from the primary; with an orbital period around Mira is approximately 400 years.
Mira B is a normal main sequence star of spectral type K and roughly 0.7 solar masses.

mira5.gif

Position(2000): RA 02 19 20.7927, Dec  -02 58 39.513

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