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TOPIC: Epsilon Aurigae


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Title: On the discovery of K I 7699 A line strength variation during the 1982 - 1984 eclipse of Epsilon Aurigae
Author: Mudumba Parthasarathy

The discovery of K I 7699{\AA} line strength variations during the 1982-1984 eclipse of epsilon Aurigae is described. The equivalent widths and radial velocities of the K I 7699{\AA} line derived from spectra obtained during 1981 November to 1983 July with the 2.1-meter Otto Struve reflector telescope of the McDonald observatory are presented.

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Title: A new look into the spectral and light variations of epsilon Aur
Authors: P. Harmanec, H. Boic, D. Korcáková, L. Kotková, P. koda, M. lechta, M. vanda, V. Votruba, M. Wolf, P. Zasche, A. Henden, J. Ribeiro

Investigating long series of spectral and photometric observations, we found that the orbital elements of epsilon Aur are subject to much larger uncertainties than usually believed. The H alpha emission is found to move basically with the F primary but its exact location should still be investigated. We also find strong additional absorption and large reddening of the object near the third contact during the eclipse. Episodic atmospheric mass transfer from the F primary towards its companion is tentatively suggested.

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Title: H alpha spectral monitoring of epsilon Aurigć 2009-2011 eclipse
Authors: B. Mauclaire, C. Buil, T. Garrel, R. Leadbeater, A. Lopez

We present and analyse epsilon Aurigae data concerning the evolution of the H{\alpha} line on the occasion of the 2009 International observation campaign launched to cover the eclipse of this object. We visually inspect the dynamical spectrum constructed from the data and analyse the evolution with time of the EW (Equivalent Width) and of the radial velocity. The spectroscopic data reveal many details which confirm the complexity of the Aurigae system. The object is far from being understood. In particular, according to our measurements, the eclipse duration has been underestimated. A complete analysis of details revealed by our data would require much time and effort. Observers are encouraged to continue monitoring the H{\alpha} line out of eclipse in the hope that it will provide further important information.

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Title: The Invisible Monster Has Two Faces: Observations of Epsilon Aurigae with the Herschel Space Observatory
Authors: D. W. Hoard, D. Ladjal, R. E. Stencel, S. B. Howell

We present Herschel Space Observatory photometric observations of the unique, long-period eclipsing binary star Epsilon Aurigae. Its extended spectral energy distribution is consistent with our previously published cool (550 K) dust disk model. We also present an archival infrared spectral energy distribution of the side of the disk facing the bright F-type star in the binary, which is consistent with a warmer (1150 K) disk model. The lack of strong molecular emission features in the Herschel bands suggests that the disk has a low gas-to-dust ratio. The spectral energy distribution and Herschel images imply that the 250 GHz radio detection reported by Altenhoff et al. is likely contaminated by infrared-bright, extended background emission associated with a nearby nebular region and should be considered an upper limit to the true flux density of Epsilon Aur.

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Epsilon Aurigae is bright enough to be seen with the unaided eye even in the most light-polluted cities, and it is visible every fall, winter and spring. The change in brightness that this star undergoes is called an eclipse (a process of fading and coming back to its usual brightness).
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Probing a centuries-old mystery in the stars

Atop Mt. Wilson, an astronomer hopes to find the key to Epsilon Aurigae, which for nearly two centuries has baffled astronomers with its fluctuations of light every 27.1 years.
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Title: The International Epsilon Aurigae Campaign 2009-2011. A description of the campaign and early results to May 2010
Authors: Robin Leadbeater

In early 2009, immediately following the end of the WR140 periastron campaign (see these proceedings), I turned my telescope back to epsilon Aurigae in time for the start of the eclipse. As well as being an interesting object in its own right, the Pro-Am campaign being run on epsilon Aurigae during the current eclipse is a good example of how amateur spectroscopists can make a useful contribution. epsilon Aurigae is a naked eye magnitude 3 star and was first noted to be variable by Johan Frisch in 1821. It was subsequently found to be an eclipsing binary with a period of 27.1 years which undergoes an approximately 2 year long flat-bottomed eclipse with approximately 0.8 magnitude drop in V.

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This is a planetarium show trailer developed for the Citizen Sky project developed by the California Academies of Sciences Morrison Planetarium, directed by Ryan Wyatt. Higher resolution, and 5.1 surround sound versions are available at CitizenSky.org. Planetariums can request a full dome copy for airing before their regular feature presentations. It is released for your own use under the Creative Commons Attribution-Sharealike 3.0 Unported license.

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Title: Epsilon Aurigae in Total Eclipse, 2010 - Mid-eclipse report
Authors: Robert E. Stencel
(Version v2)

Epsilon Aurigae is a complicated binary star that undergoes optical eclipses every 27 years, including the present year. An update is given here on the array of photometric and spectroscopic observations underway, thanks to the eclipse observing campaign and its dedicated participants. In addition, breakthrough results have emerged from (1) infrared and ultraviolet spectral energy distribution observations, and (2) especially with interferometric imaging that revealed the long suspected dark disk in transit, plus (3) new optical spectra that are revealing substructure inside the disk itself. Implications of many of these observations is discussed, but as the eclipse data are still being collected, I anticipate that additional discoveries are still to come, throughout 2010, and beyond.

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Title: Epsilon Aurigae in Total Eclipse, 2010 - Mid-eclipse report
Authors: Robert E. Stencel

Epsilon Aurigae is a complicated binary star that undergoes optical eclipses every 27 years, including the present year. An update is given here on the array of photometric and spectroscopic observations underway, thanks to the eclipse observing campaign and its dedicated participants. In addition, breakthrough results have emerged from (1) infrared and ultraviolet spectral energy distribution observations, and (2) especially with interferometric imaging that revealed the long suspected dark disk in transit, plus (3) new optical spectra that are revealing substructure inside the disk itself. Implications of many of these observations is discussed, but as the eclipse data are still being collected, I anticipate that additional discoveries are still to come, throughout 2010, and beyond.

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