Epsilon Aurigae Campaign 2009

This web site was created by Jeffrey L. Hopkins and Dr. Robert E. Stencel in May of 2006. It is acting as the International Epsilon Aurigae Campaign Web site for the 2009 - 2011 eclipse of the star system. The periodic Campaign Newsletters are edited by Jeffrey Hopkins with Dr. Robert Stencel as Coeditor. The site is hosted and maintained by the Hopkins Phoenix Observatory.

The Eclipse is over!

Final Newsletter #24 Now Available!

Complete UBVRcIcJH Band Photometric Analysis of 2009-2011 Eclipse

Images of all Analysis Plots



American Astronomical Society Meeting Summer 2013

Giants of Eclipse Meeting: Monterey, California 28 July - 2 August 2013

This meeting welcomes observers, analysts, theorists, spectroscopists and photometrists. It will examine, probe, debate and perhaps solve some of the mysteries which the many series of detailed high-quality data reveal about these and similar systems, and will seek to define the next generation of observational programs within an era of large-scale surveys.

Eclipsing binaries as astrophysical calibrators
Stellar chromospheres and coronae Imaging, interferometry; magnetism, spectropolarimetry
Modelling, binary evolution and mergers, with special emphasis on
Zeta Aurigae binaries and atmospheric eclipses
Epsilon Aurigae: new observations, interpretations

Workshop sessions each afternoon will also feature special-interest discussions of selected phenomena, data, methods, instrumentation, etc.

Epsilon Aurigae Star System

The epsilon Aurigae system is among the most interesting eclipsing star systems. It has puzzled astronomers for nearly 200 years. It is a bright star (3rd magnitude) located about 3 degrees southwest of Capella and eclipses once every 27.1 years. It is at the vertex of a triangular group of stars known as "The Kids". Zeta Aurigae, another interesting long-period eclipsing binary, makes up one of the other two stars.

What makes this star system so intriguing is not just its long period but the length of its eclipse, what happens during the eclipse and what happens out-of-eclipse. The eclipse lasts nearly two years which with the 27.1 year period means the eclipsing body must be gigantic. There have been no satisfactory explanations for this. To make matters even more interesting, there seems to be a mid-eclipse brightening. How can this be? One explanation, according to James Kemp, is that the eclipsing body is a giant cloud of gas enclosing two small stars in orbit around each other. These stars sweep out an area in the middle. It would be a bit like a giant donut. This donut must be tilted such that as it eclipses the primary star, the system's total light decreases and the "donut-hole" allows some of the primary star's light to sneak through at mid-eclipse.

To try to unravel this system's mystery, a concentrated effort was undertaken during the 1982-1984 eclipse. Hundreds of astronomers, amateurs and professionals, from around the world, observed the eclipse. Space born satellites observed in the ultraviolet and infrared. Ground based observations were photometric, spectroscopic, and polarmetric. Photometric observations were made with UBV filters, narrow band filters, and at wavelengths into the far infrared. Despite the concentrated efforts, epsilon Aurigae remains a mystery. The secondary eclipse was due to occur around 1996/1997. Detection of the secondary eclipse light variation is on the order of the out-of-eclipse variations. This makes separating the two periods very difficult. An effort is underway to try to predict the pulsations through continuing observations. If these pulsations can be predicted, observation of the secondary eclipse may be possible.

For those astronomers (both professional and amateur) interested, while the next eclipse will not start until August of 2009, now will be a good time to join a campaign and get prepared. Also, more out-of-eclipse observations are needed before the next eclipse.

Epsilon Aurigae is anything but quiet out-of-eclipse. A seasonal 68 day period that seems to be gradually increasing in amplitude is being seen. There are many surprised yet to be found with this interesting star system. Surely, by the end of the next eclipse, astronomy will have unraveled the mystery of epsilon Aurigae.

The History and Evolution of the Disk theory for Epsilon Aurigae



* Basic System Data

Star Chart
Star Information

* Campaign Members

How to Join
How to Contribute
Member List

* 2009 - 2011 Campaign

Newsletter #1
Newsletter #2

Newsletter #3

Newsletter #4
Newsletter #5
Newsletter #6
Newsletter #7

Newsletter #8
Newsletter #9
Newsletter #10
Newsletter #11
Newsletter #12
Newsletter #13

Newsletter #14

Newsletter #15
Newsletter #16
Newsletter #17
Newsletter #18

Newsletter #19
Newsletter #20
Newsletter #21
Newsletter #22
Newsletter #23
Newsletter #24 Final


Newsletter Index

* Photometry

Photometry Data
How To

* Spectroscopy

High Resolution
Low Resolution
How To
Line Profiles

* Polarimetry

Basics - TBD
How To - TBD
Data - TBD

* References

1982 - 1984 Campaign

NASA Reference 2384
(.pdf 4.9 MB)

Current References

IBVS Articles

* Similar Star Systems

BM Orionis
Zeta Aurigae

EE Cephei
VV Cephei

* Links

Epsilon Aurigae

A Mysterious Star System

Sold Out!
Watch for second edition

AAS Poster Paper January 2010
Epsilon Aurigae
Two Year Totality Transpiring

Summary of 1982 - 1984 Eclipse

Current 2009 Eclipse Predictions

Sign up for the latest on epsilon Aurigae
Epsilon Aurigae News List

2009/11 Composite Photometric Plots
UB, V, RI & JH Bands as of 08 August 2011

Pre-Ingress. Ingress, Totality and Egress

V Band Composite Plot

B and U Band Composite Plots

R and I Band Composite Plots

J and H Band Composite Plots

All UBVRIJH Data Archive


August 2009 Workshops
Created and Presented
Jeffrey L. Hopkins
Hopkins Phoenix Observatory

DSLR Photometry
(ppt 4 MB)

DSLR Photometry
(pdf 1.4 MB)

(ppt 8.9 MB)

pdf 2.5 MB)

Recent (04 February 2011)
hydrogen alpha Spectra
by Jose Ribeiro

Astronomical Time

It is very important that anyone who makes astronomical observations understands astronomical time

Images from the 2010
SAS Symposium
Big Bear, California
11-13 May 2010



The Very Long Mystery of Epsilon Aurigae
Robert E. Stencel
Sky & Telescope, May 2009 Page 58

SAS 2009 Papers

Epsilon Aurigae, 2009: The eclipse begins
observing campaign status (.pdf)

Epsilon Aurigae
Hydrogen Alpha Emission Line Variation
The Horn Dance (.pdf

New! SAS 2010 Papers

Epsilon Aurigae Eclipse 2009 - Ingress (.pdf)

Epsilon Aurigae Eclipse 2009 - Ingress (.ppt)



Small Telescope
Astronomical Spectroscopy

240 pages SC full color with CD ROM



Mount Wilson/CHARA
Trip 21-23 September 2010

Mount Hopkins MMT
Trip 20-23 December 2010

217 AAS Meeting Report
21 January 2011

Epsilon Aurigae Star System
Schematic Diagram

Created: 30 May 2006
Modified : 26 November2012

Web page background artwork by D. Egge (c)1985, with permission

Webmaster: HPO SOFT