Eyjafjallajokull may sound like a word lifted from Finnegans Wake (a novel by James Joyce), but the Icelandic volcano has grabbed worldwide attention by producing a dense ash cloud that threatens jet aviation over much of northern Europe again this week. In this third blog exploration of the implication of direct detection of the disk in epsilon Aurigae, via interferometric imaging, I want to explore with you how terrestrial volcanic ash provides some analogies with the dusty material that scientists believe make up "debris disks" seen around a surprising percentage of normal stars. Read more
Dr. Bob and I are taking turns explaining the implications of the recent Nature paper. In the first post, Dr. Bob discussed two very important questions: "How big?" and How massive?" In this post, I'm going to cover another big-picture topic: the orientation of the disk.
I'll start with what we thought happened. Most of the literature drew the disk as something that more-or-less bisected the F-star, following Kemp's 1986 drawing (note, a similar drawing was also published in the 1985 epsilon Aurigae conference proceedings):
We've just posted a new tool on the Citizen Sky web site. Created by colleagues from Adler Planetarium and Astronomy Museum, the epsilon Aurigae Simulator allows the user to manipulate various parameters of the system and view the resulting lightcurve.
Brian has written a tutorial, which offers a quick introduction to the simulator. This is a great chance to read up on all of the recent results on eps Aur and use them to model your own version of the system. Have fun!
The set of images published in Nature on April 8th 2010 represent only a few nights of observing, mainly during ingress phases of this eclipse. Brian and I will, in tag team form, blog about a number of facets about the observation and its implication, and provide a sense of what's next in this process.
First, this direct detection of the disk is a wonderful demonstration of the scientific method: long theorized to be there, and at long last it is observationally confirmed.
You might ask: The disk must be large, but how large? And how massive? How far is the companion from Epsilon Aurigae?
How large? It's big - nearly reaching the orbit of Jupiter around the Sun if we moved it into our solar system, and as thick as earth's orbit in the vertical dimension. This dimensional estimate is dependent on distance assumptions, but we'll come back to that.Read more
We will be hosting a chat this Friday, April 9 starting at 16 UT (Noon Eastern, 11:00 AM Central, 10:00 AM Mountain, and 9:00 AM Pacific). This chat is a little different than our previous chats because we have partnered up with Astronomers Without Borders and their Global Astronomy Month project.
This chat will be much like our other "Beginners' Chats" in the past in that the goal will be to answer questions about Citizen Sky, Astronomers without Borders, epsilon Aurigae, and/or astronomy in general. The tone will be tailored to new participants in the project so this is a great chance to find out more about the project without feeling overwhelmed by the scale of the project. Also, Rebecca Turner, the project manager, will be on hand to answer general questions about Citizen Sky.Read more
This weeks' big announcement can now be made, the paper that Dr. Stencel alluded to
is now published (in the April 8 issue of Nature). If you subscribe to Nature, you can access the article here. For those of you who do not have a subscription to Nature, I'll post up the article as submitted to a website and include the link later this week. Until then, say hello to the disk:Read more
We are pleased to announce that images of the disk occulting the F star were obtained interferometrically during ingress (autumn 2009). Details of this will appear in this week's issue of NATURE journal, April 8th edition. Watch this space later in the week for more discussion about those pictures and what they tell us.
It's been a long road to get those images that confirm the disk explanation for the epsilon Aurigae eclipses. Previous blogs and many online sources help explain the method, but its application to epsilon Aurigae has only really become practical this decade with the improvements in "closure phase" imaging made possible with the NSF-sponsored Michigan IR Combiner (MIRC) instrument, at the CHARA array atop Mt. Wilson.Read more
A new, open-source data visualization and analysis tool called VStar is now ready for download. It is the product of a Citizen Sky programming team led by David Benn - VStar Software Development Team. We are very proud of VStar and thank the team for the many, many hours of hard work that have gone into creating this tool.