Blog / Monthly archive / March 2010
March 2010
Literature Review: A Heated Disk
I have just posted a literature review to the forums in which I discuss the heated disk model for the eps Aur system.
So far this makes five mini-discussions on eps Aur literature. I've barely scratched the surface so if there is something you are wondering about, let me know and I'll see if I can find an article discussing it!Read more
Development #1: The complete Spectral Energy Distribution (SED)!
3/23/2010-- As reported by Hoard, Howell and Stencel...
(2010 to appear in the Astrophysical Journal), data have become available that span a wide spectral range, from the far-ultraviolet, through the visible range and out into the far-infrared. Because of calibration efforts, it has proven possible to combine these well calibrated data into a complete and self-consistent picture of the sources of light in epsilon Aurigae. Key to understanding this result is that interlocking requirements of distance and other constraints on F star diameter drive us to these self-consistent conclusions.
The full paper is available, free, at website:
http://arxiv.org/pdf/1003.3694v1
IRTF: Data Reduction
How the data is reduced.
In short, we use a program developed specifically for reducing spectra from SPEX called SPEXTOOL. It is written in a commonly used programming language for Astronomers called IDL. I'm going to skip over a lot of the details, but in SPEXTOOL there are basically two steps:
- Construct Calibration Frames (for wavelength calibration, flat-field subtraction).
- Extract the spectral orders.
As you may recall from my last post, we took a series of calibration frames called arcs. I've extracted a section of the image in my last post as a reminder:
Read more
Report from the Interferometry meeting
Bounce during totality: have you noticed that epsilon is a bit brighter this month compared to last? Totality is with us, but the Out of Eclipse variations continue. We anticipate a significant brightening starting next month as the central opening in the disk begins crossing in front of the F star...
It's been a pleasure to attend the 5 year science review meeting of the CHARA collaboration (http://www.chara.gsu.edu/CHARA/ ) an amazing group that runs the interferometer atop Mt. Wilson, CA. This 300 meter baseline telescope is capable of delivering milli-arcsecond imaging that has made the details of the epsilon Aur eclipse much more obvious, as has been reported in recent popular articles in Sky & Telescope, Astronomy and Astronomy Now. Read more
CS in the 2011 Science Olympiad Coach's Guide
(Update: The updated CDROM is now ready.) Donna Young, the Science Olympiad astronomy event coordinator, has completed a Teacher's Guide for the Citizen Sky project which will be on the next version of the Science Olympiad coach's CDROM. Next year's CD will be available in late summer or fall, but we have place the teacher's guide online right now. You can download it here.Read more
IRTF: What the data looks like
As I have mentioned before, the instrument we used at IRTF is called SPEX. It is a medium resolution spectrograph. Specifically, it's a cross-dispersing spectrograph. What does this mean? Well, instead of dispersing light like a prism where the colors are all in one line, SPEX breaks the spectrally dispersed light into several orders that are displayed along side each other. I've included a copy of a figure I made for a previous presentation that includes SPEX data in LXD1.9 mode to give you an idea about the dispersion:
