Dirk Terrell

1
Pro-Am Collaborations on Eclipsing Binary Star
Problems

• Dirk Terrell
• Southwest Research Institute
• terrell_at_boulder.swri.edu

2
Our Group

• 35 members spread around the globe and always
  looking for more
• Mix of visual, photoelectric and CCD observers
• http//binaries.boulder.swri.edu
• Email discussion list

3
What We Do

• Visual observers tie down periods of new
  discoveries.
• Photoelectric and CCD observers get high
  precision data for times of minimum and full
  light curves in UBVRCIC filters.
• Some spectroscopy, mainly on the 1.8m at DAO in
  Victoria but also on the 2.2m at La Silla.
• Full analysis of data with the Wilson-Devinney
  code and PHOEBE to get binary parameters.

4
Equipment

• Mainly telescopes in the 0.2m to 0.4m range but
  we frequently get data from the 1.0m at USNO-FS
  (Henden).
• Mix of eyeballs, CCDs and photometers including
  the Optec SSP-4 for J and H band work

5
Current Projects

• Followup on ROTSE, Hipparcos, and other
  discoveries.
• UBVRCIC survey of W UMa systems.
• Simultaneous photometric-spectroscopic analyses
  of 100 short-period EB systems that Rucinski and
  colleagues have observed spectroscopically.
• J and H photometry of bright stars, mainly
  standards and Miras, but a handful of EBs such
  as Algol, ? Aur, ? Lyr, 44 Boo, and l Tau.

Images courtesy of Mark Garlick
http//space-art.co.uk/
6
Results OW Gem
OW Gem F2 Ib-II (5.8 M?) G8 II (3.9 M?) Primary
itself was once a binary
7
Results TU Mus
TU Mus Early-type overcontact system O7.5 V (23.5
M?) O9.5 V (15.3 M?)
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Results DK CVn
DK CVn Like V361 Lyr?
2002
2003
RC Data
9
Acknowledgements

• AAS Small Research Grants Committee for grants
  to several of our members for equipment.
• AAVSO for the Optec SSP-4 photometers and
  organizational support, especially Aaron Price.