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JAAVSO 2008 the Journal of the American Association of Variable Star Observers Volume 36 Number 1 JAAVSO 2008 The Journal of the American Association of Variable Star Observers Detection of the First Observed Outburst of DW Cancri Photometric light curve from all AAVSO V filter observations of DW Cnc between 2006 December 24 and 2007 February 04. Also in this issue... • Discovery and Observations of the Optical Afterglow of GRB 071010B • On the Connection Between CWA and RVA Stars • Studying Variable Stars Discovered Through Exoplanet-Transit Surveys 49 Bay State Road Cambridge, MA 02138 Complete table of contents inside... U. S. A. The Journal of the American Association of Variable Star Observers Editor Associate Editor Charles A. Whitney Elizabeth O. Waagen Harvard-Smithsonian Center for Astrophysics Assistant Editor 60 Garden Street Matthew Templeton Cambridge, MA 02138 Production Editor Michael Saladyga Editorial Board Priscilla J. Benson John R. Percy Wellesley College University of Toronto Wellesley, Massachusetts Toronto, Ontario, Canada Douglas S. Hall David B. Williams Vanderbilt University Indianapolis, Indiana Nashville, Tennessee Thomas R. Williams Houston, Texas The Council of the American Association of Variable Star Observers 2007–2008 Director Arne A. Henden President Paula Szkody Past President David B. Williams 1st Vice President Jaime Ruben Garcia 2nd Vice President Michael A. Simonsen Secretary Gary Walker Treasurer David A. Hurdis Clerk Arne A. Henden Councilors Barry B. Beaman Arlo U. Landolt James Bedient Karen Jean Meech Gary Billings Christopher Watson Pamela Gay Douglas L. Welch ISSN 0271-9053 JAAVSO The Journal of The American Association of Variable Star Observers Volume 36 Number 1 2008 49 Bay State Road Cambridge, MA 02138 ISSN 0271-9053 U. S. A. The Journal of the American Association of Variable Star Observers is a refereed scientific journal published by the American Association of Variable Star Observers, 49 Bay State Road, Cambridge, Massachusetts 02138, USA. The Journal is made available to all AAVSO members and subscribers. In order to speed the dissemination of scientific results, selected papers that have been refereed and accepted for publication in the Journal will be posted on the internet at the eJAAVSO website as soon as they have been typeset and edited. These electronic representations of the JAAVSO articles are automatically indexed and included in the NASA Astrophysics Data System (ADS). eJAAVSO papers may be referenced as J. Amer. Assoc. Var. Star Obs., in press, until they appear in the concatonated electronic issue of JAAVSO. The Journal cannot supply reprints of papers. Page Charges Unsolicited papers by non-Members will be assessed a charge of $15 per page. Instructions for Submissions The Journal welcomes papers from all persons concerned with the study of variable stars and topics specifically related to variability. All manuscripts should be written in a style designed to provide clear expositions of the topic. Contributors are strongly encouraged to submit digitized text in LATEX+POSTSCRIPT, MS WORD, or plain-text format. Manuscripts may be mailed electronically to journal@ aavso.org or submitted by postal mail to JAAVSO, 49 Bay State Road, Cambridge, MA 02138, USA. Manuscripts must be submitted according to the following guidelines, or they will be returned to the author for correction: Manuscripts must be: 1) original, unpublished material; 2) written in English; 3) accompanied by an abstract of no more than 100 words. 4) not more than 2,500-3,000 words in length (10–12 pages double-spaced). Figures for publication must: 1) be camera-ready or in a high-contrast, high-resolution, standard digitized image format; 2) have all coordinates labeled with division marks on all four sides; 3) be accompanied by a caption that clearly explains all symbols and significance, so that the reader can understand the figure without reference to the text. Maximum published figure space is 4.5” by 7”. When submitting original figures, be sure to allow for reduction in size by making all symbols and letters sufficiently large. Photographs and halftone images will be considered for publication if they directly illustrate the text. Tables should be: 1) provided separate from the main body of the text; 2) numbered sequentially and referred to by Arabic number in the text, e.g., Table 1. References: 1) References should relate directly to the text. 2) References should be keyed into the text with the author’s last name and the year of publication, e.g., (Smith 1974; Jones 1974) or Smith (1974) and Jones (1974). 3) In the case of three or more joint authors, the text reference should be written as follows: (Smith et al. 1976). 4) All references must be listed at the end of the text in alphabetical order by the author’s last name and the year of publication, according to the following format: Brown, J., and Green, E. B. 1974, Astrophys. J., 200, 765. Thomas, K. 1982, Phys. Report, 33, 96. 5) Abbreviations used in references should be based on recent issues of the Journal or the listing provided at the beginning of Astronomy and Astrophysics Abstracts (Springer-Verlag). Miscellaneous: 1) Equations should be written on a separate line and given a sequential Arabic number in parentheses near the right-hand margin. Equations should be referred to in the text as, e.g., equation (1). 2) Magnitude will be assumed to be visual unless otherwise specified. 3) Manuscripts may be submitted to referees for review without obligation of publication. © 2008 The American Association of Variable Star Observers. All rights reserved. Journal of the American Association of Variable Star Observers Volume 36, Number 1, 2008 Period Change in the Semiregular Variable RU Vulpeculae Matthew Templeton, Lee Anne Willson, Grant Foster 1 How to Understand the Light Curves of Symbiotic Stars Augustin Skopal 9 On the Connection Between CWA and RVA Stars Patrick Wils, Sebastián A. Otero 29 Studying Variable Stars Discovered Through Exoplanet-Transit Surveys: A “Research Opportunity Program” Project John R. Percy, Rahul Chandra, Mario Napoleone 44 Discovery and Observations of the Optical Afterglow of GRB 071010B Arto Oksanen, Matthew Templeton, Arne A. Henden, David Alexander Kann 53 Detection of the First Observed Outburst of DW Cancri Tim Crawford, David Boyd, Carlo Gualdoni, Thomas Gomez, Walter MacDonald II, Arto Oksanen 60 Analysis of BVI Photometry of the Eclipsing Binary EV Lyrae Jerry D. Horne 68 Combining Visual and Photoelectric Observations of Semiregular Red Variables Terry T. Moon, Sebastián A. Otero, Laszlo L. Kiss 77 The Exciting Star of the Berkeley 59/Cepheus OB4 Complex and Other Chance Variable Star Discoveries Daniel J. Majaess, David G. Turner, David J. Lane, Kathleen E. Moncrieff 90 Infrared Passbands for Precise Photometry of Variable Stars by Amateur and Professional Astronomers Eugene F. Milone, Andrew T. Young 110 Adventures in J- and H-Band Photometry of Evolved Stars Aaron J. Bradley, Robert E. Stencel 127 Abstracts of Papers and Posters Presented at the 96th Spring Meeting of the AAVSO, June 26–July 3, 2007, Calgary, Alberta, Canada Period Change Behavior of the Algol-Type Eclipsing Binary LS Persei Gary Billings 139 Long-Term Photometric Variability of 13 Bright Pulsating Red Giants John R. Percy, Cristina O. Nasui, Gregory W. Henry 139 A Multicolor Photometric and Fourier Study of New Field RR Lyrae Variables Michael Koppelman, Richard Huziak, Walter Cooney, Vance Petriew 140 Research Breakthroughs From Pro-Am Collaborations David G. Turner 140 Table of Contents continued on next page Slowly Pulsating B Stars: A Challenge for Photometrists Robert J. Dukes Jr., Laney Mills, Melissa Sims 141 One Little Telescope, So Many Stars Jaymie Matthews 141 Suspected Variables in AAVSO Star Fields Richard Huziak 142 The AAVSO Standard Star Database (VSD) and the Variable Star Plotter (VSP) Vance Petriew, Michael Koppelman 143 Automated Variable Star Observing and Photometric Processing at the Abbey Ridge Observatory (ARO) David J. Lane 143 Templeton et al., JAAVSO Volume 36, 2008 Period Change in the Semiregular Variable RU Vulpeculae Matthew Templeton AAVSO, 49 Bay State Road, Cambridge, MA 0238 Lee Anne Willson Department of Physics and Astronomy, Iowa State University, Ames, IA 5004 Grant Foster Island Data Corporation, 2386 Faraday Ave., Suite 280, Carlsbad, CA 92008 and AAVSO, 49 Bay State Road, Cambridge, MA 0238 Received September 4, 2007; revised November 30, 2007, accepted January 0, 2008 Abstract The well-observed semiregular variable RU Vulpeculae has undergone a substantial change in period over the past fifty-five years. The discovery period of ~155 days has undergone a continuous change to its current value of 108 days. The amplitude and stability of the light curve have changed as well; the pulsations are much less regular and have a lower amplitude now than at the time of RU Vul’s discovery and classification. The character of the period change is quantitatively similar to that of the well-studied Mira variable T Ursae Minoris, and we argue that RU Vul may be a semiregular analog of Mira variables undergoing dramatic period changes. We place RU Vul in the context of other AGB stars exhibiting similar behavior, and discuss possible explanations for its period change. 1. Introduction The Templeton et al. (2005) study of 547 well-observed Mira variables found that about 1.5 percent of Mira stars exhibit large, easily detectable changes in pulsation period. One possible explanation for these changes is that they are due to thermal pulses, which are rapid, helium-shell burning events predicted to occur in asymptotic giant branch (AGB) stars. These pulses and their aftereffects last for a few thousand years, and their occurrence is confirmed observationally by the presence of the short-lived isotope technetium in the spectra of many AGB stars. The energy generated in these pulses would act to change the equilibrium structure of the star, resulting in a substantial change in pulsation period detectable on observable timescales.
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