E. F. Milone, Department of Physics, University of Calgary, writes that the mean of five differential UBV observations of HR 1099 relative to HR 1101 on Feb. 22.1664 (heliocentric) UT gave Delta-V = +1.58, Delta-(B-V) = +0.328, Delta-(U-B) = +0.42. The observations were made with the Rothney Astrophysical Observatory's 40-cm reflector. B. W. Bopp and J. C. Talcott, Ritter Observatory, write that spectrograms obtained during Feb. 21-23 showed that the equivalent width of the H-alpha emission was ~ 2.0 A, some 2-3 times greater than during quiescent intervals. The emission was significantly broader than the 1-A instrumental resolution on Feb. 21. On Feb. 22 there was some suggestion of variations of ~ 30 percent in the H-alpha equivalent width on a timescale of ~ 20 min. R. Hobbs, Y. Kondo and W. Feibelman, Goddard Space Flight Center, report that observations (dispersion 40 A/mm) on Feb. 24.05, 26.05 and 28.06 UT showed the H and K lines to exhibit strong emission cores on each occasion. Preliminary calibration shows that the emission was about twice as strong on Feb. 24 as on Feb. 26 and 28. H-alpha was also in emission, but because of unoptimized exposure at that wavelength no possible variation could be established.
International Astronomical Union Circular
- Pub Date:
- March 1978