Irregular light-fluctuations of UX Monocerotis.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Irregular light-fluctuations of UX Monocerotis. Wood, Frank Bradshaw Abstract The eclipsing system, UX Monocerotis, has been observed photoelectrically in two colors. The observations were made with Photometer C' and the 36-inch reflector of the Steward Observatory. The effective wave lengths were 5200 A and 4250 A. While the light curve is not yet completely covered, the following preliminary results may be announced. Primary minimum has a depth of about 0.95 mag. in the yellow and 1.3 mag. in the blue. Secondary minimum has a depth of approximately 0.15 mag. in both colors and seems centrally located on the present incomplete curve. Irregular light-fluctuations were found on many nights on which the system was observed; the maximum size of these fluctuations was of the order of 0.2 mag. Observations of a check star and of other eclipsing systems on the same nights, indicate clearly that these are not caused by fluctuations in the photometer or in the sky. In the case of the more rapid fluctuations, it usually takes an hour or two for the system to complete the fluctuation and to regain its original brightness. The nature of the light change is ordinarily similar in both colors, but the magnitude of the variation in the blue is usually appreciably greater than that in the yellow. No evidence of periodicity or of other regularities of these fluctuations is shown by the observations available at present. A slower type of light variation is indicated by the observations of the same part of the light curve taken six or more days apart. Such observations sometimes yield congruous results, but sometimes differ by amounts ranging to more than 0.1 mag. Magnitude differences between the comparison and check stars on these nights show no such variation. Again the variation is usually greater in the blue than in the yellow. While it seems premature to attempt an explanation of these fluctuations, it may be pertinent to point out that the spectral region outlined by the yellow filter contains the HP line; the blue region contains H7, H~, HE, and the lines of Ca II. In his spectrographic study of the system, Struve2 found remarkable changes in the intensities of these lines. I.A. J. 54, 182, i86, 1949. 2.Ap. J. io6, 255, 1947. Steward Observatory, University of Arizona, Tucson, Ariz. Publication: The Astronomical Journal Pub Date: October 1950 DOI: 10.1086/106408 Bibcode: 1950AJ.....55..186W full text sources ADS | data products SIMBAD (1)