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A photometric study of the light variations of the triple system DG Leo
Multi-site and multi-year differential photometry of the triple star DGLeo reveals a complex frequency spectrum that can be modelled as thecombination of at least three δ Scuti type frequencies in therange 11.5-13 c/d (with semi-amplitudes of 2-7 mmag) and a superimposedslow variability of larger amplitude. The period of the slow variationfits very well with half the orbital period of the inner spectroscopicbinary indicating the presence of ellipsoidal variations caused by thetidally deformed components in a close configuration. These findings,together with the results of a recent spectroscopic analysis (showingthat the system consists of a pair of mild Am stars and one A-typecomponent of normal solar composition), infer that DG Leo is anextremely interesting asteroseismic target. Identification of whichcomponent(s) of this multiple system is (or are) pulsating anddetermination of the excited pulsation modes will both contribute to amuch better understanding of the non-trivial link between multiplicity,chemical composition, rotation, and pulsation in the lower part of theclassical Cepheid instability strip.
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
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