M. Rodonò

  • Citations Per Year
Learn More
We lack a reliable scenario for the formation and evolution of stars and their planetary systems, involving key factors such as magnetic fields and turbulence. We present the case for a mission concept that will clarify these problems and give us a global view of the evolution of combined star and planetary systems. This will be achieved by simultaneously(More)
During the course of UBV photoelectric measurements made at the Catania Astrophysical Observatory we have observed an unusually intense optical flare on the nearby M dwarf G 102-21, the optical counterpart of a strongX-ray source recently detected by ROSAT. The amplitude of the magnitude increase (∆U ∼ 7.3 mag) and the total energy release in the UBV bands(More)
We present the results of an X-ray observation of the binary system AR Lacertae (HD 210334) obtained with the Low and Medium Energy Concentrator Spectrometers (LECS & MECS) and with the Phoswich Detector System (PDS) on board the Beppo-SAX satellite. Two flare episodes with comparable peak luminosities were detected, one in each of the two runs into which(More)
We present multifrequency VLA and VLBA observations at 8.4 GHz of the RS CVn system AR Lac, that were performed in autumn 1997 simultaneously with X-ray observations obtained from Rodonò et al. (1999). Our VLBA data indicate a resolved source with dimension close to the system separation, while the study of the flux density curve evidences a small amplitude(More)
We discuss the main characteristics of the orbital period modulation in close binaries with late-type components. We focus on the various physical scenarios proposed to explain this phenomenon and, in particular, Hall’s (1989) suggestion that it may be connected with magnetic activity. Starting from the work of Applegate (1992) and Lanza et al. (1998a), we(More)
We present Doppler Images of the RS CVn binary system HR 1099 (V711 Tau) from spectra taken in two different sites, KPNO and MSO, during the MUSICOS 1998 campaign. Contemporaneous APT photometry is used to constrain the Doppler Images. The resulting maximum entropy reconstructions based on the leastsquares deconvolved profiles, derived from ∼2000(More)
We present an analysis of a sequence of light curves of the RS CVn-type binary II Pegasi extending from 1974 to 1998. The distribution of the spotted area versus longitude is derived by Maximum Entropy and Tikhonov regularized maps, assuming a constant spot temperature (Lanza et al. 1998a). The spot pattern on the active K2 IV star can be subdivided into a(More)
The epochs of the primary and secondary minima of AR Lac between 1900 and 1989 are analysed with two nonparametric methods of searching for periodicity in a weighted time point series. An analytical model for transforming the O−C data of eclipsing binaries into the period domain is presented and is applied to AR Lac. The abrupt period changes of AR Lac(More)
Spectroscopic observations of the bright RS CVntype system V 711 Tau = HR 1099 (K1 IV + G5 V) were obtained by IUE during the same period of a Multi-Site Continuous Spectroscopy (MUSICOS) campaign between 12–18 December 1992 (Huang et al. 1995). We report on the results of a “Doppler Imaging” analysis of the Mg II h line. Broad, variable and extended wings(More)