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We present the results from a photometric monitoring program of 15 open cluster stars and one weak-lined T Tauri star during late 1993/early 1994. Several show rotators which are members of the Alpha Persei, Pleiades, and Hyades open clusters have been monitored and period estimates derived. Using all available Pleiades stars with photometric periods together with current X-ray flux measurements, we illustrate the X-ray activity/rotation relation among Pleiades late-G/K dwarfs. The data show a clear break in the rotation-activity relation around P approximately 6-7 days -- in general accordance with previous results using more heterogeneous samples of G/K stars.

The star, Altair (A7 IV-V), is clearly shown to have Lyman-alpha emission of chromospheric origin, while no evidence is found for the Mg II emission reported in previous investigations. We present non-Local Thermodymanic Equilibrium (non-LTE) semiempirical models incorporating partial redistribution of the chromosphere of Altair that reproduce the observed Lyman-alpha emission and the Mg II resonance absorption at 2800 A. We unambiguously establihed that chromospheres exist at spectral types as early as A7 on the main sequence, and we also demonstrate that it very unlikely that the observed emission originates in a corotating expanding wind. This result represents a new challenge for chromospheric heating theories. It may indicate that both differential rotation and convection layers, at least near the equator, exist in this fast rotating (v sin i = 220 km/s) star.

We present the results of the first three years of a single dish radio monitoring of HR 1099 we are carrying out using the the 32m radiotelescope at the Noto VLBI station of the Istituto di Radioastronomia of the Italian Consiglio Nazionale delle Ricerche (C.N.R.).These data, together with other observations available from literature, constitute a database which shed light on the radio emission from this system.HR 1099 tends to undergo extended periods of strong activity, interrupted by periods of low flux density level, as can be seen from the radio behaviour on a timescale of several months. The switching between flaring and quiescent periods is not random and, at the moment, it is not possible to associate a characteristic duration to each phase.

Sartre rejects the Freudian unconscious and views consciousness as translucent. How then can he claim that we deceive ourselves? It would seem that any lie to ourselves would have to disintegrate beneath the clear light of awareness and to degenerate into cynicism.' But I think that Sartre is right; we do deceive ourselves, and I believe that he has presented a generally viable description of how self-deception occurs. The text in question is the chapter "Bad Faith" in part one of Being and Nothingness.1 Two things should be noted about the placing of this chapter in the context of the book. First, logically, it depends on the chapter before it, "The Origin of Negation," and second its full significance is not developed until the section "Existential Psychoanalysis" in chapter two of part four. Textually, the significance of this claim reduces to the fact that Being and Nothingness is not a collection of essays, but a book with a unified structure. This fact is seldom fully appreciated. There is a specific logic to the book as a whole; it proceeds from the abstract to the concrete in such a way that the concrete is more than an instance of the abstract. True, the work is a phenomenological ontology, and, as such, it aims at descriptions rather than syllogistic deductions. But the descriptions work within a very tightly controlled methodology. To be precise, Sartre, in Being and Nothingness, never says more than is needed to make the specific point in question. This logic is so geared that the phenomenological descriptions pivots about the chapter on the body in part three, chapter two. It is there that we discover that the conscious

This review presents a summary of observed photospheric phenomena on RS CVn stars: the amplitude, shape, evolution and migration rate of the photometric wave in relation to the rotational and orbital motion.The main points considered are: 1) the activity level (maximum amplitude, short and long timescale variability) versus rotation period; 2) the activity cycles as inferred from changes in the wave migration rate and direction and from the variation of its amplitude; 3) the detection of differential rotation; 4) the connection between the orbital period variation and activity.

We present a relatively completeV-band light curve of SZ Psc for 1978 and a partial light curve for 1977. From the 1978 light curve we derive a new time of primary minimum, JD⊙2443823.674±0.001, and a Russell-model solution,i=75°.8±0°.1,r h =0.096±0.003,r c =0.351±0.001, andL h =0.253±0.002. The hotter component of this system is a F5-8 main-sequence star, the cooler component a K3-4 star well above the main sequence. The system is detached with the larger component filling only 82% of its Roche lobe. The distortion wave in this RS CVn-type binary seems not to migrate regularly as do those in many other such systems, but rather seems to change phase and amplitude more erratically. Between 1977 and 1978 its phase stayed practically constant while its amplitude decreased by a factor of three. We discuss the implications of this behavior for the spot model of RS CVn-type activity. We find that the traditional comparison star for SZ Psc, HD 219018, is very likely a constant star contrary to a recent suggestion that it is variable. Its brightness and colors,V=7.705, (B-V)=0.628, and (V-I) c =0.688, are those of a G2V star.

We report on the first successful coordinated observations of stellar flares carried out on March 28, 1984 simultaneously over a wide range of wavelengths, from UV to microwaves, using the IUE satellite, three ESO telescopes at La Silla (Chile) and the VLA at Socorro (NM, USA).

In spite of its importance as cooling mechanism of the chromosphere of late type stars, the hydrogen Lyman-alpha line has been neglected in most IUE programmes The high geocoronal background and the saturation often seen in the stellar emission peak are the major problems that prevent accurate determination of the Lyman alpha flux. We have developed a technique that allows us to overcome both of these problems by fitting an ellipsoidal surface to the geocoronal background and gaussian profiles to the stellar signal. Results on a limited sample of stars are presented.

We present a complete set of yearly seasonal light curves (LC) of RS CVn obtained from 1963 to 1982 at Catania Observatory, integrated with two LCs obtained by Ludington (1978) in 1975 and 1976. This unique observation set vividly shows (Figure l) the migrating outside of eclipse “photometric wave” (PW), which was first evidenced by Catalano and Rodonò (1967) and it is now considered the distinctive photometric feature of RS CVn binaries as well as of other spotted stars. By attributing the PW to surface inhomogeneities, or spots, whose visibility is modulated by the spotted star rotation, the present PW migration toward decreasing orbital phases indicates that the angular rotation of the KOIV spotted component is slightly lower than the orbital one. An inspection of Figure 1 readly shows that the almost sinusoidal PW has been fairly stable from 1963 up to 1981, when a double-peaked wave, still present in the 1982 LC, developed. Most probably the “unusual” 1949 LC by Keller and Limber (1951) and the 1976 one by Ludington (1978) were obtained at a similar activity phase.

L'analyse des valeurs chez Sartre a travers l' " Etre et le Neant ", " Reflexions sur la question juive ", " Saint Genet, comedien et martyr ", " Critique de la raison dialectique "

The behaviour of the available light curves of Jupiter and Saturn satellites is shown to change steadily from inner to outer satellites.The change in reflectivity of satellites with orbital motion could be explained assuming that dark meteoroidal material accumulates on a given portion of the satellite's surface, which was once mainly covered with ice or snow. The preferential impact location on the satellite's surface could be a consequence of the perturbing action of the planet on the motion of interplanetary material.

The photoelectric observations of the close binary RS CVn carried out at Catania Observatory from 1963 to 1973 are presented. A new period of 9.48 years for the retrograde migration of the wave-like distortion on the light-curve has been determined. The wave amplitude is found to undergo cyclic changes with a period of about 4.74 years.Possible correlation between the wave amplitude and the inclination of the rotational axis and the spectral type of the spotted component for several RS CVn and BY Dra binaries is investigated.

A lightcurve of Vesta, obtained on four nights between June 23 and 30 June 1978 during the coordinated campaign for the determination of the rotation period, is presented. The observations were performed at the 91-cm telescope of the Catania Observatory employing UBV filters and a photon counting photometer. The V lightcurve apparently shows a single maximum, suggesting that the 5h20m29s.2 period is the correct one. Features are evident near the maximum and the minimum closely resembling those of Johnson's lightcurve of 22 December 1950 and Taylor's of January 21, 1973. The amplitude in V light is 0m.105 and small variations are also found in the color indices. The largest color variation is for the U-V with Δm = 0.m.05, which is slightly larger than the value 0m.02 found by T. Gehrels [Astron. J. 72, 929 (1967)]. The maximum and minimum values occur at the same phase with respect to the maximum V light as found by Gehrels, i.e., Vesta appears bluer near 0p.25 and redder near 0p.7. Corrections with the solar phase angle were made using the coefficients given by Gehrels for the B-V and U-V while a new value of 0.036 mag/deg was assumed for the V observations. The available amplitudes of Vesta's lightcurve were analyzed with respect to the longitude position and the solar phase angle.

Results of a worldwide photometric investigation of the asteroid 324 Bamberga conducted from September to November 1978 are presented. The full-cycle light curve obtained from observations at Torino, Graz, Catania and Table Mountain observatories shows two maxima and two minima with a maximum amplitude of 0.075 magnitudes from which rotation period of 29.42 plus or minus 0.01 hours is derived. Linear least squares solution of the phase relation results in a phase coefficient of 0.034 plus or minus 0.001 mag/deg, a mean V magnitude of 7.20 and a zero-phase absolute V magnitude of 7.17 plus or minus 0.01. The color indices obtained (0.69 for B-V and 0.36 for U-B) are in agreement with the C taxonomic type assigned to the asteroid. The unusual length of the period of 324 Bamberga relative to that of other asteroids of diameter greater than 200 km is pointed out.

Lightcurves of asteroid 44 Nysa obtained during 20 nights in 1979 as part of a global compaign are presented. The synodic period was 6 hours and 25.3 minutes. The phase coefficient of the primary maximum was 0.026 mag/deg and the absolute V magnitude 7.05. The phase function is linear from 2 to 25 deg, no opposition effect is present.

From photoelectric observations of V 337 Aql a new solution is carried out. Transit at primary eclipse in disagreement with the Wright-Dugan results is found. Both Russell-Merrill and Kitamura methods of light curve solution are used. The slight period variation and the distortions of the light curve would support the idea that a mass exchange could be in act.

Results of the correlation between the air temperature recorded at Catania in the period 1817–1970 and the sunspot number R, are reported. The temperature and the sunspot number, both averaged over the 11 year solar cycle, give a coefficient r = 0.5 for a linear correlation. The higher mean temperatures are associated with the more active solar cycles and the lower mean temperatures with cycles of lower mean activity. No reliable correlations were found in time scales of less than a solar cycle.

A long-term variation of the magnitude at mean opposition is shown to exist for Io and Titan. The variation of Io seems to be correlated with the orbital period of Jupiter, the maximum light occurring at perihelion.

Here we present a quatitative approach to the problem of the chromospheric emission and rotation in main sequence stars based on a consistent analysis of recent published data of stars from F8 to K5. This analysis has been performed using the following physical parameters:a) total power emission in the Call K line, Lk;b) stellar rotation period, Prot, from chromospheric emission variability;c) stellar ages from lithium abundance.

Short-term variations, typically with small amplitude (Δm < 0.1 mag.), time-scales of hours or near one day and in many cases correlated with the rotation period have been found to be commonplace among Be stars (see Harmanec and Pavlovski 1983 for review and papers). Radial and non-radial pulsation modes have been proposed to explain this variability. However, the light curves are often double-peaked, at first suggesting the stars may have large organized dipole magnetic fields and spots not unlike those in the Ap or Bp stars (Harmanec 1983). These rotationally modulated variations are not stable, and seem to vary in both amplitude and period in the sense that intervals with well defined light curves alternate with intervals when variations are absent. This phenomenon is very reminiscent of formation and apparent relative movement in longitude of spots (groups) in some RS CVn binaries (Catalano 1983, Rodono 1986), but on a much more rapid time scale.

Personal experience in the use of Althesin in painless childbirth is reported. The anaesthetic is held to have no effect on the foetus and the technique using Althesin and acetylsalicylate of lysine is considered the correct one. If properly applied, it offers the foetus complete wellbeing during labour and enables the mother to overcome the psychophysical stress of an event which is too often accepted with inherited feelings of ancestral fear.

Tracking data from synchronous earth's satellites can be analyzed to provide the resonant geopotential coefficients, mainly C22 and S22 which represent the ellipticity of the earth's equator. Very accurate tracking techniques (LASER, Doppler) could in principle be used to improve the present knowledge of these coefficients but nongravitational perturbations on the satellite orbit, in particular solar radiation pressure, cannot be modeled to the same high accuracy unless the satellite is an ad hoc geophysical satellite. On the other hand, geosynchronous satellites currently used for telecommunication purposes can be easily tracked with moderate size large field telescopes measuring the satellite angular coordinates with respect to some catalogue field stars. The accuracy is at least 2 arc sec (≃ 400 m), i.e., much worse than the accuracy of the LASER data but surely comparable to longitude errors due to the radiation pressure model. Moreover, optical tracking does not need any onboard device and is easily accomplished. We conclude that the organization of a worldwide optical tracking campaign would allow an improvement in the knowledge of the long-wavelength geoid by at least one order of magnitude, and this is very interesting for many geophysical purposes.

One of the outstanding features of RS CVn-type binaries is the changing shape of the so called “wave-like distortion” or “photometric wave” (PW) and its phase migration on the light curve (LC). Here we present a preliminary analysis of the observations of the following objects: CQ Aur, RU Cnc, VV Mon and SZ Psc. For each system we have derived the amplitude and phase of the PW maximum and its migration rate.

We present a complete set of yearly seasonal light curves (LC) of RS CVn obtained from 1963 to 1982 at Catania Observatory, integrated with two LCs obtained by Ludington (1978) in 1975 and 1976. This unique observation set vividly shows (Figure l) the migrating outside of eclipse “photometric wave” (PW), which was first evidenced by Catalano and Rodono (1967) and it is now considered the distinctive photometric feature of RS CVn binaries as well as of other spotted stars. By attributing the PW to surface inhomogeneities, or spots, whose visibility is modulated by the spotted star rotation, the present PW migration toward decreasing orbital phases indicates that the angular rotation of the KOIV spotted component is slightly lower than the orbital one. An inspection of Figure 1 readly shows that the almost sinusoidal PW has been fairly stable from 1963 up to 1981, when a double-peaked wave, still present in the 1982 LC, developed. Most probably the “unusual” 1949 LC by Keller and Limber (1951) and the 1976 one by Ludington (1978) were obtained at a similar activity phase.

Radio emission from close binary systems has long been detected in Algol and other systems. RS CVn systems have been found to be the most powerful and active. The RS CVn binaries are also known to show strong chromosferic and transition region emission line fluxes, that are one or two orders of magnitude higher than those from single stars of similar spectral type. This enhanced activity seems to be connected to the rapid rotation due to the tidal interaction in the system. The Algol binaries are semi-detected close binary systems formed by an early type main sequence primary and a late type giant secondary, while in the RS CVn both components are late type stars of about the same mass, the secondary being a giant or subgiant.

Rotation periods of late main sequence F8-M0 stars are studied as a function of the age. It is shown that for a given mass the rotation period during the main sequence increases as t 1 2 with a rate larger for smaller masses. Time-scale for the angular momentum loss of solar-type stars agrees with a braking confined to the convective envelope.

The tracking of synchronous satellites, combined with an orbit propagation model of comparable accuracy, allows the determination of the resonant geopotential coefficients (l-m even) of low degree l (mainly C22 and S22,which correspond to the Earth’s equator ellipticity). The radio tracking techniques used in the sixties with the first telecommunication satellites (Wagner 1965;1966) were not very accurate, so that the resulting relative accuracy in was not better than few percents.In the present situation, the coefficients C22, S22 relevant for synchronous orbits derived within the existing global models show rather large discrepancies going from 10−3 to 10−1 of their values. Much more accurate tracking techniques are now available (LASER, Doppler twin band), but only the synchronous satellite SIRIO2, scheduled for launch by ESA in 1982,will have a laser retroflector array on board; no synchronous satellite has — nor is planned to have — the required payload on board to allow Doppler twin-band tracking. The ground laser stations tracking SIRIO2 will provide ranging data with an uncertainty in the radial direction less than 1 m. Due to the bad geometry of the range measurements, the corresponding uncertainty in longitude will be about 10 times larger, providing, in principle, a relative accuracy in C22,S22 of the order of 10−5. Unfortunately the results which could be obtained by using LASER data are seriously limited by radiation pressure perturbations (Anselmo et al.,1981),which are very difficult to model (unless ad hoc spherical or very expensive drag-free satellites are used). The bad modelling of the radiation pressure perturbation causes the longitude uncertainties to grow up to 100÷1000m, so that the resulting relative accuracy in C22,S22 will not be anyway better than 10−3÷10−4.

From observational data on rotation periods and ages we deduce the evolution of surface rotational velocity of low-mass main sequence stars from the age of the Pleiades to the solar age. The t1/2 increase of the rotation period is shown to apply to stars of man between 1.1 and 0.5 solar masses with a rate larger for smaller masses. It is shown that time scale of the solar wind braking action is consistent with an angular momentum transport from the radiative core to envelope but with a rate not sufficient to justify the internal rotation deduced from solar oscillations.

The characteristic optical light curves of RS CVn — and BY Dra-type variables are believed to represent non-uniform distribution of dark spots akin to sunspots which are revealed by rotation. By analogy with the Sun, strong magnetic fields probably underlie this phenomenon, extending upwards into the chromosphere and corona, enhancing the emission from regions that overlie the spots. Previous work on the BY Dra variable AU Mic (Ref.1) did not clarify whether the fluxes from chromospheric and transition region lines were rotationally modulated in the sense that the phase of maximum emission was in register with spot visibility or minimum light. This important question prompted the need for further collaborative IUE, optical and radio work.

Continuing our previous analysis of the chromospheric emission (Blanco et al.,1974), absolute fluxes of the K emission line have been evaluated from 10 A mm−1 spectrograms of the O. C. Wilson collection for 31 F5-K7 main sequence stars and 172 G2-M5 giants.

On the ground of extensive photoelectric observations of RS CVn made at Catania since 1963 several photometric peculiarities of this system are analysed.

We report the discovery of the first low–mass pre–main sequence eclipsing binary among a sample of double-lined spectroscopic binaries in the Orion star forming region found in a previous high-resolution spectroscopic investigation on ROSAT–discovered weak-T Tauri stars. Here we present the preliminary results from the combined analysis of the spectroscopic orbit and B and V light–curves, using data available till spring 2000. We then compare the fundamental stellar parameters derived from the orbital solution with those inferred from some widely used theoretical evolutionary models.

The dependence on the temperature of photospheric line-depth ratios (LDRs) in the spectral range 6190-6280 A is investigated by using a sample of 174 ELODIE Archive stellar spectra of luminosity class from V to III. The rotational broadening effect on LDRs is also studied. We provide useful calibrations of effective temperature versus LDRs for giant and main sequence stars with 3800, Comment: 10 pages, 12 figures, Accepted by AN

Gray and collaborators have recently demonstrated that line-depth ratios are a powerful tool for temperature discrim- ination, able to resolve dierences10 K. The method has been applied to detect temperature variations in the 5-15 K range due to activity cycles (e.g. Gray et al. 1996a, 1996b) or to rotation modulation produced by large surface features, called "star-patches", like that detected in Boo A by Toner & Gray (1988). Cool starspots of a few tenths of the stellar surface produce bumps in a line profile, which migrate through the line profile allowing Doppler-imaging in fast rotating stars. In the hypothesis that in slowly-rotating stars the passage of dark spots pro- duces modulation of the center line depth of dierent amount in lines of dierent sensitivity to temperature, we have made test observations on three active binaries of the RS CVn type. Based on observations made at the Catania Astrophysical Observatory at a resolution R= 14 000, we show that line-depth ratios can be eectively used to determine spot temperatures of active binary systems. Using, on average, ten line pairs, selected in the 6100-6300 A wavelength range, with the help of observations of 30 main sequence and giant stars, we have derived a calibration relation of line-depth ratios (LDR) in an absolute temperature scale, taking into account the gravity eect in the calibration relation. Single LDRs converted to temperature through the calibration relations have led to clear rotational modulation of the average surface temperature with amplitudes of 177 K, 119 K, and 127 K for VY Ari, IM Peg and HK Lac, with average estimated errors of about 10 K. We show that the observed temperature variation amplitude allows us to define a minimum fractional spotted area coverage as a function of spot-photosphere temperature ratio. Adopting the maximum value of average temperature, determined from the LDRs, as that of the unspotted photosphere, we computed the average spot temperature corresponding to the minimum spot coverage. Although not univocally constrained, the temperature dierence (T = Tph Tsp) obtained for the three systems,T= 890 K for VY Ari,T= 750 K for IM Peg, andT= 810 K for HK Lac, are in good agreement with values derived with other methods.

Fractionation of the light petroleum extract of the aerial parts of Carduus getulus Pomel afforded, in addition to taraxasterol acetate and taraxasterol, erythrodiol 3-acetate which has never been reported in the Compositae before.