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Motivated by previous studies about asteroids situated between Jupiter and Saturn, where long-term stable orbits with small eccentricities and low inclinations have been identified, we extend this research by placing an Earth-mass planet in the region between Jupiter and Saturn. We pursued numerical integrations of the equations of motions for the outer solar system encompassing Jupiter, Saturn, Uranus, and Neptune, as well as the additional Earth-mass planet. This 6-body system has been integrated with the Lie method for up to 500 Myr. The default initial stable zone for the Earth-mass planet has been assumed between 7.04 au and 7.31 au based on the results from previous studies by our group. We explored each region separately for 360 Earth-mass planets (assuming different mean anomalies) and inspected the respective escape times (ETs). The overall picture shows that the most stable orbits occur between 7.12 au and 7.28 au. Furthermore, the mean of the ETs for all 360 mean anomalies between 7.24 au and 7.12 au gradually decreases from ET=11 Myr to 0.9 Myr, although smaller values are obtained for the median due to outliers. To check the role of stability of the Earth-mass planet depending on its initial inclination, we focused on three regions (i.e., 7.23 au, 7.24 au, and 7.25 au) in terms of their ETs assuming i = 1°, 3°, and 5°; however, no significant differences were found. Hence, the general possibility of an Earth-mass planet situated between Jupiter and Saturn in the Solar System’s distant past is highly notable, although it would have been a transient event.

Thirty-year simulations of seasonal snow cover in 22 physically based models driven with bias-corrected meteorological reanalyses are examined at four sites with long records of snow observations. Annual snow cover durations differ widely between models but interannual variations are strongly correlated because of the common driving data. No significant trends are observed in starting dates for seasonal snow cover, but there are significant trends towards snow cover ending earlier at two of the sites in observations and most of the models. A simplified model with just two parameters controlling solar radiation and sensible heat contributions to snowmelt spans the ranges of snow cover durations and trends. This model predicts that sites where snow persists beyond annual peaks in solar radiation and air temperature will experience rapid decreases in snow cover duration with warming as snow begins to melt earlier and at times of year with more energy available for melting.

Savannah-type ecosystems account for 26–30% of global gross primary productivity GPP with water being one of the major driving factors. In Europe, savannah-type woodlands cover an area of about 1.5 million ha. Here, the recent past has shown a significant decrease of precipitation P in winter and spring as well as decrease of total annual precipitation. Strong effects on local water balance and carbon sink strength have thus been reported due to changes in precipitation regime. The objective of this study is to quantify the impact of the extreme drought event in 2012 on the water balance, gross primary productivity and carbon sink strength of a typical Portuguese cork-oak woodland (montado) compared to the wet year 2011. Physiological responses of the dominant tree species Quercus suber (L.) are disentangled, employing combined photosynthesis and stomatal conductance modelling. Precipitation effectiveness ET / P increased from 86% in 2011 to 122% in the dry year 2012 due to deep soil or ground water access of the Q. suber trees leaving no water for ground water replenishment. Understorey and overstorey GPP were strongly reduced by 53% and 28%, respectively, in 2012 compared to 2011 due to the late onset of the autumn rains in 2011 and an additional severe winter/spring drought. However, the ecosystem was still a carbon sink in both years but with a 38% reduced sink strength under extreme drought in 2012 compared to 2011. The combined photosynthesis-stomatal conductance model yielded best results if it was allowed to adjust photosynthetic and stomatal parameters simultaneously. If stomatal response was modelled with the Leuning approach, which allows for a different sensitivity to vapour pressure deficit, the stomatal model parameters were highly coupled. A change in either of the parameters needed to be compensated by the other to guarantee a stable sensitivity of stomatal conductance to assimilation, independently from variations in vapour pressure deficit. The Q. suber trees showed a 31% reduced stomatal conductance during the drought period 2012 compared to 2011 due to water supply limitations. In response to reduced leaf internal CO2 availability, the trees strongly reduced apparent maximum carboxylation rate by 39% in 2012 compared to 2011. Unexpectedly, the optimum temperature Topt of maximum electron transport rate decreased during the drought period, enhancing the susceptibility of the trees to high temperature stress during the summer. Our results suggest that, if the trend of decreasing annual precipitation and changed precipitation pattern on the Iberian Peninsula continues, sustained effects on local ground water reservoirs, understorey species composition and tree mortality have to be expected in the long term. To successfully model the effect of drought on the montado ecosystem, variable apparent maximum carboxylation rate Vc,max, stomatal conductance parameter m and vapor pressure deficit sensitivity parameter D0 need to be incorporated in photosynthesis-stomatal conductance modelling.

Surface preparation processes prior adhesive bonding of the metallic materials used in aeronautical industry like aluminium alloys, titanium alloys and stainless steels, were reviewed. Peel and three point bending tests were carried out to assess the behaviour of the bonded joints at the initial state and after ageing. The test results indicate that anodizing processes exhibit generally a high performance level in comparison with etching processes. The chemical and physical properties of the surfaces were determined. Correlations between bond durability, surface morphology and oxide film composition were sometimes established.

I present first results of a study about propagating radial pulsation modes in the outer atmosphere of Arcturus (K1.5 III). Mechanical energy input is explicitly taken into account by treating shock wave dissipation. I investigate the influence of different wave frequencies on the mass loss behavior of the star. I show that significant time-averaged mass loss can only be produced when periods larger than 5 x 105 s (∼ 1 week) are employed. The initial atmosphere I use extends from 1.2 R* up to 11.8 RR*. All wave models are adiabatic. I found that the mass loss rates and the final flow speeds obtained are extremely sensitive to the wave periods. In a certain regime the effect of increasing the period by a factor of 4 is to increase the corresponding mass loss rate by four orders of magnitude. I note that the mass loss rate and final flow speed of the wind for a 5.6 x 105 s period wave are somewhat close to the observed values. A more complete discussion regarding mass loss generation in Arcturus has been presented by Cuntz (1990). Recent observations of low-amplitude radial velocity variations in the photosphere of Arcturus provide evidence that the theoretically predicted mass loss frequencies might exist. Belmonte et al. (1990) presented evidence for a ∼8.3 d period with an amplitude of ∼50 m s-1, which they attributed to the fundamental radial pulsation mode. Further studies are in progress (Larson et al. 1992). I note that if the 8.3 d period is real than it would be sufficiently large to support continuous mass loss. Judge & Stencel (1991) argued that the mechanical energy in the observed disturbances could be ∼15 times greater than the energy required to drive the wind. For other stars than Arcturus the required minimum mass loss periods can be estimated as PML ∼ R*.

In addition to his review paper, Hammer presented some results in poster format. The purpose of this poster was two-fold: first, to list and criticize previous explanations for the coronal/wind dividing line; and second, to point out that this list is incomplete — there exists a broad class of additional possibilities. A hot corona can exist on top of a cool chromosphere only if certain requirements are fulfilled, some of which might break down for the non-coronal stars. For the first topic, the list and criticism of previous explanations, the reader is referred to Hammer (in Solar and Stellar Physics, Proc. 5th European Solar Meeting, Titisee, 1987, E. H. Schroter and M. Schussler, eds., Springer, p77).

We investigate the propagation of a strong shock obtained in a time-dependent acoustic wave model of the outer atmosphere of Arcturus. Radiation damping due to CO and SiO molecules is considered. The development of the shock leads to a transition between a cool (molecule dominated) atmosphere and a hot chromospheric feature with a temperature similar to the semiempirical model of Ayres and Linsky. This behaviour suggests a possible explanation for the inhomogeneous chromospheric structures of late-type stars which are proposed by some observers.

Mass loss generated by radiatively damped acoustic waves is investigated. We find that a persistent wave energy flux leads to extended chromospheres. Mass loss is quite likely produced if the wave field retains a transient character and if large wave periods are used.