ABSTRACT
We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (mV = 14.0 mag) by the centaur 2002 GZ32 for 2017 May 20. Our latest shadow path ...prediction was favourable to a large region in Europe. Observations were arranged in a broad region inside the nominal shadow path. Series of images were obtained with 29 telescopes throughout Europe and from six of them (five in Spain and one in Greece) we detected the occultation. This is the fourth centaur, besides Chariklo, Chiron, and Bienor, for which a multichord stellar occultation is reported. By means of an elliptical fit to the occultation chords, we obtained the limb of 2002 GZ32 during the occultation, resulting in an ellipse with axes of 305 ± 17 km × 146 ± 8 km. From this limb, thanks to a rotational light curve obtained shortly after the occultation, we derived the geometric albedo of 2002 GZ32 (pV = 0.043 ± 0.007) and a 3D ellipsoidal shape with axes 366 km × 306 km × 120 km. This shape is not fully consistent with a homogeneous body in hydrostatic equilibrium for the known rotation period of 2002 GZ32. The size (albedo) obtained from the occultation is respectively smaller (greater) than that derived from the radiometric technique but compatible within error bars. No rings or debris around 2002 GZ32 were detected from the occultation, but narrow and thin rings cannot be discarded.
Within our program of physical characterization of trans-Neptunian objects and centaurs, we predicted a stellar occultation by the centaur (54598) Bienor to occur on January 11, 2019, with good ...observability potential. We obtained high accuracy astrometric data to refine the prediction, resulting in a shadow path favorable for the Iberian Peninsula. This encouraged us to carry out an occultation observation campaign that resulted in five positive detections from four observing sites. This is the fourth centaur for which a multichord (more than two chords) stellar occultation has been observed so far, the other three being (2060) Chiron, (10199) Chariklo, and (95626) 2002 GZ
32
. From the analysis of the occultation chords, combined with the rotational light curve obtained shortly after the occultation, we determined that Bienor has an area-equivalent diameter of 150 ± 20 km. This diameter is ~30 km smaller than the one obtained from thermal measurements. The position angle of the short axis of the best fitting ellipse obtained through the analysis of the stellar occultation does not match that of the spin axis derived from long-term photometric models. We also detected a strong irregularity in one of the minima of the rotational light curve that is present no matter the aspect angle at which the observations were done. We present different scenarios to reconcile the results from the different techniques. We did not detect secondary drops related to potential rings or satellites. Nonetheless, similar rings in size to that of Chariklo's cannot be discarded due to low data accuracy.
Within our program of physical characterization of trans-Neptunian objects and centaurs, we predicted a stellar occultation by the centaur (54598) Bienor to occur on January 11, 2019, with good ...observability potential. We obtained high accuracy astrometric data to refine the prediction, resulting in a shadow path favorable for the Iberian Peninsula. This encouraged us to carry out an occultation observation campaign that resulted in five positive detections from four observing sites. This is the fourth centaur for which a multichord (more than two chords) stellar occultation has been observed so far, the other three being (2060) Chiron, (10199) Chariklo, and (95626) 2002 GZ\(_{32}\). From the analysis of the occultation chords, combined with the rotational light curve obtained shortly after the occultation, we determined that Bienor has an area-equivalent diameter of \(150\pm20\) km. This diameter is \(\sim30\) km smaller than the one obtained from thermal measurements. The position angle of the short axis of the best fitting ellipse obtained through the analysis of the stellar occultation does not match that of the spin axis derived from long-term photometric models. We also detected a strong irregularity in one of the minima of the rotational light curve that is present no matter the aspect angle at which the observations were done. We present different scenarios to reconcile the results from the different techniques. We did not detect secondary drops related to potential rings or satellites. Nonetheless, similar rings in size to that of Chariklo's cannot be discarded due to low data accuracy.
We predicted a stellar occultation of the bright star Gaia DR1 4332852996360346368 (UCAC4 385-75921) (m\(_{\rm V}\)= 14.0 mag) by the centaur 2002 GZ\(_{32}\) for 2017 May 20\(^{\rm th}\). Our latest ...shadow path prediction was favourable to a large region in Europe. Observations were arranged in a broad region inside the nominal shadow path. Series of images were obtained with 29 telescopes throughout Europe and from six of them (five in Spain and one in Greece) we detected the occultation. This is the fourth centaur, besides Chariklo, Chiron and Bienor, for which a multi-chord stellar occultation is reported. By means of an elliptical fit to the occultation chords we obtained the limb of 2002 GZ\(_{32}\) during the occultation, resulting in an ellipse with axes of 305 \(\pm\) 17 km \(\times\) 146 \(\pm\) 8 km. From this limb, thanks to a rotational light curve obtained shortly after the occultation, we derived the geometric albedo of 2002 GZ\(_{32}\) (\(p_{\rm V}\) = 0.043 \(\pm\) 0.007) and a 3-D ellipsoidal shape with axes 366 km \(\times\) 306 km \(\times\) 120 km. This shape is not fully consistent with a homogeneous body in hydrostatic equilibrium for the known rotation period of 2002 GZ\(_{32}\). The size (albedo) obtained from the occultation is respectively smaller (greater) than that derived from the radiometric technique but compatible within error bars. No rings or debris around 2002 GZ\(_{32}\) were detected from the occultation, but narrow and thin rings cannot be discarded.
Background and Aims
Numerous descriptions have been made of the wines produced in the past, however, the grapevine genotypes have been poorly recorded. Naming errors are also common, a problem that ...could negatively impact scientific work and cause economic damage to wine markets. The aim of the present work was to compare the accessions from Galicia and Asturias held in the Misión Biológica de Galicia‐Consejo Superior de Investigaciones Científicas and El Encín‐Instituto Madrileño de Investigación y Desarrollo Rural, Agrario y Alimentario collections in Spain in order to resolve synonyms, homonyms and naming errors in both.
Materials and Methods
The accessions of these collections were compared in terms of their leaf and bunch ampelographic characteristics, via simple sequence repeat analysis and via the examination of old photographs and other historic documentation.
Results
The two collections were found to hold 59 distinct genotypes from the two regions. Ten were unique to the Misión Biológica de Galicia‐Consejo Superior de Investigaciones Científicas collection and four to the El Encín‐Instituto Madrileño de Investigación y Desarrollo Rural, Agrario y Alimentario collection – rather fewer than expected. Traces of intra‐genotype variation were seen for some genotypes.
Conclusions
The comparison of the accessions allowed some problems of genotype identity and origin to be identified and resolved. The possible intra‐genotype variation detected should be examined in greater depth. The results also highlight the value of well documented live collections, gathered at different times and curated in different places, for this type of work, as well as in the conservation of world viticultural heritage.
Significance of this Study
These findings open up paths for future research on the material conserved, and its commercial exploitation.
Background and Aims
Wild grapevine, considered the ancestor relative of cultivated vines, has a large gene pool that is currently endangered in Europe. These plants can contribute to improving ...adaptation capacity to stresses due to climate change. The aim of this study was to evaluate the key ampelographic traits to identify true wild individuals supporting the preservation and use of wild populations.
Methods and Results
Prospections performed since 2002 enabled the inventory of 51 localities with wild grapevines, most of which were located along Spanish riverbank forests. A morphological study of 192 individuals grafted in the grapevine collection of El Encín (Alcalá de Henares, Spain) was carried out ex situ, and results were compared with data from 182 Spanish commercial cultivars grown in the same collection. Wild individuals presented morphological differences with cultivars, but only a few significant differences were found within wild individuals when comparing their geographic origin and plant sex. Ten morphological traits were relevant to discriminate wild and cultivated specimens.
Conclusions
Ampelography, supported by previous molecular screening, is recommended to identify wild grape plants, although it is not advisable to establish relationships among wild genotypes by geographical location or gender.
Significance of the Study
Results are expected to contribute to improved discovery, preservation and use of this important phytogenetic resource.
The main phenological stages (budburst, flowering, veraison, and ripeness) of 53 Spanish minority varieties were studied to determine their potential to help winegrowers adapt to climate change ...conditions. In total, 43 varieties were studied in the same location in Spain (Alcalá de Henares, in the Madrid region) and 10 varieties in 5 other regions (Galicia, Navarre, Catalonia, Extremadura, and Andalusia). Other traits of agronomic and oenological interest, such as yield and acidity, were also monitored. The results allow for the grouping of the varieties into several clusters according to the time of ripeness (very early—only for red varieties—and early, intermediate, and late, for both red and white varieties) and yield (high, medium, and low). The total acidity in the grape juice ranged from 3 to 11 g of tartaric acid/L. The average temperatures were higher (up to 3–4 °C during summer) compared to historical averages during the 1957–2021 time period. Advanced phenology phases and reduced acidity are regarded as negative effects of climate change for winegrowing practices. Since some minority varieties showed late or intermediate ripening, high acidity, and high (1 Kg/shoot) or medium (0.5 Kg/shoot) yield, our findings suggest that they may be cultivated in the coming years by winegrowers as an approach to mitigate climate change effects.
Downy mildew is one of the most destructive diseases affecting grapevines (
L.). Caused by the oomycete
(Berk. and Curt.) Berl. and de Toni, it can appear anywhere where vines are cultivated. It is ...habitually controlled by the application of phytosanitary agents (copper-based or systemic) at different stages of the vine growth cycle. This, however, is costly, can lead to reduced yields, has a considerable environmental impact, and its overuse close to harvest can cause fermentation problems. All grapevines are susceptible to this disease, although the degree of susceptibility differs between varieties. Market demands and European legislation on viticulture and the use of phytosanitary agents (art. 14 of Directive 128/2009/EC) now make it important to know the sensitivity of all available varieties, including minority varieties. Such knowledge allows for a more appropriate use of phytosanitary agents, fosters the commercial use of these varieties and thus increases the offer of wines associated with different
, and helps identify material for use in crop improvement programmes via crossing or genetic transformation, etc. Over 2020-2021, the susceptibility to
of 63 minority vine varieties from different regions of Spain was examined in the laboratory using the leaf disc technique. Some 87% of these varieties were highly susceptible and 11% moderately susceptible; just 2% showed low susceptibility. The least susceptible of all was the variety Morate (Madrid, IMIDRA). Those showing intermediate susceptibility included the varieties Sanguina (Castilla la Mancha, IVICAM), Planta Mula (Comunidad Valenciana, ITVE), Rayada Melonera (Madrid, IMIDRA), Zamarrica (Galicia, EVEGA), Cariñena Roja (Cataluña, INCAVI), Mandrègue (Aragón, DGA) and Bastardo Blanco (Extremadura, CICYTEX). The highly susceptible varieties could be differentiated into three subgroups depending on sporulation severity and density.
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