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Context. In recent years, our understanding of solar-like oscillations from main sequence to red giant stars has improved dramatically thanks to pristine data collected from space telescopes. One of the remaining open questions focuses on the observational identification of solar-like oscillations in pre-main sequence stars. Aims. We aim to develop an improved method to search for solar-like oscillations in pre-main sequence stars and apply it to data collected by the Kepler K2 mission. Methods. Our software APOLLO includes a novel way to detect low signal-to-noise ratio solar-like oscillations in the presence of a high background level. Results. By calibrating our method using known solar-like oscillators from the main Kepler mission, we apply it to T Tauri stars observed by Kepler K2 and identify several candidate pre-main sequence solar-like oscillators. Conclusions. We find that our method is robust even when applied to time-series of observational lengths as short as those obtained with the TESS satellite in one sector. We identify EPIC 205375290 as a possible candidate for solar-like oscillations in a pre-main sequence star with νmax ≃ 242 μHz. We also derive its fundamental parameters to be Teff = 3670 ± 180 K, log g = 3.85 ± 0.3, v sin i = 8 ± 1 km s−1, and about solar metallicity from a high-resolution spectrum obtained from the Keck archive.

The area of the research is natural geosystem preservation in geoconstruction. The aim of the research is introduction of information assessment of preservaton level using total geoecological parameter in geoconstruction. Three features were chosen as the main geoecological information features of the estimate, prediction and geosystem preservation management, they are: natural raw materials consumption, fuel consumption and useful properties of a mineral geostructure with the end of the life-cycle. Rating method is suggested as a method of the rasearch;it includes conversion of the properties, using certain mathimatical operations into dimensionless values named index of properties. By determining weight factors with the help of expert assessment and bydetermining the sum of productions of indices and coefficients as total geoecological parameter, the study shows the relationship of the latter with the values of the real consumption of natural raw materials, fuel and useful properties of wastes with the end of the life-cycle of a geostructure. Also the study suggests the achieved levels of the preservation and predicted increase of the level takinginto consideration the total geoecological parameter. The results can be used for estimate of any geotechnology in the preservation aspect.

In continuation of the program formulated in Paper I we present results of long-slit spectroscopy with the Russian 6m telescope of five more objects from the Vorontsov-Velyaminov Atlas and Catalogue of Interacting galaxies. These are the galaxies for which the interaction is not evident, although all of them are classified as multiple systems (usually as ``nests'', ``chains'' and similar systems). The spectrophotometry data enable us to derive for all galaxies abundances of O, and for some of them abundances of N, Ne and S. For two of them chemical abundances are given for the first time. In spectra of three of the studied galaxies [Oiii]4363 line is measured, and T_e and oxygen abundance are derived by the classical method. For the two others, empirical methods are used. For all 5 galaxies, the radial velocity distribution along the slit was obtained in the Ha-line. The studied galaxies represent a rather mixed sample: from very low luminosity irregular galaxies, like VV 499 (DDO 053), to rather bright VV 523 (NGC 3991). Their metallicities vary from Z=1/25 Zo for VV 499 to 1/2 Zo for VV 523. The morphology of these galaxies ranges between typical dIrr (VV 080) through ring-like (VV 131) to clumpy Irr (VV 523). Position--Velocity diagrams in the Ha-line along the galaxy body imply the existence of large-scale ionized gas outflows/supershells around the sites of intense current and/or recent SF activity. Sizes of supershells vary in the range of several hundred pc to about 2 kpc. For all studied galaxies we examine their local environment and indicate the nearest neighbouring objects capable of inducing the observed enhanced star formation., Accepted to A&A 29.11.2002. A&A printer format, in total 18 pages, all figures are given with reduced resolution. The full resolution figures are in the paper version in one ps-gzippd file (1.3 Mbt) on this http://precise.sao.ru/Laboratory/Publications/2003/ms3026.ps.gz

The study of group properties of the extremely metal-deficient gas-rich local dwarfs is very promising for the understanding the galaxy formation process at high redshifts. About 20 such objects have been picked up from the literature in the recent review by Kunth & Ostlin(2000). However part of these galaxies got low metallicity as a result of earlier observations, and can have rather large uncertainties in their cited element abundances. Before to perform the detailed studies of such galaxies as of some extreme group, it is useful to revise their metallicities. We present the results of the SAO 6m telescope spectrophotometry of two Blue Compact Galaxies (BCG) reported from earlier studies as very metal-poor objects. Well measured [O III] line 4363 A allows to deduce the temperature in HII regions and get reliable abundances of chemical elements. For UM 133 we derive 12+log(O/H) = 7.63+/-0.02, coincident with the published value. UM 382, according to our data, is significantly more metal-rich: its 12+log(O/H) = 7.82+/-0.03 in comparison to the published value 7.45. The third galaxy, UM 283 seems have got its very low 12+log(O/H) = 7.59 due to a misprint. We used its published emission line intensities and derived instead the value of 7.95. Thus the latter two galaxies should NOT be considered as the extremely metal-poor BCGs., Comment: 5 pages, 2 figures, A&A in press

We present the second part of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO – Special Astrophysical Observatory, Russia) which is based on the digitized objective-prism photoplates database of the Hamburg Quasar Survey (HQS). The main goal of the project is the search for emission-line galaxies (ELG) in order to create a new deep sample of blue compact/Hii galaxies (BCG) in a large sky area. Another important goal of this work is to search for new extremely low-metallicity galaxies. In this paper we present new results of spectroscopy obtained with the 6 m Russian telescope. The main ELG candidate selection criteria applied are blue or flat enough continuum (near λ4000 A) and the presence of strong or moderate [Oiii]λλ4959, 5007 A emission lines recognized on digitized prism spectra of galaxies with the survey estimated B-magnitudes in the range 16 − 19. 5. No other criteria were applied. The spectroscopy resulted in detection and quantitative spectral classification of 134 emission-line objects. For 121 of them the redshifts are determined for the first time. For 13 ELGs known before emission line ratios are presented at first time. 108 of 134 emission-line objects are classified as BCG/Hii galaxies and probable BCGs, 6 – as QSOs, 1 – as Seyfert galaxy, 1 – as super-association in a dwarf spiral galaxy, 2 – as probable LINERs, 14 are low excitation objects – either of starburst nuclei (SBN), or dwarf amorphous nuclei Send offprint requests to: sap@sao.ru ? Deceased September 22, 1996. 1 Tables 2 to 6 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html. Figures A1 to A13 will be made available only in the electronic version of the journal. Appendix A is only available at http://www.edpsciences.com starburst galaxy (DANS) type, and 2 – nonclassified. 23 galaxies did not show significant emission lines. The five most metal-deficient BCGs discovered have oxygen abundances log(O/H)+12 in the range 7.4 to 7.7, similar to the most metal-deficient BCGs known before.

We present the second part of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO – Special Astrophysical Observatory, Russia) which is based on the digitized objective-prism photoplates database of the Hamburg Quasar Survey (HQS). The main goal of the project is the search for emission-line galaxies (ELG) in order to create a new deep sample of blue compact/Hii galaxies (BCG) in a large sky area. Another important goal of this work is to search for new extremely low-metallicity galaxies. In this paper we present new results of spectroscopy obtained with the 6 m Russian telescope. The main ELG candidate selection criteria applied are blue or flat enough continuum (near λ 4000 A) and the presence of strong or moderate [Oiii] 4959, 5007 A emission lines recognized on digitized prism spectra of galaxies with the survey estimated B -magnitudes in the range . No other criteria were applied. The spectroscopy resulted in detection and quantitative spectral classification of 134 emission-line objects. For 121 of them the redshifts are determined for the first time. For 13 ELGs known before emission line ratios are presented at first time. 108 of 134 emission-line objects are classified as BCG/Hii galaxies and probable BCGs, 6 – as QSOs, 1 – as Seyfert galaxy, 1 – as super-association in a dwarf spiral galaxy, 2 – as probable LINERs, 14 are low excitation objects – either of starburst nuclei (SBN), or dwarf amorphous nuclei starburst galaxy (DANS) type, and 2 – nonclassified. 23 galaxies did not show significant emission lines. The five most metal-deficient BCGs discovered have oxygen abundances log(O/H)+12 in the range 7.4 to 7.7, similar to the most metal-deficient BCGs known before.

We present rst results 1 of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS therein, SAO { Special Astrophysical Observatory, Russia) which is based on the digitized objective-prism photoplates database of the Hamburg Quasar Survey (HQS). The main goal of this survey is the search for emission-line galaxies (ELG) in order to create a new deep sample of blue compact galax- ies (BCG) in a large sky area. Another important goal of this work is to search for new extremely low-metallicity galaxies. We present the rst results of spectroscopy ob- tained with the 2.2 m telescope at the German-Spanish Observatory at Calar Alto, and with the 6 m telescope at the Russian Special Astrophysical Observatory. The primary ELG candidate selection criteria applied were a blue continuum (near 4000 A) and the presence of emission lines close to 5000 A recognized on digitized prism spectra of galaxies with magnitudes in the range B =1 6 : 0 19: m 5. The spectroscopy resulted in the de- tection or/and quantitative spectral classication of 74 emission-line objects. Of them 55 are newly discovered, and 19 were already known as galaxies before. 11 of the latter have redshifts and are known ELGs. For most of the known galaxies emission line ratios were measured for the rst time and an improved classication is pre- sented. 47 objects are classied as BCGs, one as Sy2 galaxy, six as possible LINERs, and four as new QSOs.

Aims. Very small asteroids (VSAs) are thought to be the building blocks of larger asteroids and, as such, are interesting to study. Many of these monolithic or deeply fractured objects display rapid rotations with periods as short as several minutes. Observations of such asteroids can reveal their spin limits, which can be related to the tensile strength of their interiors. The evolution of the spins of these objects is primarily shaped by the YORP effect, the theory of which needs comparison with observations. Methods. With the 10 m SALT telescope, we observed VSAs belonging to near-Earth asteroids. The obtained lightcurves were used to derive synodical periods of rotation, amplitudes, and elongations of these bodies. Results. Results for 14 rapidly rotating asteroids were reported in the first paper in this series. Here we show lightcurves of 2 fast rotators, 9 objects with periods ≥1 h, and a possible non-principal axis rotator. We also list negative detections that most probably indicate asteroids with long periods and/or low amplitudes. Combining our results with the data from the literature, we obtain a set of 79 near-Earth VSAs with a median period of 0.25 h (15 min). By adjusting the spin limits predicted by theory to those observations, we find tentative evidence that the tensile strengths of VSAs, after scaling them to the same size, are of the same order as the minimum tensile strengths of stony meteoroids that undergo fragmentation under the atmospheric load.

Aims. We report first results from our extensive survey of the very small (H > 21.5 mag) near-Earth asteroids. Our aim was to obtain photometric lightcurves for these faint, fast moving objects and to measure their rotation periods and amplitudes of light variations. These parameters can be used to make statistical analysis of the still little known population of the smallest asteroids, test present theories of the YORP effect as well as to study their spin limits, which are connected with their internal structure. Methods. Due to the faintness of the targets and the expected short periods of rotation, observations were performed with the large, 10-m SALT telescope in SAAO (South Africa). For most asteroids, V filter images with exposure times of 5–60 s were obtained with the instrument’s SALTICAM’s CCD camera. Even though the non-sidereal tracking was not available, the SALTICAM’s relatively large field-of-view of 8 � × 8 � helped to perform the relative photometry of the fast-moving targets. Results. The presented asteroids have synodic periods ranging from 77 s to 44 min, effective diameters from 21 to 94 m, and significantly elongated shapes.