Remarks on some tardigrades of the African fauna with the description of three new species of Macrobiotus Schultze 1834

Ten species of tardigrades are recorded. Three of them, Macrobiotus radiatus, Macrobiotus vanescens, and Macrobiotus iharosi are new for science; two species, Macrobiotus sapiens Binda & Pilato 1984 and Isohypsibius kristenseni Pilato et al. 1989, are new for the African fauna. Macrobiotus radiatus n. sp. differs from the other species of the harmsioorthi group in the characters of the eggs and in other characters regarding various structures (buccal armature, or placoids length, or the insertion point of the stylet supports, or the claws length). Macrobiotus vanescens n. sp. is similar to Macrobiotus richtersi Murray 1911 and to Macrobiotus peteri Pilato et al. 1989 but differs from them in some characters regarding the bucco-pharyngeal apparatus, the claws and the eggs. Macrobiotus iharosi n. sp. differs from Macrobiotus echinogenitus Richters 1904 in the characters of the eggs, and from Macrobiotus sapiens Binda & Pilato 1984 in some characters of the bucco-pharyngeal apparatus and of the claws

Orbital solutions for SB2 systems with a HgMn component

From a new set of spectroscopic observations we determined orbital parameters of six SB2 systems with one or both components being HgMn stars.We slightly refined the orbital periods for HD 32964, HD 173524, HD 174933 and HD 216494. Our results for HD 358 are in agreement with the previous literature studies. Regarding HD 33647, our orbital period is shorter than previous determinations. HD 173524 is a triple system. From the variations of the γ-velocity deduced from our and literature data, we refined the orbital period and we estimated the eccentricity of the third companion, for which we get e ≈ 0.13 and Porb = 36 ± 3 years. HD 191110 and HD 216494 seem to be the only synchronous SB2 within our sample. Following the hypothesis of rotational axes perpendicular to the orbital plane, we estimated the angle of the orbital plane to the line of sight. We identified in our spectra the signature of the Hβ of the third component of HD 216494 and we highlight a slight variation of the γ-velocity due to the presence of this component.Based on observations collected at the Stellar Station ``M. G. Fracastoro'' of the Catania Astrophysical Observatory, Italy.Appendix A is only available in electronic form at http://www.edpsciences.or

Caratterizzazione del sensore CMOS GSENSE-4040 della camera C4 della Moravian

Nel presente rapporto si riportano i risultati di una caratterizzazione del sensore di tipo CMOS GSENSE-4040 utilizzato dalla camera C4 della Moravian, la quale è stata acquistata dall'Osservatorio Astrofisico di Catania per effettuare imaging al telescopio da 91 cm della sede M.G. Fracastoro (Serra La Nave, Etna). Lo scopo principale di questo lavoro è stato quello di controllare le specifiche di questa camera per verificare se fosse adeguata per le nostre esigenze. In particolare abbiamo misurato il guadagno (elettroni/ADU), il rumore di lettura, la efficienza quantica, il livello del Dark e la linearità di risposta di questo sensore

The LAMOST spectroscopic survey of stars in the Kepler field of view: Activity indicators and stellar parameters

We summarize the results of the completed first round of the LAMOST-Kepler project, and describe the status of its on-going second round. As a result of the first round of this project, the atmospheric parameters (T eff , log g , and [Fe/H]), the spectral classification (spectral type and luminosity class), and the radial velocities (RV ) have been measured for 51,385 stars. For 4031 stars, we were able to measure the projected rotational velocity, while the minimum detectable v sin i was 120 km s−1 . For 8821 stars with more than one observation, we computed the χ -square probability that the detected RV variations have a random occurrence. Finally, we classified 442 stars as chromospherically active on the basis of the analysis of their Hα and Ca II-IRT fluxes. All our results have been obtained from the low-resolution (R ∼ 1800) spectroscopic observations acquired with the LAMOST instrument

HD 226766: a hierarchical SB3 system with two twin Am stars

In this paper, we present a detailed revision of the orbital parameters and the first quantitative abundance analysis of the spectroscopic triple system HD 226766. By means of a simultaneous fit of the radial velocities of all the three components, we derived precise orbital parameters for the system, in particular inner pair has P(d) = 31.9187 ± 0.0001, e = 0.28 ± 0.01, and MA/MB = 1.03 ± 0.03, while the C component orbits around the inner pair with a period of P(d) = 1615 ± 59 in a very eccentric orbit (e = 0.54 ± 0.11). From the fit of the Hβ and Hα profiles, we determined the effective temperatures and surface gravities of each component of the inner pair: Teff = 8600 ± 500 K and log g = 3.8 ± 0.2 for HD 226766 A and Teff = 8500 ± 400 K and log g = 4.0 ± 0.2 for HD 226766 B. In the hypothesis that component C is a main sequence star (log g = 4.0) we derived Teff = 8000 ± 500 K. Rotational velocities have been estimated by modeling the profiles of metallic lines: v sin i = 13 ± 1 km s-1 for inner pair and v sin i = 150 ± 20 km s-1 for the C component. We find that the inner pair is heterogeneous from the point of view of the chemical composition: both stars are very similar and show chemical anomalies typical of Am stars. With some hypothesis about the masses of the components, we estimated the orbital inclination angle for the inner binary, i = (47 ± 1)○, and for the outer orbit, i = (54 ± 19)○

The behaviour of chemical elements in 62 Am star candidates

In this paper, we present the results of a spectroscopic campaign devoted to ascertain the actual nature of a sample of 155 objects reported as uncertain peculiar stars in the General catalogue of Ap, Am, and HgMn stars. Spectroscopic observations have been obtained with Catania Astrophysical Observatory Spectropolarimeter. We derive for all the objects that appear to be single stars, effective temperature, gravity, rotational and radial velocities, and chemical abundances by spectral synthesis method, then by using an abundance-based criterion we selected 62 Am star candidates. Further, by using the positions of these stars within the theoretical instability strips for δ Sct and γ Dor in the Hertzsprung-Russell diagram, we selected 46 out of 62 candidates to be possible pulsating stars, in particular 42 are candidates δ Sct and four candidates hybrid stars