116 research outputs found
First observations and magnitude measurement of Starlink's Darksat
Measure the Sloan g' magnitudes of the Starlink's STARLINK-1130 (Darksat) and
1113 LEO communication satellites and determine the effectiveness of the
Darksat darkening treatment at 475.4\,nm. Two observations of the Starlink's
Darksat LEO communication satellite were conducted on 2020/02/08 and 2020/03/06
using a Sloan r' and g' filter respectively. While a second satellite,
STARLINK-1113 was observed on 2020/03/06 using a Sloan g' filter. The initial
observation on 2020/02/08 was a test observation when Darksat was still
manoeuvring to its nominal orbit and orientation. Based on the successful test
observation, the first main observation was conducted on 2020/03/06 along with
an observation of the second Starlink satellite. The calibration, image
processing and analysis of the Darksat Sloan g' image gives an estimated Sloan
g' magnitude of at a range of 976.50\,km. For STARLINK-1113 an
estimated Sloan g' magnitude of at a range of 941.62\,km was
found. When scaled to a range of 550\,km and corrected for the solar and
observer phase angles, a reduction by a factor of two is seen in the reflected
solar flux between Darksat and STARLINK-1113. The data and results presented in
this work, show that the special darkening coating used by Starlink for Darksat
has darkened the Sloan g' magnitude by \,mag, when the range is
equal to a nominal orbital height (550\,km). This result will serve members of
the astronomical community modelling the satellite mega-constellations, to
ascertain their true impact on both the amateur and professional astronomical
communities. Concurrent and further observations are planned to cover the full
optical and NIR spectrum, from an ensemble of instruments, telescopes and
observatories.Comment: Accepted for publication in A&A Letters. 5 pages, 2 figures and 4
table
On Communicative Education in Non-Linguistic Institute
The problem of communicative education as a condition of modern human development is considered. Different approaches of foreign and Russian researchers to defining of “communicative competence” and “communicative competency” as components of communicative education are described. The methods and forms of work at the lessons of foreign language that the authors uses in the teaching process in the conditions of a non-linguisticuniversity are described. It is concluded that the development of communicative competence in the sphere of foreign language usingis necessary for future specialist, regardless of specialty he receives.Рассматривается проблема коммуникативного образования как условия развития современного человека. Описываются различные подходы зарубежных и российских исследователей к определению понятий «коммуникативная компетенция» и «коммуникативная компетентность» как компонентов коммуникативного образования. Предлагаются методы и формы работы на занятиях по иностранному языку, которые авторы используют в процессе преподавания в условиях неязыкового вуза
Communicative competence in the globalization process
The article deals with different approaches of Russian and foreign researchers to the concept of «communicative competence», specifies its definition, content and structureРассматриваются различные подходы зарубежных и российских исследователей к понятию коммуникативной компетенции, приводятся его определение, содержание и структур
Optical-to-NIR magnitude measurements of the Starlink LEO Darksat satellite and effectiveness of the darkening treatment
Four observations of Starlink's LEO communication satellites, Darksat and
STARLINK-1113, were conducted on two nights with two telescopes. The Chakana
0.6\,m telescope at the Ckoirama observatory (Chile) observed both satellites
on 5\,Mar\,2020 (UTC) and 7\,Mar\,2020 (UTC) using a Sloan r' and Sloan i'
filter, respectively. The ESO VISTA 4.1\,m telescope with the VIRCAM instrument
observed both satellites on 5\,Mar\,2020 (UTC) and 7\,Mar\,2020 (UTC) in the
NIR J-band and Ks-band, respectively. The calibration, image processing, and
analysis of the Darksat images give r\,\,5.6\,mag,
i\,\,5.0\,mag, J\,\,4.2\,mag, and Ks\,\,4.0\,mag
when scaled to a range of 550\,km (airmass ) and corrected for the solar
incidence and observer phase angles. In comparison, the STARLINK-1113 images
give r\,\,4.9\,mag, i\,\,4.4\,mag, J\,\,3.8\,mag,
and Ks\,\,3.6\,mag when corrected for range, solar incidence, and
observer phase angles. The data and results presented in this work show that
the special darkening coating used by Starlink for Darksat has darkened the
Sloan r' magnitude by 50\,\%, Sloan i' magnitude by 42\,\%, NIR J magnitude by
32\,\%, and NIR Ks magnitude by 28\,\%. The results show that both satellites
increase in reflective brightness with increasing wavelength and that the
effectiveness of the darkening treatment is reduced at longer wavelengths. This
shows that the mitigation strategies being developed by Starlink and other LEO
satellite operators need to take into account other wavelengths, not just the
optical. This work highlights the continued importance of obtaining
multi-wavelength observations of many different LEO satellites in order to
characterise their reflective properties and to aid the community in developing
impact simulations and developing mitigation tools.Comment: Accepted for publication in A&A, 10 pages, 10 figures, 3 table
Factor Structure and Measurement Invariance of the Spanish Burnout Inventory Among Professionals Across 17 Countries and Regions
Studies on the prevalence of burnout in professionals in service organizations who work in direct contact with the clients or users of the organization have concluded that burnout is a serious health disorder that has increased due to the COVID-19 pandemic. A significant advantage of the Spanish Burnout Inventory (SBI) over other instruments is that it provides a broader conceptualization of burnout by including feelings of guilt as a dimension of burnout to explain its development. However, the measurement invariance of the SBI across countries has not been investigated. The purpose of this study was to test the measurement invariance of the SBI among professionals across 17 countries and regions in Europe, Latin America, and Asia, and in different languages. All the countries showed a good fit to the four-factor model, except the Indian sample, which was excluded from the measurement invariance study. Using the alignment method, it was possible to verify the scalar measurement invariance of the four SBI factors across 15 countries and one Spanish region (16 samples). The comparison of estimated latent means indicates that France is the country with the lowest scores on the Enthusiasm factor and the highest scores on the negative factors (Exhaustion, Indolence, and Guilt). In contrast, the Andean countries, Colombia, Peru, and Ecuador, show the highest latent means on the Enthusiasm factor and the lowest means on the negative factors. These results support the validity of the SBI in the countries and regions in Europe and Latin America included in this study
Transit timing variations in the WASP-4 planetary system*
Abstract Transits in the planetary system WASP-4 were recently found to occur 80 s earlier than expected in observations from the TESS satellite. We present 22 new times of mid-transit that confirm the existence of transit timing variations, and are well fitted by a quadratic ephemeris with period decay dP/dt = −9.2 ± 1.1 ms yr−1. We rule out instrumental issues, stellar activity and the Applegate mechanism as possible causes. The light-time effect is also not favoured due to the non-detection of changes in the systemic velocity. Orbital decay and apsidal precession are plausible but unproven. WASP-4 b is only the third hot Jupiter known to show transit timing variations to high confidence. We discuss a variety of observations of this and other planetary systems that would be useful in improving our understanding of WASP-4 in particular and orbital decay in general
The stellar occultation by Makemake on 2011 April 23
We have taken advantage of a stellar occultation by the dwarf planet Makemake on 2011 April 23, to determine several of its main physical properties. We present results from a multisite campaign with 8 positive occultation detections from 5 different sites, including data from the 8-m VLT and 3.5-m NTT telescopes in Chile, which have very high temporal resolution. Because the star was significantly fainter than Makemake (setting a record in the magnitude of a star whose occultation has been detected), the occultation resulted in a drop of just ~0.3 mag in the lightcurves. From the lightcurves we have been able to determine the size and shape of the body, its geometric albedo and constraints on its atmosphere
High-precision photometry by telescope defocussing - VIII.WASP-22, WASP-41,WASP-42 andWASP-55
We present 13 high-precision and four additional light curves of four bright southernhemisphere transiting planetary systems: WASP-22, WASP-41, WASP-42 and WASP-55. In the cases of WASP-42 and WASP-55, these are the first follow-up observations since their discovery papers. We present refined measurements of the physical properties and orbital ephemerides of all four systems. No indications of transit timing variations were seen. All four planets have radii inflated above those expected from theoretical models of gas-giant planets; WASP-55 b is the most discrepant with a mass of 0.63MJup and a radius of 1.34 RJup. WASP-41 shows brightness anomalies during transit due to the planet occulting spots on the stellar surface. Two anomalies observed 3.1 d apart are very likely due to the same spot. We measure its change in position and determine a rotation period for the host star of 18.6 ± 1.5 d, in good agreement with a published measurement from spot-induced brightness modulation, and a sky-projected orbital obliquity of λ = 6 ± 11°. We conclude with a compilation of obliquity measurements from spot-tracking analyses and a discussion of this technique in the study of the orbital configurations of hot Jupiters
The Size, Shape, Albedo, Density, and Atmospheric Limit of Transneptunian Object (50000) Quaoar from Multi-chord Stellar Occultations
We present results derived from the first multi-chord stellar occultations by the transneptunian object (50000) Quaoar, observed on 2011 May 4 and 2012 February 17, and from a single-chord occultation observed on 2012 October 15. If the timing of the five chords obtained in 2011 were correct, then Quaoar would possess topographic features (crater or mountain) that would be too large for a body of this mass. An alternative model consists in applying time shifts to some chords to account for possible timing errors. Satisfactory elliptical fits to the chords are then possible, yielding an equivalent radius R [SUB]equiv[/SUB] = 555 ± 2.5 km and geometric visual albedo p[SUB]V[/SUB] = 0.109 ± 0.007. Assuming that Quaoar is a Maclaurin spheroid with an indeterminate polar aspect angle, we derive a true oblateness of \epsilon = 0.087^{+0.0268}_{-0.0175}, an equatorial radius of 569^{+24}_{-17} km, and a density of 1.99 ± 0.46 g cm[SUP]–3[/SUP]. The orientation of our preferred solution in the plane of the sky implies that Quaoar's satellite Weywot cannot have an equatorial orbit. Finally, we detect no global atmosphere around Quaoar, considering a pressure upper limit of about 20 nbar for a pure methane atmosphere.Peer reviewe
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