English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

We present an analysis of the photometric and spectroscopic data of the cometC/2012 S1 (ISON) observed at the heliocentric distances of 6.21\div 4.81 AU.The photometric observations were made with the 60-cm Zeiss-600 telescope(ICAMER, peak Terskol, Russia) and the spectroscopic observations wereperformed using the SCORPIO-2 focal reducer mounted in the prime focus of the6-m BTA telescope (SAO RAS, Russia). We analyse the B, V and R-band images todescribe the dusty cometary coma and to investigate its brightness, colours anddust production rate. The spectra cover the wavelength range of 3600\div 7070\AA. No emissions which are expected in this wavelength region were detectedabove the 3$\sigma$ level. The continuum shows a reddening effect with thenormalized gradient of reflectivity along dispersion of (9.3$\pm$1.1)% per 1000\AA. A dust-loss rate was derived using the obtained values and under thedifferent model assumptions. Our simulations clearly indicate that to retrievedust production from the observational Af$\rho$ parameter is an ambiguous task.The result of such a procedure is strongly dependent on dynamical (e.g.effective density and cross-section) as well as optical (e.g. scatteringcoefficient and phase function) characteristics of dust grains. A variation ofthe mentioned parameters can lead to dramatic changes in the evaluation of massproduction. We demonstrate that the dynamic and optical properties areinterconnected via the microscopic properties of dust grains (effective sizeand porosity).

The optical characteristics of the dust of sungrazing comet C/2012 S1 (ISON) observed at large heliocentric distances