56 citations · 220 across the 13 of their papers we have counts for
13 papers
Extension of Radiative Transfer Coherent Backscattering RT-CB code to dense discrete random media
Johannes Markkanen, Antti Penttilä
The Radiative transfer coherent backscattering (RT-CB) code is extended to apply to dense discrete random media of optically soft spherical particles. This is achieved by utilizing…
Long-lasting activity of asteroid (248370) 2005 QN 173
Oleksandra Ivanova, Javier Licandro, Fernando Moreno +8
We present the results of observations of asteroid (248370) QN obtained during July 2021 - January 2022 with three telescopes. Our analysis revealed the presence of the dus…
On the dust of tailless Oort-cloud comet C/2020 T2 (Palomar)
Yuna Grace Kwon, Joseph R. Masiero, Johannes Markkanen
We report our new analysis of Oort-cloud comet C/2020 T2 (Palomar) (T2) observed at 2.06 au from the Sun (phase angle of 28.5 deg) about two weeks before perihelion. T2 lacks a sig…
Do twin spectral peaks of olivine particles in the thermal infrared diagnose their sizes and porosities?
Hiroshi Kimura, Johannes Markkanen, Ludmilla Kolokolova +4
A well-established constraint on the size of non-porous olivine grains or the porosity of aggregates consisting of small olivine grains from prominent narrow peaks in thermal infra…
VLT spectropolarimetry of comet 67P: Dust environment around the end of its intense Southern summer
Yuna Kwon, Stefano Bagnulo, Johannes Markkanen +5
We report our new spectropolarimetric observations for 67P dust over 4,000--9,000 Angstrom using the ESO/Very Large Telescope in January--March 2016 (phase angle ranging 26--…
An Update of the Correlation between Polarimetric and Thermal Properties of Cometary Dust
Yuna G. Kwon, Ludmilla Kolokolova, Jessica Agarwal +1
We present a possible correlation between the properties of scattered and thermal radiation from dust and the principal dust characteristics responsible for this relationship. To t…
Thermophysical model for icy cometary dust particles
Johannes Markkanen, Jessica Agarwal
Context. Cometary dust particles are subjected to various forces after being lifted off the nucleus. These forces define the dynamics of dust, trajectories, alignment, and fragment…
The dust-to-gas ratio, size distribution, and dust fall-back fraction of comet 67P/Churyumov-Gerasimenko: Inferences from linking the optical and dynamical properties of the inner comae
Raphael Marschall, Johannes Markkanen, Selina-Barbara Gerig +3
In this work, we present results that simultaneously constrain the dust size distribution, dust-to-gas ratio, fraction of dust re-deposition, and total mass production rates for co…
Scattering, absorption, and thermal emission by large cometary dust particles: Synoptic numerical solution
Johannes Markkanen, Jessica Agarwal
Context: Remote light scattering and thermal infrared observations provide clues about the physical properties of cometary and interplanetary dust particles. Identifying these prop…
Interpretation of the phase functions measured by the OSIRIS instrument for Comet 67P/Churyumov-Gerasimenko
Johannes Markkanen, Jessica Agarwal, Timo Väisänen +2
We show that the scattering phase functions of the coma and the nucleus of the comet 67P/Churyumov-Gerasimenko measured by the Rosetta/OSIRIS instrument can be reproduced by a part…
Realization of a spherical boundary by a layer of wave-guiding medium
I. V. Lindell, J. Markkanen, A. Sihvola +1
In this paper the concept of wave-guiding medium, previously introduced for planar structures, is defined for the spherically symmetric case. It is shown that a quarter-wavelength…
Polyphase alternating codes
Markku Markkanen, Juha Vierinen
This work introduces a method for constructing polyphase alternating codes in which the length of a code transmission cycle can be or , where is a prime number and $…
Interstellar Scintillation od Pulsar B0809+74
Barney Rickett, Bill Coles, Jussi Markkanen
Weak interstellar scintillations of pulsar B0809+74 were observed at two epochs using a 30m EISCAT antenna at 933 MHz. These have been used to constrain the spectrum, the distribut…