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Slovensky

PhD study at the Astronomical Institute

The Astronomical Institute organizes PhD study in astronomy and astrophysics.

Application deadline: May 15th 2019
Address: Astronomicky ustav SAV
059 60 Tatranska Lomnica
Interviews: end of June 2019
PhD study (start): September 1st 2019
  1. Interstellar particles in the Solar system's interplanetary medium
    Adviser: RNDr. Mária Hajduková Jr., PhD. (Maria.Hajdukova@savba.sk)
    Affiliation: Astronomical Institute of the Slovak Academy of Sciences, The Department of Interplanetary Matter, Bratislava
    Syllabus
        Focus of the research: The interaction of our Solar system with the interstellar medium, due to the motion of the Sun relative to the local interstellar cloud, should lead to the presence of interstellar particles, or, at least, interstellar dust grains. Viewed from within the Solar system, a flow of interstellar matter should be observed. Since identifying particles of interstellar origin is a challenge, the true abundance of interstellar particles in the Solar system has not yet been unambiguously determined.
        Objectives: The aim of this work is to map the influx of the interstellar particles and follow their trajectories through the Solar system. These are influenced by their interaction with the interplanetary medium and controlled by a number of size-dependent forces. The emphasis of this work lies on large particles approaching the Earth's orbit on hyperbolic orbits with respect to the Sun, which can be observed as meteors.
    Computer simulations of interstellar particles' trajectories will be compared with observational data from the avaliable meteor databases. The substantial question is the ratio of the interstellar particles to those belonging to the interplanetary medium, which we should register in a particular region. This depends on the distance from both the Sun and the ecliptic. Therefore, the results of Earth-based and space-born observations will be synthesized to achieve a broader view.
    Requirements:
    programming, the English language
    Research heading:
    The dynamical evolution of the small bodies of the Solar system
  2. Gas emissions in the spectra of distant comets
    Supervisor: Mgr. Oleksandra Ivanova (oivanova@astro.sk)
    Affiliation: Astronomical Institute of the Slovak Academy of Sciences, The Department of Interplanetary Matter, Tatranska Lomnica
    Syllabus
        Focus of the research: Searching for gas emissions in spectra of distant comets responsible for tail formation, mechanism of formation and ionization, analysis of energy distribution in the continuous spectrum to study the physical properties of dust.
        Methods: The study of small bodies that have a cometary activity at a large heliocentric distances (larger than 5 AU) is important for a better understanding of the physical properties of comets and their origin. Using long-slit spectroscopy data of selected distant comets to search for gas emissions. Estimation of upper gas production rates limits for major neutral molecules in cometary comae. Measuring the reddening effect in cometary spectra. Building the surface profile of the cometary coma measured along the direction normal to the slit. Estimation of dust production rate as a function of wavelength.
    Requirements:
    knowledge of English language, good background in physics, basic knowledge in programing (IDL), ability to work independently with literature.
    Research field:
    Structure of meteoroid streams and complexes of small bodies of the Solar System, evolution and physical characteristics of the parent bodies of meteoroids.
  3. Polarimetric characteristics of comets with a perihelion distance of 2 to 3 AU
    Supervisor: Mgr. Oleksandra Ivanova (oivanova@astro.sk)
    Affiliation: Astronomical Institute of the Slovak Academy of Sciences, The Department of Interplanetary Matter, Tatranska Lomnica
    Syllabus
        Focus of the research: Comets play a key role in planetary science because they preserve pristine refractory materials and ices since the moment of the Solar System formation. The vast majority of comets are not available for study by space probes and astronomical observations on visible (sunlight scattered by cometary dust and gaseous emissions) and medium infrared (thermal emissions) areas are the primary source of information on their physical and chemical properties. At the moment, such observations and their consequent analysis are conducted separately from each other.
        Methods: Searching interrelation between polarization and colour of comets in the visible range. Studying the characheristics of sunlight scattered by coma in visible (phase function, spectrum, color, and the degree of linear polarization) allows to retrieve the physical and chemical properties of cometary dust. This work is aimed to investigate the relationship between light-scattering characteristics (phase function, colour, degree of linear polarization) and thermal-emission characteristics (temperature of dust particles and 10-um silicates) of selected comets that are active at heliocentric distances from 2 to 3 AU. The results of this study allow us on interrelation between light-scattering characteristics and thermal emission of cometary dust and, developing of a comprehensive model of cometary dust for comets with low gas emissions.
    Requirements:
    knowledge of English language, good background in physics, basic knowledge in programing (IDL), ability to work independently with literature.
    Research field:
    Structure of meteoroid streams and complexes of small bodies of the Solar System, evolution and physical characteristics of the parent bodies of meteoroids.
  4. Short-term color changes in comets at large heliocentric distances
    Supervisor: Mgr. Oleksandra Ivanova (oivanova@astro.sk)
    Affiliation: Astronomical Institute of the Slovak Academy of Sciences, The Department of Interplanetary Matter, Tatranska Lomnica
    Syllabus
        Focus of the research: Microphysical properties of dust particles in the vast majority of comets can be deduced only using remote-sensing techniques based on the interaction of dust with solar radiation. Such interaction is manifested in three sets of phenomena: the elastic scattering of the sunlight in visible and near-IR bands, thermal emission of the absorbed solar radiation in mid-IR, and the radiation pressure that affects the motion of dust particles and, their spatial distribution in the coma and tail.
    Photometric colour of dust particles is defined as the ratio of scattered-radiation fluxes measured at two different wavelengths. Its strength lies in the relative nature as it depends directly on the microphysical properties of the dust particles, and it is independent of their number within the field of view. This is important because it is known that the number of dust particles forming a cometary coma is a subject to rapid and significant variations.
    Main goal of the work is using long-lasting observations of selected distant comets searching for variations of its colour. Detecting of fast changes in colour of distant comets provides important clues for better understanding of the microphysical properties of its dust.
        Methods: Photometry with broadband filters of selected distant comets. Studying fast variations of the color index in selected distant comets, searching for the frequency of occurrence of this phenomenon in various comets, its interrelation with other features of comets. Building the color maps of the comets. The use of the spectrum will provide exhaustive information on the presence of gaseous emissions in comets, which makes it very possible to derive the colour of cometary dust.
    Requirements:
    knowledge of English language, good background in physics, basic knowledge in programing (IDL), ability to work independently with literature.
    Research field:
    Structure of meteoroid streams and complexes of small bodies of the Solar System, evolution and physical characteristics of the parent bodies of meteoroids.
  5. Solar activity cycles - empirical implications for the solar dynamo modelling
    Adviser: RNDr. Ján Rybák, CSc. (choc@astro.sk)
    Affiliation: Astronomical Institute of the Slovak Academy of Sciences, The Department of Solar Physics, Tatranska Lomnica
    Syllabus
    An analysis of the long-term observations of the solar activity - sunspots, magnetic fields as well as measurements of prominences and green corona - for determination of behaviour and importance of manifestations of different activity separately on individual hemispheres of the Sun with searching for empirical implications for modelling of the solar activity by numerical methods describing the solar dynamo. An expected output of the research is determination of the temporal evolution of the time-latitude asymmetry of the solar activity for time period of several solar activity cycles and an analysis of its importance for different periods together with searching for probable periodicities of the activity.
    Requirements:
    English language, programming skills, physical background
    Research heading:
    Research of physical properties and processes in the atmosphere of the Sun

For further information, please contact supervisors via email...


In Tatranska Lomnica, February 20th, 2019

Mgr. Martin Vaňko, PhD.
Director of the AISAS

Requirements

Programme: ASTRONOMY AND ASTROPHYSICS

Joint commission

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Date and Time: 21.9. 2019 06:51:39 CEST
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