Kajatkari, Perttu
M.Sc.-thesis: ULX M82 X-1: spectral and lightcurve analysis; 2007; University of Helsinki, Department of Astronomy
Mynttinen, Johanna
M.Sc.-thesis: GRS 1015+105: a spectral study of different classes observed with INTE-GRAL; 2007; University of Helsinki, Department of Astronomy
Savolainen, Petri
M.Sc.-thesis: Modelling the X-ray spectrum of the neutron star LMXB GX 9+9; 2007; University of Helsinki, Department of Astronomy
Uunila, Minttu
M.Sc.-thesis: Investigations of particle detec-tion capability of the XSM om SMART-1; 2007;
University of Helsinki, Department of Astronomy
3.6 Visits abroad
Hannikainen, Diana
University of Sydney, School of Physics, Aus-tralia, 27.2.–22.3.2007, 23 days
University of Grenoble, Laboratoire d’Astrophysique de l’Observatoire de Greno-ble, France, 25.–27.4.2007, 3 days
Southampton, Department of Physics and As-tronomy, U.K., 10.–13.5.2007, 4 days
ESO, Germany, 21.–24.5.2007, 4 days
Laboratori Nazionali di Frascati, INAF, Italy, 27.5.–3.6.2007, 8 days
Physikalisches Institut, Friedrich-Alexander-Universit¨at, Germany, 22.–26.7.2007, 5 days
Yerevan State University, Armenia, 19.–
25.8.2007, 7 days
Service d’Astrophysique, CEA Saclay, France, 20.–27.9.2007, 8 days
INAF – Istituto di astrofisica spaziale e fisica cosmica, Italy, 16.–19.10.2007, 4 days
Mullard Space Science Laboratory, UCL, U.K., 24.–27.10.2007, 4 days
University of Florida, USA, 27.10.–2.11.2007, 7 days
ESO, Germany, 19.–2.11.2007, 4 days
Huovelin, Juhani
XLI Annual Conference of the Finnish Physi-cal Society, 15.–17.3.2007, Tallinn, Estonia, 3 days BepiColombo SIXS ISRR meeting, ESTEC;
Noordwijk, The Netherlands, 14.–15.5.2007, 2 days ESO-Sampo meeting, Garching, Germany, 31.5.2007, 1 day
BepiColombo SWG meeting, ESTEC, Noord-wijk, The Netherlands, 25.–26.6.2007, 2 days
Meeting with ESO Director General, ESO, Garching, Germany, 16.11.2007, 1 day
Sampo project meeting, ESO, Garching, Ger-many, 7.12.2007, 1 day
BepiColombo SWT4 meeting, Germany, 18.–
19.9.2007, 2 days Maisala, Sami
ESO Reflex workshop; Garching, Germany, 22.–23.1.2007, 2 days
ESO/Sampo meetings, Garching, Germany, 12.–16.3.2007, 5 days
Sampo team meeting, Garching, Germany, 15.–16.5.2007, 2 days
Sampo team meeting; Garching, Germany, 29.5.–1.6.2007, 4 days
ADASS 2007, London, U.K., 23.–28.9.2007, 6 days
Sampo project meeting, ESO, Garching, Ger-many, 6.–8.12.2007, 3 days
Nevalainen, Jukka
University of Heidelberg, Germany, 30.3.–
3.4.2007, 2 days
University of California, LA, USA, 9.–
11.5.2007, 3 days
International Space Science Institute, Switzer-land, 17.–21.6.2007, 5 days
Universit Paris Sud, Orsay, France, 14.–
15.12.2007, 2 days
Meeting at Tartu, Toravere, Estonia, 25.–
28.2.2007, 4 days Oittinen, Tero
VOTech meeting ESO, Garching, Germany, 12.–18.3.2007, 7 days
Sampo Team Meeting; Garching, Germany, 15.–16.5.2007, 2 days
ESO Team Meeting; Garching, Germany, 29.–
31.5.2007, 3 days
ADASS 2007, London, U.K., 23.–28.9.2007, 6 days
TechNet Europe 2007, Sweden, 16.–
18.10.2007, 3 days
Sampo project meeting; ESO, Garching, Ger-many, 6.–8.12.2007, 3 days
Solin, Otto
ESO/Sampo Reflex Workshop, Germany, 22.–
23.1.2007, 2 days
ESO/Sampo project meetings; Garching, Ger-many, 12.–16.3.2007, 5 days
Sampo project visit to ESO headquarters;
Garching, Germany, 6.5.–1.6.2007, 27 days ADASS 2007, London, U.K., 23.–28.9.2007, 6 days
Sampo project meeting; ESO, Garching, Ger-many, 6.–9.12.2007, 4 days
Somero, Auni
3rd Workshop for Nordic Network for Women in Physics, Technical University of Denmark, Den-mark, 14.–19.8.2007, 6 days
Ullgren, Marko
ESO, Germany, 22.–23.1.2007, 2 days
Opticon N3.6 network face-to-face meeting, Tenerife, Spain, 1.–2.3.2007, 2 days
Sampo team meeting, Germany, 30.–
31.5.2007, 2 days V¨a¨an¨anen, Mikko
7th RHESSI Workshop, Santa Cruz, USA, 24.6.–1.7.2007, 12 days
3.7 Papers read at scientific conferences, symposia, meetings etc.
Hannikainen, Diana
”Multifrequency observations of micro-quasars”, Multifrequency Behaviour of High Energy Cosmic Sources, 27.5.–3.6.2007, Vulcano, Italy, invited talk
”X-ray properties of microquasars”, Joint Eu-ropean and National Astronomy Meeting; High Energy Astrophysics: the keV-TeV connection, 19.–25.8.2007, Yerevan, Armenia, invited talk
”GRS 1915+105: Snapshots with INTE-GRAL”, conference A Population Explosion: The nature and evolution of X-ray binaries in diverse
environments, 27.10.–2.11.2007, St. Petersburg, Florida, USA, poster
”Synchrotron flaring behaviour of Cygnus X-3”, A Population Explosion: The nature and evo-lution of X-ray binaries in diverse environments, 27.10.–2.11.2007, St. Petersburg, Florida, USA, poster
”RXTE and INTEGRAL observations of IGR J19140+0951”, A Population Explosion: The na-ture and evolution of X-ray binaries in diverse environments, 27.10.–2.11.2007, St. Petersburg, Florida, USA, poster
Maisala, Sami
”Using ESO Reflex with Web Services”, ADASS XVII, 23.–28.9.2007, London, U.K., poster
”ESO Reflex: A Graphical Workflow Engine for Data Reduction”, ADASS XVII, 23.–28.9.2007, London, U.K., poster
Oittinen, Tero
”Using ESO Reflex with Web Services”, ADASS XVII, 23.–28.9.2007, London, U.K., poster
”ESO Reflex: A Graphical Workflow Engine for Data Reduction”, ADASS XVII, 23.–28.9.2007, London, U.K., poster
Ullgren, Marko
”ESO Reflex: A Graphical Workflow Engine for Data Reduction”, ADASS 2007, 23.–26.9.2007, London, U.K., poster
”Using ESO Reflex with Web Services”, ADASS 2007, 23.–26.9.2007, London, U.K., poster
3.8 Membership in scientific and schol-arly societies
Hannikainen, Diana
International Workshop on Radiation Imaging Detectors, expert
ESO Observing Proposal Committee, May &
November 2007, expert
Huovelin, Juhani
Finnish COSPAR committee, Finland Research school for astronomy and astro-physics, Finland
Tuorla Observatory board, Finland
Academy of Finland assessor pool, Finland, expert
Nevalainen, Jukka
XMM-Newton AO7 Time Allocation Commit-tee, 12.–14.11.2007, U.K., expert
Planck Working Group 5, 30.3.2007–, expert International Astronomical Consortium for High Energy Calibration, 9.5.2007–, expert
3.9 Acting as Opponent and pre-examinations of doctoral disser-tations
Hannikainen, Diana
Clement Cabanac: ”Variabilite temporelle des binairesX: observations avec INTEGRAL. Modeli-sation”, University of Grenoble, 26.4.2007, France, opponent
Fiamma Capitanio, University of Southamp-ton, 11.5.2007, U.K., opponent
3.10 Refereeing and Other Publishing Activities
Hannikainen, Diana
Monthly Notices of the Royal Astronomical Society, March 2007, U.K., referee
Nuclear Instruments and Methods in Physics Research, referee
Huovelin, Juhani
Earth and Planetary Science, Japan, referee Nevalainen, Jukka
Publications of the Astronomical Society of Japan, October 2007, referee
4 Planetary System Research
Project number 02525008
Research agreements Academy of Finland Type of research Basic research
Director of research DocentMuinonen, Karri
Telephone 19122941
Fax 19122952
E-mail Karri.Muinonen@Helsinki.Fi
Research staff with a Ph.D. Karri Muinonen, Docent Kari Lumme, Prof Phd student(s) Mikael Granvik, M.Sc.
Jyri N¨ar¨anen, M.Sc.
Dagmara Oszkiewicz, M.Sc.
Hannu Parviainen, M.Sc.
Antti Penttil¨a, M.Sc.
Jari Rantala, M.Sc.
Johanna Torppa, M.Sc.
Jani Tyynel¨a, M.Sc.
Students Jarkko Niemel¨a
Hannakaisa Erkkil¨a Associated scientists Markku Poutanen, Prof.
Jouni Peltoniemi, Docent Timo Nousiainen, Docent Jenni Virtanen, Ph.D.
4.1 Research activities
Research within the Planetary-System Research -group (PSR) at the University of Helsinki Observatory entails theoretical, observational, and experimental studies on key topics of solar-system exploration. In fundamental planetary physics, PSR theoretical research is focussed on light scattering by single small particles, on multi-ple scattering by commulti-plex media of small particles, and the celestial mechanics of the few-body problem. Ex-periments have been carried out to measure backscatter-ing characteristics of particulate media (scatterometer at the Observatory) and to assess the X-ray fluorescence by planetary-regolith analog samples (at the Department of Physical Sciences). Observations have been made using both space-based and ground-based telescopes.
The numerical method for computing coherent backscattering by complex particulate media developed at UHO has been successfully applied to polarimet-ric observations of transneptunian objects (TNOs). At ESO/VLT, PSR has continued to participate in polari-metric observations of TNOs, for example, through par-ticipation in the Large Program on the physical prop-erties of TNOs. Furthermore, PSR has taken part in polarimetric observations of cometary nuclei at VLT:
these observations are the first-ever systematic polari-metric observations of cometary nuclei and their detailed interpretation is in progress.
Systematic light-scattering simulations have been carried out for Gaussian-random-sphere particles with the Discrete-Dipole Approximation (DDA, Muinonen et al. 2007B1). These simulations have allowed PSR researchers to unveil the single-scattering in-terference mechanisms for the enhanced-intensity and negative-polarization branches of wavelength-scale
scat-terers (Muinonen et al. 2007B1, Tyynel¨a et al. 2007B1).
The mechanisms have been studied in detail for spher-ical particles by concentrating on the properties of the electromagnetic fields inside the scatterers. First steps have been taken to assess the properties of the internal fields of Gaussian particles (Tyynel¨a et al. 2007B2). Fur-thermore, DDA has been utilized to search for coherent-backscattering effects (Penttil¨a and Lumme 2007B2).
Understanding the physical mechanisms of the backscat-tering phenomena is of utmost importance, for example, for remote investigations of the solar system.
Figure 2: Shape model of asteroid (1862) Apollo from two perpendicular equatorial viewing directions.
Lightcurve inversion was performed using the convex in-version method and all the available lightcurve data.
In scattering of light by single small particles, PSR has studied surface-roughness effects using the DDA method and the Gaussian-random-sphere geometry, fo-cusing on both harmonic roughness and what can be called ”ragged” roughness (Nousiainen and Muinonen 2007B1, Zubko et al. 2007B1). Scattering by thin ir-regularly undulating films has also been studied using DDA (Parviainen and Lumme 2007B2). PSR has
de-veloped a possible way to generate concave hulls on concave shapes, with application to light scattering by concave-hull-transformed Gaussian particles (Muinonen and Erkkil¨a 2007B2). In scattering of light by particu-late media, surface-roughness effects are being incorpo-rated into both scattering and X-ray fluorescence mod-els for planetary regoliths using fractional-Brownian-motion surfaces and size distributions of spherical parti-cles (Parviainen and Muinonen 2007B1, N¨ar¨anen et al.
2007B2a, N¨ar¨anen et al. 2007B2b).
Figure 3: Possible spin-axis directions of asteroid (31) Euphrosyne. Lightcurve inversion was performed us-ing the convex inversion method and all the available lightcurve data.
Detailed comparisons have been carried out between different DDA codes (Penttil¨a et al. 2007B1). Radar backscattering by shoots of scots pines have been studied using DDA (Manninen et al. 2007B1). As light scatter-ing has also direct applications in industrial processes, PSR has continued to model some industrial products like paper coatings for ideal light scattering. One of the purposes is to improve the quality of paper.
PSR has continued studies of light scattering by large irregular Saharan sand particles, via Gaussian-random-sphere modelling for their shapes and assessing the significance of surface-roughness effects on scatter-ing (Munoz et al. 2007B1, Munoz et al. 2007B2). Light scattering by such particles has been revisited both ex-perimentally and theoretically: particle scattering char-acteristics are seen to be dictated by small-scale surface roughness.
In the field of asteroid orbital inversion using statis-tical methods, PSR has succeeded in finalizing orbital inverse methods for arbitrary numbers of observations and arbitrary observational time intervals. Recent de-velopments include, e.g., the n-body statistical ranging (Granvik and Muinonen 2007B2).
Figure 4: The layout of the goniometric laboratory setup used to study the regolith effects on X-ray fluorescence spectroscopy. Both emergence and incidence angles can be varied to simulate realistic observation geometries from orbiting spacecraft, e.g. ESA BepiColombo mission to Mercury. The measurements need to be performed in vacuum since air in NTP conditions is an efficient ab-sorber and scatterer of soft X-rays.
PSR has assessed the asteroid identification problem at discovery as well as across multiple apparitions and derived efficient loglinear identification methods based on augmented red-black binary trees and dimensionality-reduction techniques (Granvik 2007A1, Granvik et al.
Figure 5: An image of the goniometric laboratory setup used to study the regolith effects on X-ray fluorescence spectroscopy. Both emergence and incidence angles can be varied to simulate realistic observation geometries from orbiting spacecraft, e.g., ESA BepiColombo mission to Mercury. The measurements need to be performed in vacuum since air in NTP conditions is an efficient ab-sorber and scatterer of soft X-rays.
2007B1). The new identification methods have been successfully applied, first, to observational data ob-tained nearly simultaneously with the ESO/VLT (Very Large Telescope) and CFHT (Canada-France-Hawaii Telescope) groundbased telescopes as well as the Spitzer space observatory (Granvik et al. 2007B1) and, second, to single-apparition observational data collected during the last hundred years or so (Granvik and Muinonen 2007B2). Granvik et al. (2007) successfully applied the short-term identification method to astrometric observa-tions obtained nearly-simultaneously with the Canada-France-Hawaii Telescope, ESO’s Very Large Telescope, and the Spitzer space telescope. In addition to solv-ing the nontrivial identification problem, they derived an empirical rule-of-thumb for the decrease in orbital-element uncertainty obtained via stereoscopic observa-tions as compared to a single-telescope approach.
Figure 6: Typical soft X-ray fluorescence spectrum of olivine basalt (lunar mare regolith analog), as measured with the soft X-ray spectrogoniometer. The sample is excited by a Titanium anode X-ray tube, and the en-ergy range in this spectrum is 3.1-8.0 keV. The crosses are the measured spectrum and the line is the empirical multiple-Gaussian model, which fits well all the mea-surable elemental fluorescence emission lines from the sample.
Lightcurve inversion for asteroid spins and shapes has progressed steadily using the convex inversion meth-ods (Torppa 2007A1). At the Nordic Optical Tele-scope (NOT), PSR has coordinated a major Nordic NEON (Near-Earth-Object Network) photometric and astrometric observing program on near-Earth objects (NEOs). The observations have been interpreted using statistical convex-inversion techniques as well as analyti-cal techniques using simple shape models such as sphere-cylinders (Muinonen et al. 2007B2). As an important
Figure 7: A scanning-electron-microscope image of olivine basalt sample with particle-size range of 75-250 micrometers. This sample is considered to be a good analog material for lunar mare regoliths and has been used by PSR in laboratory investigations of viewing-geometry-dependent effects in both visible and soft X-ray wavelengths. The scale bar in the bottom left corner of the image indicates a length of 200 micrometers in the image.
step toward statistical asteroid spin and shape inversion methods, a downhill simplex inversion method has been established for general convex shape models (Muinonen and Torppa 2007B2). PSR participation in observing programs has resulted in publication of NEO astromet-ric positions (Muinonen et al. 2007B3a and 2007B3b) as well as Minor Planet Electronic Circular (MPEC) on comet 19P/Borrelly (Bagnulo et al. 2007B3).
PSR is actively participating in the interpretation of the AMIE camera observations of the Moon (Josset et al. 2007B2). SMART-1 was launched in 2003 and the mission ended with an impact of the spacecraft on the lu-nar surface in 2006. During the extended mission phase, upon request by PSR, AMIE observations of the Moon were carried out close to opposition geometries. The calibration of the AMIE image data started in late 2007, providing good prospects for quantitative interpretation of the extensive lunar image data (more than 100 000 images taken).
PSR is a key participant in the BepiColombo mission to Mercury (launch in 2013): Mercury Imaging X-ray Spectrometer MIXS (UK PI, Finnish Co-PI) will carry out a global elemental and surface-structural mapping of Mercury, whereas the Solar Intensity X-ray and particle Spectrometer SIXS (Finnish PI, UK Co-PI) will provide the simultaneous calibration observations of the flux of radiation and particles. In preparation for BepiColombo,
X-ray fluorescence measurements have been carried out at the University of Helsinki and at the University of Le-icester, accompanied by qualitative interpretation with quantitative interpretation in progress (N¨ar¨anen et al.
2007B2a, N¨ar¨anen et al. 2007B2b).
For the ESA Gaia mission (launch in 2012), PSR is managing and preparing the orbital-inversion work pack-age, entailing the full solution of the orbital inverse prob-lems for asteroids and comets. PSR has continued to participate in the NEOSSat/NESS space project (Hilde-brand et al. 2007B2). Involvement of PSR in the ac-tivities of the International Astronomical Union (IAU) has resulted in PSR participation in the review reports of IAU Division I & III Working Group on Near-Earth Objects (Morrison et al. 2007B3), Division III Commis-sion 15 (Tedesco et al. 2007B3), as well as DiviCommis-sion III Commission 20 (Valsecchi et al. 2007B3).
4.2 External financing and resources
2007: Man-months of work: 100
Academy of Finland, ’Mercury, Lunar and So-lar Science with BepiColombo and SMART-1: X-ray fluorescence from small-particle media’:
42 800 e
European Commission, ’European Leadership in Space Astrometry’ (ELSA)’: 34 000e
4.3 Visits abroad
Granvik, Mikael
Gaia CU4 workshop, Paris, France, 15.–
17.2.2007, 3 days
Gaia DPAC CU4 workshop, Nizza, France, 9.–
12.5.2007, 4 days
ELSA School on the Science of Gaia, Leiden, The Netherlands, 19.–29.11.2007, 11 days
DPS 2007 meeting, Orlando, Florida, USA, 6.–12.10.2007, 7 days
Lumme, Kari
DDA-workshop, Bremen, Germany, 22.–
25.3.2007, 4 days Muinonen, Karri
CNES Toulouse, France, 23.–28.4.2007, 6 days Observatoire de la Cote d’Azur, Nizza, France, 9.–12.5.2007, 4 days
Light Scattering by Nonspherical Particles meeting, Bodrum, Turkey, 12.–26.6.2007, 14 days
Division for Planetary Sciences meeting, Or-lando, USA, 10.–14.10.2007, 8 days
Observatoire de Paris, France, 11.–14.11.2007, 4 days
University of Leiden, Lorentz Center, ELSA School on the Science of Gaia, The Netherlands, 19.11.–28.11.2007, 10 days
Observatoire de Paris, France, 29.11.–
1.12.2007, 3 days
Observatoire de Paris, France, 16.–17.12.2007, 2 days
N¨ar¨anen, Jyri
ESTEC, The Netherlands, 7.–8.2.2007, 2 days Space Research Center, University of Leices-ter, U.K., 12.–16.3.2007, 5 days
Space Research Center, University of Leices-ter, U.K., 29.10.–7.12.2007, 40 days
EGU General Assembly 2007, Wien, Austria, 17.–22.4.2007, 6 days
BepiColombo SWG ja SOWG meetings, ES-TEC, The Netherlands, 25.–27.6.2007, 3 days
39th Annual DPS Meeting Orlando, Florida, USA, 6.–14.10.2007, 9 days
BepiColombo SWT4, Berlin, Germany, 17.–
19.9.2007, 3 days Oszkiewicz, Dagmara
Paris Observatory, France, 11.–14.11.2007, 4 days
Lorentz Center, The Netherlands, 18.–
28.11.2007, 10 days Parviainen, Hannu
University of Leicester, U.K., 19.5.–18.7.2007, 62 days
Penttil¨a, Antti
DDA-workshop, Bremen, Germany, 22.-25.3.2007, 4 days
Torppa, Johanna
American Astronomica Society, Division of Planetary Systems, USA, 6.–13.10.2007, 8 days Tyynel¨a, Jani
10th Electromagnetic and light scattering con-ference, Turkey, 17.–23.6.2007, 6 days
ADASS 2007, London, U.K., 23.–26.9.2007, 4 days
4.4 Papers read at scientific conferences, symposia, meetings etc.
Granvik, Mikael
”Three-dimensional solar system with Gaia:
asteroid orbits, rotation periods, spins, and shapes”, ELSA School on the Science of Gaia, 19.–
29.11.2007, Leiden, The Netherlands, poster
”Asteroid identification at discovery and over apparitions”, DPS 2007, 7.–12.10.2007, Orlando, Florida, USA
Muinonen, Karri
”On asteroid impact risk analysis using short-arc data”, European Geosciences Union, Gen-eral Assembly 2007, 15.–20.4.2007, Wien, Austria, poster
”X-ray spectroscopy of solar-system regoliths:
theoretical and empirical studies”, European Geo-sciences Union, General Assembly 2007, 15.–
20.4.2007, Wien, Austria
”Scattering of light by concave-hull-transformed Gaussian particles”, Tenth Con-ference on Electromagnetic & Light Scattering, 17.–22.6.2007, Bodrum, Turkey
”Simplex inversion of asteroid photometric lightcurves”, Tenth Conference on Electromag-netic & Light Scattering, 17.–22.6.2007, Bodrum, Turkey
”The scattering matrix of large Libyan desert particles”, Tenth Conference on Electromagnetic &
Light Scattering, 17.–22.6.2007, Bodrum, Turkey, poster
”Soft X-ray spectroscopy at small to medium phase angles: theoretical amd empirical studies”, Tenth Conference on Electromagnetic & Light Scattering, 17.–22.6.2007, Bodrum, Turkey, poster
”Interrelating angular scattering characteris-tics to internal electric fields of wavelength-scale Gaussian particles”, Tenth Conference on Electro-magnetic & Light Scattering, 17.–22.6.2007, Bo-drum, Turkey
”Single-scattering mechanism for asteroid negative polarization and opposition brightening”, The XI Meeting of Finnish National COSPAR (FinCOSPAR), 4.–5.10.2007, Espoo, Finland
”Linking scarce asteroid astrometry at dis-covery and over apparitions”, The XI Meeting of Finnish National COSPAR (FinCOSPAR), 4.–
5.10.2007, Espoo, Finland
”Asteroid orbits from Markov-Chain Monte-Carlo ranging”, The XI Meeting of Finnish Na-tional COSPAR (FinCOSPAR), 4.–5.10.2007, Es-poo, Finland, poster
”Planetary soft X-ray spectroscopy: effects of regolith properties”, The XI Meeting of Finnish National COSPAR (FinCOSPAR), 4.–5.10.2007, Espoo, Finland, poster
”Asteroidien muotojen luonnehdinta ja tiikka (Asteroid shape characterization and statis-tics)”, The XI Meeting of Finnish National COSPAR (FinCOSPAR), 4.–5.10.2007, Espoo, Finland
”Single-scattering mechanism for negative po-larization and opposition brightening of atmo-sphereless solar-system objects”, 39th Division for Planetary Sciences Meeting (DPS), 8.–12.10.2006, Orlando, Florida, USA
”Planetary soft X-ray spectroscopy: studies on the effects of regolith properties”, 39th Divi-sion for Planetary Sciences Meeting (DPS), 8.–
12.10.2006, Orlando, Florida, Finland
”Characterization of asteroid shapes”, 39th Division for Planetary Sciences Meeting (DPS), 8.–
12.10.2006, Orlando, Florida, USA, poster
”Characterization of TNOs’ surface proper-ties: preliminary results of a large VLT pro-gramme”, 39th Division for Planetary Sciences Meeting (DPS), 8.–12.10.2006, Orlando, Florida, USA
”Linking scarce asteroid astrometry at discov-ery and over apparitions”, 39th Division for Plan-etary Sciences Meeting (DPS, 8.–12.10.2006, Or-lando, Florida, USA
”ELSA – Training the next generation of space astrometrists”, IAU Symposium 248 A Giant Step:
from milli- to micro-arcsecond astrometry, 15.–
19.10.2007, Shanghai, Kiina, poster
”The composition of organics in cometary dust constrained by light-scattering properties of agglomerated dust particles”, Japan Society for the Promotion of Science Meeting, Japan
”SMART-1 / AMIE camera results”, Lunar and Planetary Science XXXVIII, 12.–16.3.2007, Houston, Texas, USA
”The Near Earth Object Surveillance Satel-lite (NEOSSAT) mission enables an efficient space-based survey (NESS project) of Interior-to-Earth-Orbit (IEO) asteroids”, Lunar and Planetary Sci-ence XXXVIII, 12.–16.3.2007, Houston, Texas, USA
N¨ar¨anen, Jyri
”X-ray fluorescence and scattering from solar-system regoliths: Theoretical and empirical stud-ies”, EGU General Assembly 2007, 17.–22.4.2007,
”X-ray fluorescence and scattering from solar-system regoliths: Theoretical and empirical stud-ies”, EGU General Assembly 2007, 17.–22.4.2007,