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See detailOn-Orbit Degradation of Solar Instruments
BenMoussa, A.; Gissot, S.; Schühle, U. et al

in Solar Physics (2013)

We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that ... [more ▼]

We present the lessons learned about the degradation observed in several space solar missions, based on contributions at the Workshop about On-Orbit Degradation of Solar and Space Weather Instruments that took place at the Solar Terrestrial Centre of Excellence (Royal Observatory of Belgium) in Brussels on 3 May 2012. The aim of this workshop was to open discussions related to the degradation observed in Sun-observing instruments exposed to the effects of the space environment. This article summarizes the various lessons learned and offers recommendations to reduce or correct expected degradation with the goal of increasing the useful lifespan of future and ongoing space missions. [less ▲]

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See detailThe DynaMICCS perspective. A mission for a complete and continuous view of the Sun dedicated to magnetism, space weather and space climate
Turck-Chièze, S.; Lamy, P.; Carr, C. et al

in Experimental Astronomy (2009), 23

The DynaMICCS mission is designed to probe and understand the dynamics of crucial regions of the Sun that determine solar variability, including the previously unexplored inner core, the radiative ... [more ▼]

The DynaMICCS mission is designed to probe and understand the dynamics of crucial regions of the Sun that determine solar variability, including the previously unexplored inner core, the radiative/convective zone interface layers, the photosphere/chromosphere layers and the low corona. The mission delivers data and knowledge that no other known mission provides for understanding space weather and space climate and for advancing stellar physics (internal dynamics) and fundamental physics (neutrino properties, atomic physics, gravitational moments...). The science objectives are achieved using Doppler and magnetic measurements of the solar surface, helioseismic and coronographic measurements, solar irradiance at different wavelengths and in-situ measurements of plasma/energetic particles/magnetic fields. The DynaMICCS payload uses an original concept studied by Thalès Alenia Space in the framework of the CNES call for formation flying missions: an external occultation of the solar light is obtained by putting an occulter spacecraft 150 m (or more) in front of a second spacecraft. The occulter spacecraft, a LEO platform of the mini sat class, e.g. PROTEUS, type carries the helioseismic and irradiance instruments and the formation flying technologies. The latter spacecraft of the same type carries a visible and infrared coronagraph for a unique observation of the solar corona and instrumentation for the study of the solar wind and imagers. This mission must guarantee long (one 11-year solar cycle) and continuous observations (duty cycle > 94%) of signals that can be very weak (the gravity mode detection supposes the measurement of velocity smaller than 1 mm/s). This assumes no interruption in observation and very stable thermal conditions. The preferred orbit therefore is the L1 orbit, which fits these requirements very well and is also an attractive environment for the spacecraft due to its low radiation and low perturbation (solar pressure) environment. This mission is secured by instrumental R and D activities during the present and coming years. Some prototypes of different instruments are already built (GOLFNG, SDM) and the performances will be checked before launch on the ground or in space through planned missions of CNES and PROBA ESA missions (PICARD, LYRA, maybe ASPIICS). [less ▲]

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See detailXMM-Newton Studies of the Wolf-Rayet Colliding-Wind Binaries WR 25 (WN6h+O4f) and WR 11 (WC8+O7.5III)
van der Hucht, K. A.; Raassen, A. J. J.; Mewe, R. et al

in Massive Stars in Interactive Binaries (2007)

We report the analysis of high- and medium-resolution X-ray spectra of the Wolf-Rayet (WR) objects WR25 (HD93162, WN6h+O4f) and WR11 (gamma[SUP]2[/SUP] Velorum, WC8+O7.5III, P =78.53 d), obtained with the ... [more ▼]

We report the analysis of high- and medium-resolution X-ray spectra of the Wolf-Rayet (WR) objects WR25 (HD93162, WN6h+O4f) and WR11 (gamma[SUP]2[/SUP] Velorum, WC8+O7.5III, P =78.53 d), obtained with the reflection grating spectrometers (rgs) and the european photon imaging cameras (epicmos and <small>PN</small>) <small>CCD</small> spectrometers on board the XMM-Newton satellite. [less ▲]

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See detailPerformance of diamond detectors for VUV applications
BenMoussa, A.; Theissen, A.; Scholze, F. et al

in Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment (2006), 568(1), 398-405

We report on experimental results with photodetectors made of diamond. the Large Yield Radiometer (LYRA), will use such detectors for the first time for a solar physics space instrument. A (LYRA) set of ... [more ▼]

We report on experimental results with photodetectors made of diamond. the Large Yield Radiometer (LYRA), will use such detectors for the first time for a solar physics space instrument. A (LYRA) set of measurement campaigns was carried out to obtain their XUV-to-VIS characterization (responsivity, linearity, stability, homogeneity). The responsivity has been measured from the XUV to the NIR, in the wavelength range 1-1127 nm (i.e. 1240-1.1 eV). The diamond detectors exhibit a photoresponse varying in the 40-75 mA/W range at 7 nm and demonstrate a visible rejection ratio (200 versus 500 nm) larger than four orders of magnitude. We show that diamond photodetectors are sensitive sensors for VUV photons, stable within a few percent, with a good linearity and moderate homogeneity. © 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailLYRA, a solar UV radiometer on PROBA2
Hochedez; Schmutz, W.; Stockman, Yvan ULg et al

in Advances in Space Research (2006), 37

LYRA is the solar UV radiometer that will embark in 2006 onboard Proba2, a technologically oriented ESA micro-mission. LYRA is designed and manufactured by a Belgian–Swiss–German consortium (ROB, PMOD/WRC ... [more ▼]

LYRA is the solar UV radiometer that will embark in 2006 onboard Proba2, a technologically oriented ESA micro-mission. LYRA is designed and manufactured by a Belgian–Swiss–German consortium (ROB, PMOD/WRC, IMOMEC, CSL, MPS and BISA) with additional international collaborations. It will monitor the solar irradiance in four UV passbands. They have been chosen for their relevance to Solar Physics, Aeronomy and Space Weather: (1) the 115–125 nm Lyman-a channel, (2) the 200–220 nm Herzberg continuum range, (3) the Aluminium filter channel (17–70 nm) including He II at 30.4 nm and (4) the Zirconium filter channel (1–20 nm). The radiometric calibration will be traceable to synchrotron source standards (PTB and NIST). The stability will be monitored by onboard calibration sources (LEDs), which allow to distinguish between potential degradations of the detectors and filters. Additionally, a redundancy strategy maximizes the accuracy and the stability of the measurements. LYRA will benefit from wide bandgap detectors based on diamond: it will be the first space assessment of a pioneering UV detectors program. Diamond sensors make the instruments radiation-hard and solar-blind: their high bandgap energy makes them insensitive to visible light and, therefore, make dispensable visible light blocking filters, which seriously attenuate the desired ultraviolet signal. Their elimination augments the effective area and hence the signal-to-noise, therefore increasing the precision and the cadence. The SWAP EUV imaging telescope will operate next to LYRA on Proba2. Together, they will establish a high performance solar monitor for operational space weather nowcasting and research. LYRA demonstrates technologies important for future missions such as the ESA Solar Orbiter [less ▲]

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See detailXMM-Newton high-resolution X-ray spectroscopy of the Wolf-Rayet object WR 25 in the Carina OB1 association
Raassen, A. J. J.; van der Hucht, K. A.; Mewe, R. et al

in Astronomy and Astrophysics (2003), 402(2), 653-666

We report the analysis of the first high-resolution X-ray spectra of the Wolf-Rayet (WR) object WR25 (HD 93162, WN6ha+O4f) obtained with the reflection Grating spectrometers (RGS) and the European photon ... [more ▼]

We report the analysis of the first high-resolution X-ray spectra of the Wolf-Rayet (WR) object WR25 (HD 93162, WN6ha+O4f) obtained with the reflection Grating spectrometers (RGS) and the European photon imaging cameras (EPIC-MOS and PN) CCD spectrometers on board the XMM-Newton satellite. The spectrum exhibits bright emission lines of the H- and He-like ions of Ne, Mg, Si and S, as well as Fe XVIII to Fe XX and Fe XXV lines. Line fluxes have been measured. The RGS and e pi c spectra have been simultaneously fitted to obtain self-consistent temperatures, emission measures, and elemental abundances. Strong absorption by the dense WR stellar wind and the interstellar medium (ISM) is observed equivalent to N-H = 7x10(21) cm(-2). Multi-temperature (DEM) fitting yields two dominant components around temperatures of 7.0 and 32 MK, respectively. The XMM intrinsic (i.e. unabsorbed, corrected for the stellar wind absorption and the absorption of ISM) X-ray luminosity of WR25 is L-x(0.5-10 keV) = 1.3x10(34) erg s(-1), and L-x(0.5-10 keV) = 0.85 x 10(34) erg s(-1), (when correcting for the ISM only) assuming d = 3.24 kpc. The obtained chemical abundances are subsolar, except for S. This may be real, but could equally well be due to a weak coupling to the continuum, which is strongly influenced by the absorption column density and the subtracted background. The expected high N-abundance, as observed in the optical wavelength region, could not be confirmed due to the strong wind absorption, blocking out its spectral signature. The presence of the Fe XXV emission-line complex at similar to6.7 keV is argued as being indicative for colliding winds inside a WR+O binary system. [less ▲]

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See detailXMM-Newton high-resolution X-ray spectroscopy of the Wolf-Rayet object WR25 (WN6ha+O4f)
Raassen, A. J. J.; van der Hucht, K. A.; Mewe, R. et al

in Advances in Space Research (2003), 32(6), 1161-1165

We report the analysis of the X-ray spectrum of the Wolf-Rayet star WR 25, observed by RGS and EPIC-MOS on board XMM-Newton. Temperatures up to 40 MK have been determined. Strong absorption, exceeding the ... [more ▼]

We report the analysis of the X-ray spectrum of the Wolf-Rayet star WR 25, observed by RGS and EPIC-MOS on board XMM-Newton. Temperatures up to 40 MK have been determined. Strong absorption, exceeding the value due to the Inter Stellar Medium (ISM) has been detected and assigned to the dense stellar wind. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved. [less ▲]

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See detailOn the perspectives of using XMM to study fundamental parameters of early-type stars
Rauw, Grégor ULg; van der Hucht, K. A.; Mewe, R. et al

in Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies (1999)

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See detailX-Ray Spectroscopy with XMM: A New Powerful Tool to Determine Fundamental Parameters of Early-type Stars
Mewe, R.; Rauw, Grégor ULg; van der Hucht, K. A. et al

(1998)

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