ESA Science & Technology - Publication Archive
This document provides the top-level science requirements for the Exoplanet Characterisation Observatory (EChO), a dedicated mission to investigate exoplanetary atmospheres. The EChO mission was proposed to ESA in response to the M3 call in ESA's Cosmic Vision programme, and was selected for assessment in February 2011. The mission in turn builds on a concept for an Exoplanet Spectroscopy Mission (ESM) that was recommended by the Exoplanetary RoadMap Advisory Team (EPRAT) in 2009/10 for study by ESA. The science requirements were initially derived from the science objectives described in the EChO M3 proposal and have been refined and updated following discussions between the EChO science team and the ESA internal study team. This document was first written as input to the CDF study starting in June 2011. It has been updated continuously since, and will continue to be refined over the course of the study. The aim of this document is to detail the science requirements for all aspects of the mission. As such, the document provides a means by which to understand, trace and support a detailed analysis of the relationship between the science objectives of the mission and the specification of the mission and payload.
EChO (Exoplanet Characterisation Observatory) is an M-class mission candidate for the M3 slot within the Cosmic Vision programme, for a planned launch between 2022 and 2024. EChO, with 3 other science missions, was recommended by the Space Science Advisory Committee (SSAC) to enter an assessment study (Phase 0), starting by an ESA internal study followed by parallel industrial study activities.
Within the M3 boundary conditions, the readiness for launch by 2022/2024 is a severe requirement which in practice requires designing the space segment without major technology developments and with minimum developments risks. Therefore, only technologies with estimated Technology Readiness Levels (TRL) of at least 5 by the end of the Phase A/B1 (estimated at the end of 2015) may be used.
This document aims at providing a complete and comprehensive list of all high level mission requirements (including spacecraft and payload, launcher, ground segment and operations) necessary to achieve the science goals detailed in [EChO SciRD (Science Requirements Document), SRE-PA/2011.037/]. It is hence an applicable document that all mission design activities shall comply with. The MRD will be further reviewed matching the results of future study phases (e.g. definition phase) to finally evolve in the System Requirements Document at the start of the implementation phase.
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Published online 13 November 2013.
Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. Energetic considerations and circular-polarization measurements have provided conflicting circumstantial evidence for the presence or absence of baryons in jets, and the only system in which they have been unequivocally detected is the peculiar X-ray binary SS 433. Here we report the detection of Doppler-shifted X-ray emission lines from a more typical black-hole candidate X-ray binary, 4U 1630-47, coincident with the reappearance of radio emission from the jets of the source. We argue that these lines arise from baryonic matter in a jet travelling at approximately two-thirds the speed of light, thereby establishing the presence of baryons in the jet. Such baryonic jets are more likely to be powered by the accretion disk than by the spin of the black hole, and if the baryons can be accelerated to relativistic speeds, the jets should be strong sources of gamma-rays and neutrino emission.
Published online 14 August 2013
Soft-gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly rotating, isolated neutron stars that sporadically undergo episodes of long-term flux enhancement (outbursts) generally accompanied by the emission of short bursts of hard X-rays. This behaviour can be understood in the magnetar model, according to which these sources are mainly powered by their own magnetic energy. This is supported by the fact that the magnetic fields inferred from several observed properties of SGRs and AXPs are greater than - or at the high end of the range of - those of radio pulsars. In the peculiar case of SGR 0418+5729, a weak dipole magnetic moment is derived from its timing parameters, whereas a strong field has been proposed to reside in the stellar interior and in multipole components on the surface. Here we show that the X-ray spectrum of SGR 0418+5729 has an absorption line, the properties of which depend strongly on the star's rotational phase. This line is interpreted as a proton cyclotron feature and its energy implies a magnetic field ranging from 2 × 1014 gauss to more than 1015 gauss.