Dataset Information

Laboratory unraveling of matter accretion in young stars.

ABSTRACT: Accretion dynamics in the formation of young stars is still a matter of debate because of limitations in observations and modeling. Through scaled laboratory experiments of collimated plasma accretion onto a solid in the presence of a magnetic field, we open a first window on this phenomenon by tracking, with spatial and temporal resolution, the dynamics of the system and simultaneously measuring multiband emissions. We observe in these experiments that matter, upon impact, is ejected laterally from the solid surface and then refocused by the magnetic field toward the incoming stream. This ejected matter forms a plasma shell that envelops the shocked core, reducing escaped x-ray emission. This finding demonstrates one possible structure reconciling current discrepancies between mass accretion rates derived from x-ray and optical observations, respectively.

SUBMITTER: Revet G

PROVIDER: S-EPMC5665592 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Laboratory unraveling of matter accretion in young stars.

Revet Guilhem G Chen Sophia N SN Bonito Rosaria R Khiar Benjamin B Filippov Evgeny E Argiroffi Costanza C Higginson Drew P DP Orlando Salvatore S Béard Jérôme J Blecher Marius M Borghesi Marco M Burdonov Konstantin K Khaghani Dimitri D Naughton Kealan K Pépin Henri H Portugall Oliver O Riquier Raphael R Rodriguez Rafael R Ryazantsev Sergei N SN Yu Skobelev Igor I Soloviev Alexander A Willi Oswald O Pikuz Sergey S Ciardi Andrea A Fuchs Julien J

Science advances 20171101 11

Accretion dynamics in the formation of young stars is still a matter of debate because of limitations in observations and modeling. Through scaled laboratory experiments of collimated plasma accretion onto a solid in the presence of a magnetic field, we open a first window on this phenomenon by tracking, with spatial and temporal resolution, the dynamics of the system and simultaneously measuring multiband emissions. We observe in these experiments that matter, upon impact, is ejected laterally ...[more]

PMID: 29109974

Similar Datasets

Project description:Background and purposeModifications of magnetic susceptibility have been consistently demonstrated in the subcortical gray matter of MS patients, but some uncertainties remain concerning the underlying neurobiological processes and their clinical relevance. We applied quantitative susceptibility mapping and longitudinal relaxation rate relaxometry to clarify the relative contribution of atrophy and iron and myelin changes to deep gray matter damage and disability in MS.Materials and methodsQuantitative susceptibility mapping and longitudinal relaxation rate maps were computed for 91 patients and 55 healthy controls from MR images acquired at 3T. Applying an external model, we estimated iron and myelin concentration maps for all subjects. Subsequently, changes of deep gray matter iron and myelin concentration (atrophy-dependent) and content (atrophy-independent) were investigated globally (bulk analysis) and regionally (voxel-based and atlas-based thalamic subnuclei analyses). The clinical impact of the observed MRI modifications was evaluated via regression models.ResultsWe identified reduced thalamic (P < .001) and increased pallidal (P < .001) mean iron concentrations in patients with MS versus controls. Global myelin and iron content in the basal ganglia did not differ between the two groups, while actual iron depletion was present in the thalamus (P < .001). Regionally, patients showed increased iron concentration in the basal ganglia (P ≤ .001) and reduced iron and myelin content in thalamic posterior-medial regions (P ≤ .004), particularly in the pulvinar (P ≤ .001). Disability was predicted by thalamic volume (B = -0.341, P = .02), iron concentration (B = -0.379, P = .005) and content (B = -0.406, P = .009), as well as pulvinar iron (B = -0.415, P = .003) and myelin (B = -0.415, P = .02) content, independent of atrophy.ConclusionsQuantitative MRI suggests an atrophy-related iron increase within the basal ganglia of patients with MS, along with an atrophy-independent reduction of thalamic iron and myelin correlating with disability. Absolute depletions of thalamic iron and myelin may represent sensitive markers of subcortical GM damage, which add to the clinical impact of thalamic atrophy in MS.

Dataset Information

Laboratory unraveling of matter accretion in young stars.

Publications

Laboratory unraveling of matter accretion in young stars.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets