Tag: X-ray

Discovered an X-ray cycle in a 400 million years old star. The study: “An X-ray activity cycle on the young solar-like star ɛ Eridani” of M. Coffaro (Eberhard-Karls Universität Tübingen) appeared on A&A

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The intensity of Solar magnetic activity and of the related phenomena (such as sunspots and flares) varies with an 11-years cycle. In order to understand whether such an activity cycle is common among solar-type stars, since 1966 a project based on the Observatory of Mt. Wilson is collecting measurements of the cromospheric activity of a large sample of low-mass stars

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Flares and X-ray fluoresence in protostars. The study: “Deep X-ray view of the Class I YSO Elias 29 with XMM-Newton and NuSTAR” of I. Pillitteri (INAF-OAPA) recently appeared on A&A

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“Protostars” are stars a few million years old, which are still accreting gas and contracting for their own gravity, and whose nucleus has not reached yet the temperature and pressure necessary for the onset of thermonuclear reactions. The youngest protostars are still surrounded by a protoplanetary disk of gas and dust (class II protostars) or even by an accreting envelope

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Recently published on ApJ the study “Investigating the Structure of Vela X” of P. Slane (CfA) on the morphology of the Vela supernova remnant

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What remains after a supernova explosion, which is among the most energetic phenomena in the Universe, is an expanding cloud interacting with the surrounding interstellar medium (the “supernova remnants”) and a compact object produced by the contraction of the nucleus of the progenitor star. Given its proximity to the Sun (“only” 945 light years), the Vela supernova remnant is one

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Testing X-IFU performances. Published on SPIE: “Testing the X-IFU calibration requirements: an example for quantum efficiency and energy resolution” of E. Cucchetti (IRAP, CNRS, Universite’ de Toulouse)

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of Mario Giuseppe Guarcello    ( follow mguarce)   In the past ten years the X-ray Universe has been explored mainly by two telescopes: the NASA satellite Chandra and the ESA satellite XMM-Newton. These two telescopes are still operating efficiently. However, the scientific community has already started planning the next generation of instruments for X-ray astronomy. In Europe, the future in

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Diffuse X-ray emission in massive star formin region. Published on ApJS “Diffuse X-ray emission in the Cygnus OB2 association” of J. F. Albacete-Colombo (Universidad de Rıo Negro)

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During their short existence lasting only few million years, massive stars (more massive than 8 solar masses with spectral type O and B-early) strongly affect the surrounding environment thanks to their intense UV radiation and stellar winds. A single O star, in fact, can loose about 10-6 solar masses of gas in a wind reaching velocities of 1600–2500 km s−1 (Stevens & Hartwell, 2003).

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INAF-OAPA researchers observe for the first time X-ray emission from an active region in a B star

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The study of the X-ray emission from stars provides an unmatched view of those energetic phenomena occurring in stars. In massive stars (O and early B stars), soft X-ray photons (less energetic than about 1 keV) are emitted from shocks in stellar winds. More energetic photons (the hard X-ray emission) is due to colliding stellar winds in binary systems or

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Osservata per la prima volta emissione ai raggi X associata ad una regione attiva in una stella B. Pubblicato su A&A lo studio: “Detection of magnetic field in the B2 star ρ Ophiuchi A with ESO FORS2” di I. Pillitteri (INAF-OAPA)

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di Mario Giuseppe Guarcello    ( segui mguarce)     Lo studio dell’emissione di raggi X dalle stelle offre molte diagnostiche di fenomeni stellari ad alta energia. Nelle stelle massive (di classe spettrale O le B più calde) raggi X “soffici” (con energia generalmente minore di 1keV, corrispondente a temperature minori di 10 milioni di gradi) sono emessi in shock nei

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Palermo ospiterà il meeting “Exploring the Hot and Energetic Universe”

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di Mario Giuseppe Guarcello    ( segui mguarce)     Dal 24 al 27 Settembre 2018, si terrà a Palermo, presso il Real Teatro di S. Cecilia, il meeting internazionale “Exploring the Hot and Energetic Universe”, dedicato al telescopio ai raggi X Athena (Advanced Telescope for High-Energy Astrophysics). Athena, una missione in fase di studio del programma “Cosmic Vision” di ESA

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Pubblicato lo studio: “X-ray survey of the North-America and Pelican star-forming complex (NGC 7000/IC 5070)” di F. Damiani (INAF-OAPA)

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di Mario Giuseppe Guarcello    ( segui mguarce)     Poche ma estremamente importanti…. Le stelle con masse maggiori di 6 masse solari ed una temperatura efficace maggiore di 15000 gradi (stelle O e stelle B1-B5) sono particolarmente rare nell’Universo e la loro evoluzione si compie in pochi milioni di anni, un tempo piuttosto breve se paragonato ai miliardi di anni

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