Tag: XMM

Rotation and magnetic activity in M stars. The study: “HADES RV Programme with HARPS-N at TNG. X. The non-saturated regime of the stellar activity-rotation relationship for M dwarfs” of E. González-Álvarez (INAF-OAPA) recently appeared on A&A

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Stellar X-ray emission arises from their corona, which is the outer part of stellar atmosphere with low-density high-temperature (up to million degrees) plasma. Even if we lack a fully understanding of the details, we know that the intensity of stellar X-ray emission depends on the intensity and the morphology of stellar magnetic field.   The interior of stars of FGK

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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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Super-flares in the Pleiades. The study: “Simultaneous Kepler/K2 and XMM-Newton observations of superflares in the Pleiades” of M. G. Guarcello (INAF-OAPA) recently appeared on A&A

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Observations of the Sun show that our star hosts transient and violent phenomena which are due to the interaction between the plasma and the magnetic field produced in the interior of the Sun. Typical examples of this “magnetic activity” are the sunspots in the photosphere and the protuberances in the chromosphere. The solar flares are among those phenomena associated with

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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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IC 443: un caso unico di SNR con jet sovra-ionizzato

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di Mario Giuseppe Guarcello    ( segui mguarce)     Lo studio dei resti di supernova, nubi formate dalle esplosioni di supernova, sono oggetti di grande interesse scientifico. Queste nebulose, infatti, non sono semplicemente il residuo di uno dei fenomeni più violenti che  avvengono nell’Universo (un’esplosione di supernova dal collasso di una stella massiva, ossia le “core-collapse supernovae”, produce un’energia pari

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A peculiar supernova remnant. Published on A&A the study: “Discovery of a jet-like structure with overionized plasma in the SNR IC 443” of E. Greco (OAPA/UNIPA)

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Supernova remnants, i.e. the remnant of supernovae explosions, are among the most interesting astronomical objects. In fact, they are not only produced by one of the most violent phenomenon occurring in the Universe (the explosion of a supernova from the collapse of the core of a massive star, i.e. a “core-collapse supernova”, which emits the same energy of 1033 atomic

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Star formation history in Canis Major. Recently published by A&A “Star formation history of Canis Major OB1” of T. Santos-Silva

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Stars in several star forming regions are observed with a spread in age. This support the idea that star formation is a “slow” process which can propagate across a molecular cloud over million of years (as suggested, for instance, by the Palla & Stahler 2000 study), while several authors have instead suggested that star formation is a “fast” process (e.g.

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Supernovae and Jet, the letter: “Indications of a Si-rich bilateral jet of ejecta in the Vela SNR observed with XMM-Newton” by F. Garcia published on A&A

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The life cycle of very massive stars ends in supernovae explosions. During these violent phenomena, an amount of energy similar to that produced by the Sun during its entire lifetime,more than 10 billion years long, is released in few seconds. Besides, the atmosphere of the exploding star (the progenitor star) is ejected with a velocity in excess of 1000 km/sec.

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“X-ray orbital modulation of a white dwarf accreting from an L dwarf” pubblicato su A&A

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L’astronoma Beate Stelzer dell’Osservatorio Astronomico di Palermo è autrice dell’articolo “X-ray orbital modulation of a white dwarf accreting from an L dwarf” pubblicato su Astronomy & Astrophysics. Nell’articolo sono analizzati i dati ai raggi X ottenuti da osservazioni con il satellite XMM/Newton del sistema binario SDSS J121209.31+013627.7, composto da una nana bianca ed una nana bruna. Nello studio è riportata la

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