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Helioseismic Measurement of Solar Torsional Oscillations
Thompson, M. J.; Christensen-Dalsgaard, J.; Schou, J. +2 more
Bands of slower and faster rotation, the so-called torsional oscillations, are observed at the Sun's surface to migrate in latitude over the 11-year solar cycle. Here, we report on the temporal variations of the Sun's internal rotation from solar p-mode frequencies obtained over nearly 6 years by the Michelson Doppler Imager (MDI) instrument on bo…
A Classical Nova, V2487 Oph 1998, Seen in X-rays Before and After Its Explosion
Hernanz, Margarita; Sala, Glòria
Classical nova explosions are very energetic and frequent phenomena caused by explosive hydrogen burning on top of an accreting white dwarf. Observations of the recent nova V2487 Oph 1998 by the X-ray Multi-Mirror satellite (XMM-Newton) provide evidence that accretion (probably on a magnetic white dwarf) was reestablished as early as 2.7 years aft…
Formation of the Three-Ring Structure Around Supernova 1987A
Tanaka, T.; Washimi, H.
From a magnetohydrodynamic simulation, we reproduce a three-ring structure in the circumstellar space of the supernova (SN) 1987A observed by the Hubble Space Telescope. When a star develops from a red supergiant (RSG) to a blue supergiant (BSG) just before the SN explosion, a wind-wind interaction occurs between the slow stellar wind from the RSG…