Archive
Subaru Telescope Observers Superflare Stars With Large Starspots
Artificial image of a superflare star. Credit: Kyoto University
A team of astronomers has used the High Dispersion Spectrograph on the Subaru Telescope to conduct spectroscopic observations of Sun-like “superflare” stars first observed and cataloged by the Kepler Space Telescope. The investigations focused on the detailed properties of these stars and confirmed that Sun-like stars with large starspots can experience superflares.
The team, made up of astronomers from Kyoto University, University of Hyogo, the National Astronomical Observatory of Japan (NAOJ), and Nagoya University, targeted a set of solar-type stars emitting very large flares that release total energies 10-10000 times greater than the biggest solar flares. Solar flares are energetic explosions in the solar atmosphere and are thought to occur by intense releases of magnetic energy around the sunspots. Large flares often cause massive bursts of high-speed plasma called coronal mass ejections (CMEs), can lead to geomagnetic storms on Earth. Such storms can have severe impacts on our daily life by affecting such systems as communications and power grids.
Scientists Shed Light On Riddle Of Sun’s Explosive Events
Four decades of active research and debate by the solar physics community have failed to bring consensus on what drives the sun’s powerful coronal mass ejections (CMEs) that can have profound “space weather” effects on Earth-based power grids and satellites in near-Earth geospace.
In a paper just published in Nature Physics, an international team of space scientists, including a researcher from the University of New Hampshire’s Space Science Center (SSC), explains the mysterious physical mechanisms underlying the origin of CMEs. Their findings, based on state-of-the-art computer simulations, show the intricate connection between motions in the sun’s interior and these eruptions and could lead to better forecasting of hazardous space weather conditions.
“By studying CMEs we learn not only about the drivers of space weather but also about the structure of the atmosphere of the sun and other sun-like stars,” says lead author Ilia Roussev of the Yunnan Astronomical Observatory, Chinese Academy of Sciences (CAS) and the Institute for Astronomy at the University of Hawaii at Manoa.
Full Story: http://www.eos.unh.edu/news/indiv_news.shtml?NEWS_ID=1334
Prediction System To Protect Astronauts From Solar Storms
With the impending solar maximum expected to bring heightened rates of flares and coronal mass ejections (CMEs), putting at risk an ever-increasing human presence in space, Oh et al. designed and assessed a prediction system to keep astronauts safe from these solar storms. During a solar flare or CME, particles from the Sun can be accelerated to very high energies-in some cases travelling near the speed of light. Protons with energies surpassing 100 megaelectron volts essentially sandblast everything in their path. Though people on Earth are protected by the planet’s magnetic field and thick atmosphere, astronauts in spacecraft beyond low-Earth orbit, or people at high altitudes near the poles, can be exposed to this increased radiation. This can potentially cause radiation sickness, with symptoms such as fever and vomiting.
Full Story: http://www.agu.org/news/press/jhighlight_archives/2012/2012-06-29.shtml#two
Almost X-Flare & Incoming CME
This morning, Jan. 23rd around 0359 UT, big sunspot 1402 erupted, producing a long-duration M9-class solar flare. The explosion’s M9-ranking puts it on the threshold of being an X-flare, the most powerful kind. NASA’s Solar Dynamics Observatory captured the flare’s extreme ultraviolet flash.
The Solar and Heliospheric Observatory (SOHO) and NASA’s twin STEREO spacecraft detected a CME rapidly emerging from the blast site: movie. Analysts at the Goddard Space Weather Lab say the leading edge of the CME will reach Earth on Jan. 24 at 14:18UT (+/- 7 hours). Their animated forecast track shows that Mars is in the line of fire, too; the CME will hit the Red Planet during the late hours of Jan. 25.
Full Story: http://spaceweather.com/archive.php?view=1&day=23&month=01&year=2012
Solar Storms Could ‘Sandblast’ the Moon
Credit: NASA/SDO
Solar storms and associated Coronal Mass Ejections (CMEs) can significantly erode the lunar surface according to a new set of computer simulations by NASA scientists. In addition to removing a surprisingly large amount of material from the lunar surface, this could be a major method of atmospheric loss for planets like Mars that are unprotected by a global magnetic field.
The research is being led by Rosemary Killen at NASA’s Goddard Space Flight Center, Greenbelt, Md., as part of the Dynamic Response of the Environment At the Moon (DREAM) team within the NASA Lunar Science Institute.
CMEs are basically an intense gust of the normal solar wind, a diffuse stream of electrically conductive gas called plasma that’s blown outward from the surface of the Sun into space. A strong CME may contain around a billion tons of plasma moving at up to a million miles per hour in a cloud many times the size of Earth.
Full Story: http://www.nasa.gov/topics/solarsystem/features/dream-cme.html
