August 31, 2014

14.02.11: Sol Unleashes A Powerful Radio Flare.

An SDO spectrum composite of the sun as of Monday, February 14th.  (Credit: NASA/SDO).

Our nearest star unleashed the most powerful solar flare of 2011 thus far yesterday, and amateur and professionals alike were on hand to bear witness to the event. On Sunday, February 13th at approximately 1738 Universal Time, NASA’s Solar Dynamics Observatory detected the burst emanating from the large Earthward facing sunspot group 1158. Likewise, radio amateur astronomers detected a large simultaneous spike in the 19 to 21 MHz frequency range. [Read more...]

26.10.09:Seeing Starspots.

A simulation of Corot-2a with transiting hot Jupiter and starspots. (Simulation and phot by author).

A simulation of Corot-2a with transiting hot Jupiter and starspots. (Simulation and photo by author).

We know more about our Sun than any other star because it gives us the opportunity to study solar activity up close. But just how normal is it? Recently, astronomers have been able to spy activity on other suns, teasing the data out of exoplanet transits. These are planets that happen to cross the tiny visible face of their parent star as seen from our line of sight and thus exhibit a tiny but measurable dip in their apparent brightness. Earlier this year, a team at the Hamburg Observatory has been refining this technique by monitoring the star Corot-2a. A younger Sun-like star, Corot-2a spins once every 4.5 earth days and possesses a transiting “hot Jupiter” which orbits once every 1.74 days. Examining a statistical analysis of the light curve as seen by the European Space Agencies’ (ESA) prolific Corot space observatory has yielded “notches” in the smooth curve, a tell-tale sign of “starspot” activity. This was conducted over 80 successive transits. The goal is to begin puzzling together a “butterfly diagram” for alien suns, much like the familiar 11 year cycle diagram yielded by Sporer’s Law for our own Sun. Doubtless, other suns follow different cycles, and this data will add to our understanding of stellar evolution. This will also answer such questions about our own Sun, such as; why do sunspots never form above a particular latitude? Are there larger interwoven cycles? And just what was our Sun like in its juvenile days?

Death by Superflare?

An enormous sunspot group in 2001 that produced the largest flare seen in 25 years! (Credit: NASA/ESA/SOHO).

An enormous sunspot group in 2001 that produced the largest flare seen in 25 years! (Credit: NASA/ESA/SOHO).

A close runner-up in the pantheon of cosmic catastrophes is a killer flare courtesy of our Sun. While this may not be as lethal as a giant space rock, its also much more likely over the span of our short lifetimes. But what is the exact potential hazard posed by this threat? What has happened in the past? And what can be done about it? [Read more...]