Saturday, February 19, 2011

Mighty flares, few aurorae (yet) - and lots of media confusion

It had to happen, after this long solar minimum: The moment activity picks up - with several M flares and even one with X-class in mid-February - the media go overboard with excitement, science institutions jump on the wagon to tout their related work, and it's up to sober bloggers to put it all into perspective ... Events in reverse oder: • There was an M flare on Feb. 18, and the sunspot groups 1161 and 1162 are causing waves of ionization in our ionosphere and should be watched carefully.

The X-class flare on Feb. 15 (more and more) from AR 1158 was first thought to be capable of causing great effects (like in this report ...), but it didn't happen and predictions remain difficult, as e.g. this analysis points out (earlier) - more coverage here, here, here, here (earlier), here, here, here (earlier), here, here, here, hier and hier. • The M flare on Feb. 13 was covered e.g. here, here and here - and at the time was not the biggest of cycle. • Regarding solar activity also stories on the worldwide CALLISTO network and the role of IBEX as a monitor.

In other news a movie of a lunar flash (more details) recorded on Feb. 11, a pessimistic Elenin analysis (recent observations point to only +6 mag. at max.) and fireballs in Philadelphia (more) and Chicago (more). • Amateur analysis of Haumea and its lightcurve. • And a speculative paper on "a jovian mass solar companion in the Oort cloud" makes headlines (more, more, many more, mehr and mehr), so that eventually NASA had to comment on the (non-)issue ...

Sunday, February 13, 2011

Closest non-impacting object in our asteroid catalog came by, changed direction by 60°

Asteroid 2011 CQ1 made a record close Earth approach on February 4th, 14 hours after its discovery. It passed to within 0.85 Earth radii (5480 km) of the Earth's surface: This 'flying sofa', only about one meter in diameter, is the closest non-impacting object in our asteroid catalog to date. Prior to the Earth close approach, this object was in a so-called Apollo-class orbit that was mostly outside the Earth's orbit. Following the close approach, the Earth's gravitational attraction modified the object's orbit to an Aten-class orbit where the asteroid spends almost all of its time inside the Earth's orbit. The close Earth approach changed the asteroid's flight path by about 60°. There are nearly a billion objects of this size and larger in near-Earth space and one would expect one to strike Earth's atmosphere every few weeks on average where they airburst; only rarely do even a few small fragments reach the ground.

In other small bodies news a paper describes the outcome of NEOWISE, the (full) mission of the WISE observatory. • Asteroid transits over planet disks are more frequent than one might think. • Rob McNaught's 58th comet has been discovered, also pics of a small comet near a galaxy and of Hartley 2 near M 50 (more). • A paper on human perception may be of relevance for visual meteor observers. • A nice fireball over Italy, also discussed here. • Debate over the first impact crater in China and the meaning of the Kamil structure for impact physics. • Regarding larger bodies, the storm on Saturn on Feb. 6 and Feb. 5 (plus a progress report, rather old Keck pics of the SEB revival on Jupiter and Jupiter & the Moon on Feb. 6.

In solar research we celebrate one year of the SDO in orbit. • Results on CME ripple structures and particle acceleration near Earth. • The two STEREO s/c are now seeing the entire Sun, als also hailed here, here, here, here, here, here, here, here, here, here, here and hier. • How LOFAR saw the solar eclipse on Jan. 4 in radio. • A new sequence for SN 2011B. • A bright outburst of star (with a crazy name) and an outburst of Z Cam. • New insights into Eps Aur. • Amateur imaging of a z=6 object. • Some images of NanoSail D (also here and here), plus the flare geometry. • And finally, returning to SDO's launch a year ago, a new kind of halo effect triggered by its rocket.