MAGNETIC STORM ON COMET LOVEJOY? Around the world, observers of bright Comet Lovejoy (C/2014 Q2) are reporting activity in the comet’s sinuous blue ion tail. Last night, Italian photographer Rolando Ligustri used a remotely-controlled telecope in Spain to capture this ‘plasma blob’ billowing down the tail, away from the comet’s core:
This could be a sign that a magnetic storm in underway. Observers of comets frequently witness plasma blobs and ‘disconnection events’ in response to CMEs and gusts of solar wind. In extreme cases, a comet’s tail can be completely torn off.
The underlying physics is akin to terrestrial geomagnetic storms. When magnetic fields around a comet bump into oppositely-directed magnetic fields in a CME, those fields can link together or “reconnect.” The resulting burst of magnetic energy can make waves, blobs, or even ruptures in the comet’s tail. When CMEs hit Earth, a similar process takes place in the planet’s magnetosphere powering, among other things, the aurora borealis.
For readers who wish to monitor the effects of space weather on Lovejoy, the comet is easy to find. It is shining like a 4th magnitude star (barely visible to the unaided eye and an easy target for backyard telescopes) not far from the constellation Orion in the midnight sky. For accurate pointing of telescopes, please use this ephemeris from the Minor Planet Center.