Update on Flare Stars WG activities

Transcript

1. Flare Stars Working Group Update Rachel Osten LOFAR TKP meeting

   Dec. 14, 2011 Meudon (virtually) Tuesday, December 13, 2011

2. Main Items • Science Goals • Recent Activity • Future

   Activity VLA full sun image at 330 MHz; image courtesy S. White Tuesday, December 13, 2011

3. Science Goals • study the plasma astrophysics occurring in cool,

   magnetically active stars - characterize nature of accelerated particle population in stellar flares - constrain rate of coronal mass ejections in high flaring rate stars - apply knowledge to radio transients classification • expect emissions to be coherent in nature, produced either from plasma radiation (ν∝sνp, with νp ∼9000√ne Hz) or cyclotron maser emission (ν∝sνB, with νB ∼2.8 B MHz) Tuesday, December 13, 2011

4. The Sun is the starting point for expectations about low

   frequency stellar radio emission example type III bursts example type II burst+(type IV also) Tuesday, December 13, 2011

5. Focus on 3 classes of magnetically active stars showing evidence

   for coherent emission at cm wavelengths Tuesday, December 13, 2011

6. ultracool dwarfs Focus on 3 classes of magnetically active stars

   showing evidence for coherent emission at cm wavelengths Tuesday, December 13, 2011

7. ultracool dwarfs active binaries Focus on 3 classes of magnetically

   active stars showing evidence for coherent emission at cm wavelengths Tuesday, December 13, 2011

8. ultracool dwarfs M dwarf flare stars active binaries Focus on

   3 classes of magnetically active stars showing evidence for coherent emission at cm wavelengths Tuesday, December 13, 2011

9. Science in Drifting Stellar Radio Bursts • radiating elements with

   intrinsic drift in the atmosphere, producing plasma radiation locally; dν/dt ∝ν • radiating elements with intrinsic drift, producing cyclotron maser emission locally; dν/dt ∝ν-4/3 • ISM effects dν/dt∝ν3 Tuesday, December 13, 2011

10. Observational Strategy • two phases: - targeted approach to learning

    about the diversity of behavior in 3 different classes of stars (active binaries, dMe flare stars, ultracool dwarfs) - use results and extend to serendipitous detections in Radio Sky Monitor Tuesday, December 13, 2011

11. Recent Activity • NSF proposal submitted to fund a post-doc

    in commissioning/science activities (3 yrs) • tied-array beam observations of a nearby M dwarf flare star (d=5 pc) AD Leo done over the summer, being looked at Tuesday, December 13, 2011

12. Future Activity • digest commissioning data • other observations? •

    simultaneous observations with LWA1? Tuesday, December 13, 2011