Solar Flares and Coronal Mass Ejections : A Statistically Determined Flare Flux-CME Mass Correlation

s of recently accepted papers Solar Flares and Coronal Mass Ejections: A Statistically Determined Flare Flux CME Mass Correlation Alicia Aarnio, Keivan Stassun, W. Jeffrey Hughes and Sarah McGregor 1 University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109, USA 2 Department of Physics and Astronomy, Vanderbilt University, USA 3 Department of Astronomy and Center for Integrated Space Weather Modeling, Boston University, USA E-mail contact: aarnio at umich.edu In an effort to examine the relationship between flare flux and corresponding CME mass, we temporally and spatially correlate all X-ray flares and CMEs in the LASCO and GOES archives from 1996 to 2006. We cross-reference 6,733 CMEs having well-measured masses against 12,050 X-ray flares having position information as determined from their optical counterparts. For a given flare, we search in time for CMEs which occur 10-80 minutes afterward, and we further require the flare and CME to occur within ±45 in position angle on the solar disk. There are 826 CME/flare pairs which fit these criteria. Comparing the flare fluxes with CME masses of these paired events, we find CME mass increases with flare flux, following an approximately log-linear, broken relationship: in the limit of lower flare fluxes, log(CME mass) ∝ 0.68×log(flare flux), and in the limit of higher flare fluxes, log(CME mass) ∝ 0.33×log(flare flux). We show that this broken power-law, and in particular the flatter slope at higher flare fluxes, may be due to an observational bias against CMEs associated with the most energetic flares: halo CMEs. Correcting for this bias yields a single power-law relationship of the form log(CME mass) ∝ 0.70× log(flare flux). This function describes the relationship between CME mass and flare flux over at least 3 dex in flare flux, from ≈10−10 W m. Accepted by Solar Physics http://www.astro. lsa.umich.edu/~aarnio/preprints/AarnioSola2010.pdf On the propensity of the formation of massive clumps via fragmentation of driven shells S. Anathpindika 1 Indian Institute of Astrophysics, Bangalore-560034, India E-mail contact: sumedh a at iiap.res.in Early type massive stars drive thin, dense shells whose edges often show evidence of star-formation. The possibility of fragmentation of these shells, leading to the formation of putative star-forming clumps is examined with the aid of semi-analytic arguments. We also derive a mass-spectrum for clumps condensing out of these shells by performing Monte-Carlo simulations of the problem. By extending on results from our previous work on the stability of thin, dense shells, we argue that clump-mass estimated by other authors in the past, under a set of simplifying assumptions, are several orders of magnitude smaller than those calculated here. Using the expression for the fastest growing unstable mode in a shock-confined shell, we show that fragmentation of a typical shell can produce clumps with a typical mass > ∼10 3 M⊙. It is likely that such clumps could spawn a second generation of massive and/or intermediate-mass stars which could in turn, trigger the next cycle of star-formation. We suggest that the ratio of shell thickness-to-radius evolves only weakly with time. Calculations have been performed for stars of seven spectral types, ranging from B1 to O5. We separately consider the stability of supernova remnants.