(cba:news) V4641 Sgr

Joe Patterson jop at astro.columbia.edu
Fri Jul 1 07:16:44 EDT 2005

Oops, I forgot V4641 Sgr!

Many of you know that this star went into a flaring state a couple weeks
ago, then subsided, then came back... and who knows what it has up its
sleeve for the future?  Berto has been following it prodigiously, with
good coverage also from Tom Richards and Peter Nelson.

There's no mystery why the star is so popular - it's plenty bright and
specializes in these huge (1 mag) flares, along with many more smaller
ones.  The reason I forget such a spectacular target is that I'm not quite
sure how to use the data.  Most of our projects involve discovery or
tracking of a *period*.  Periods are deep properties of a star, often
revealing of the basic underlying dynamics (masses), or at least the
classification and eruption patterns of the star.  So we can make a lotta
hay outa them!  Flares are another story altogether.  They jump up and
tantalize you... and then you get your ruler out and try to measure the
damn thing, amplitude, time, duration, whatever... and then another
occurs, and then 20 more.  And hardly ever can you find any pattern.
The day will probably come when we understand such things, but it has not
yet arrived.

That's why I overlooked V4641 Sgr.  But if everyone agreed with me, then
we'd *certainly* never understand these flares - and they're admittedly
very tantalizing.  I'm just trying to make recommendations for projects
which I think have a clear astrophysical goal, and (usually) that I'm
personally interested in steering through to publication.  That's a
limited viewpoint... and once you have that camera in your hands, you're
the boss of your local sky.  With sometimes spectacular results, as the
recent publicized successes of Berto, Jennie, and Tonny illustrate!


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