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Session 80 - Central Stars of Planetary Nebulae.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center
During Cycle 5 of the HST\/ General Observer program we are carrying out a ``snapshot'' survey of the central stars of the nearer planetary nebulae (PNe). These snapshots are taken as short exposures in the V (F555W) and I (F814W) bands during brief scheduling opportunities.
The primary aim of the survey is to find close, resolved main-sequence companions of the central stars, which through main-sequence fitting will provide excellent distance estimates for the nebulae. This should in turn allow us to calibrate other, indirect distance methods, and thus materially improve the distance scale for PNe.
We will report a number of new discoveries of visual binaries in PNe, mostly with separations of less than 1'', including the central stars of NGC 650-1 (a resolved triple system), NGC 6309, NGC 7008, IC 4637, A 66, A 74, K 1-22, and Sp 3.
As a byproduct, the survey produces high-resolution images of the surrounding nebulae, and these have revealed a wealth of new information. Highlights of our early results include: a resolved circumstellar disk and jets around HD 44179, the central star of the ``Red Rectangle''; (2) an extensive network of subarcsecond filamentary dust in IC 4406; (3) ``point-symmetric'' or ``spiral'' structure in NGC 5307; (4) subarcsecond dust globules in the Ring Nebula, NGC 6720; and (5) details of the diametrically opposed jets emanating from the close-binary central star of K 1-2.
Supported by STScI Grant GO-6119.
