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The Hubble Helix
P.R. McCullough (STScI) and the Hubble Helix Team*
Abstract
(F502N). A few of the WFPC2 images, obFor the 14 hours of peak Leonid meteoroid tained in parallel, covered portions of the flux in November 2002, the Hubble Space Tele- nebula in [O I] (F631N), He II (F469N), or H scope was pointed away from the radiant, and (F656N). NICMOS/NIC3 observations were obtained at two locations on the nebula and the solar arrays were oriented to minimize two off, in H2 (F212N) and Paschen- (F187N). their cross-section. By coincidence, one of A few of the STIS parallel observations in [O the nearest and largest planetary nebulae, II] (F28X50OII) were located on the nebula. the Helix Nebula (NGC 7293), was nearly opThe main purpose of this presentation is to posite the incoming Leonids and could be advertise to all interested parties the availaobserved. A "Hubble Helix Team" of volunteers led by bility of the non-proprietary data via the HST archive. Initial data analysis by the Hubble M. Meixner (STScI) organized a nine-orbit campaign to observe the Helix with the ACS, Helix Team will be presented in this poster. WFPC2, NICMOS, and STIS. A contiguous 3 by 3 grid of 4kx4k-pixel ACS images covering much but not all of the Helix was exposed in two filters, H+[N II] (F658N) and [O III]
Fig. 4. Detail of a composite of ACS images in H+[N II] (F658N) in red-orange and [O III] (F502N) in cyan (blue-green).

ACS/WFC

WFPC2

NIC3 STIS CCD

10"
N 2' E Digitized Sky Survey

Fig. 1. HST fields of view superposed on DSS image of the Helix Nebula. because of an unexpected interaction between the "SAME POS AS" special requireFollowing the prediction of a large flux of Leonid meteoroids during the November ment and the use of a subarray for the central star of the planetary nebula. 2002 shower, the Hubble Space Telescope Project directed that HST be pointed direct- Results ly away from the radiant during the expectThe ACS images provide higher resolued peak, so as to minimize the exposed tion and greater angular coverage of the cross-section to the meteoroids. nebula than ever before. The WFPC2 imFortuitously, the anti-radiant point lies ages supplement the ACS images with adwithin 1° 3 of the Helix Nebula (NGC 7293), ditional wavelength and sky coverage. The . one of the nearest and angularly largest of NICMOS images detect the 2.12µm line of all planetary nebulae. Thus, our team at the H quite well at many positions (Figures 1 2 Space Telescope Science Institute (STScI) and 3). Very cursory visual inspection retook the opportunity to carry out an imag- veals no nebulosity in any of the NICMOS ing campaign on the Helix Nebula during Paschen- 1.87µm images and the STIS the nine-orbit Leonid stand-down. The re- [O II] 3727е images. sulting images have all been placed immeInterested scientists may access all of diately in the HST Archive, where they are the individual "Hubble Helix" images from available for analysis by any interested asthe HST Archive. The STScI Office of Public tronomers. This poster gives an overview of Outreach will release a color image in the the wide variety of information that is avail- near future, a representative detail of which able. is shown in Figure 4 . For safety's sake the MAMA detectors could not be used and the spacecraft's roll Acknowledgments We thank the many people at GSFC and angle was fixed in order to minimize the soSTScI who schedule and operate the lar panels' cross-section. telescope for making this opportunity Observations available to the astronomical community. We were able to operate all four HST In particular we thank Keith Kalinowski and cameras simultaneously: the newly instal- Dave Scheve who approved pointing the led Advanced Camera for Surveys (ACS), the HST at the Helix during the Leonids standWide Field Planetary Camera 2 ( WFPC2), down period. the Space Telescope Imaging Spectrograph (STIS), and the Near Infrared Camera and *The Hubble Helix Team refers to those Multiobject Spectrograph (NICMOS). The people who contributed to planning the nine pointings were optimized for contigu- observations and analyzing the data: ous coverage with ACS, leaving the other H.E. Bond, G. Chapman, Y.H. Chu, P. Cox, imagers pointing at adjacent sky regions W. Crothers, L.M. Frattare, R. Gilliland, (Figure 1). Table 1 summarizes the observa- M. Guerrero, R. Gruendl, F. Hamilton, tions, including an itemization of exposures R. Hook, P. Huggins, I. Jordan, C.D. Keyes, that were pointed "On" or "Off " the nebula. A. Koekemoer, K. Kwitter, Z.G. Levay, Since the Helix Nebula is too large to be P.R. McCullough, M. Meixner, M. Mutchler, K. Noll, C.R. O'Dell, N. Panagia, M. Reinhart, covered completely, even in nine ACS M. Robberto, K. Sahu, D. Soderblom, pointings, we chose to image the nebula's core and northwest side (Figure 2). The gap L. Stanghellini, C. Tyler, J. Valenti, A. Welty, and B. Williams. in the middle of the ACS mosaic occurred

Introduction

1'
E

N

10"
E

N

Fig. 2. Mosaic of ACS/WFC F658N (H+[N II]) exposures. Table 1 Spectral Lines Number of Exposures On / Off 46 46 20 18 2 12 4 8 / / / / / / / / 0 0 0 0 0 4 2 12 Exposure Time On / Off (hours) 5.12 4.92 2.56 2.35 0.24 2.20 0.43 1.00 / / / / / / / / ----------0.71 0.21 1.50

N E
Fig. 3. NIC3 F212N H2 2.12µm.

Config.

Filter

H 6562е + [N II] 6584е ACS/WFC F502N [O III] 5007е WFPC2 F656N H 6563е WFPC2 F631N [O I] 6300е WFPC2 F469N He II 4686е NIC3 F212N H2 2.12µm NIC3 F187N Pa 1.87µm STIS F28X50OII [O II] 3727е ACS/WFC F658N

AAS January 2003 · Seattle, WA · zgl 12/23/02