APOD/J.Schmidt This work Witnessing the Shaping of the Archetypical "Butterfly" Planetary Nebula NGC 6302 with HST's Wide Field Camera 3 Joel Kastner Chester F. Carlson Center for Imaging Science , School of Physics & Astronomy & Laboratory for Multiwavelength Astrophysics Rochester Institute of Technology, Rochester, NY Chair, AAS Committee on Employment
Collaborators: Paula Moraga (RIT), Jesse Bublitz (NRAO Green Bank Obs.), B. Balick (U Wash.), R. Montez Jr (CfA | Harvard&SAO), A. Frank (U Rochester), & E. Blackman (U Rochester) Planetary nebulae: touchstones for understanding interacting winds and interacting binary systems • Planetary nebula: recently ejected outer layers of a red giant star that are being ionized by UV radiation from the former core of the progenitor star • The UV-bright core is a future white dwarf
• Transition from (spherical) red giant to (highly aspherical!) planetary nebula takes place over a few thousand years…an (astronomical) eyeblink! • What physical processes & mechanisms Color composites of our explain this rapid structural change? HST/WFC3 images of NGC 6302 (top) & NGC 7027 (right) • Theory: the many, varied shapes of planetary nebulae are the direct result of interacting [credit: J. Schmidt, APOD, STScI] (colliding) stellar winds • “New” wind from the core impinging on the “old” wind from red giant • PN shapes also likely betray the presence and influence of a binary companion to the PN progenitor star HST/WFC3 Survey of NGC 7027 & NGC 6302: Motivation • As HST approached the end of its 3rd decade of service, the tremendous potential of HST’s Wide Field Camera 3 to obtain a comprehensive set of emission-line images – from near-UV through optical to near-IR -- had yet to be exploited for any planetary nebula • So, we undertook the first such comprehensive HST/WFC3 emission- line studies, targeting well-studied NGC 7027 and NGC 6302 – two of the youngest and (evidently) most rapidly evolving planetary nebulae • Both nebulae feature axisymmetric and point-symmetric (“bipolar”) structures and – despite strong UV radiation their very hot central stars -- both harbor large masses of molecular gas and dust HST/WFC3 Surveys of NGC 7027 & NGC 6302: The Program* Science Goal(s) WFC3 Filters Lines/Species/Bands Targeted reach of central star FQ243N, F343N (near-UV) [Ne IV], [Ne V] photoionization; heat conduction spatial distributions of F487N, F502N, F656N, F673N H-beta, [O III], H-alpha, shocks vs. (optical) [S II] photoionization F128N, F130N, F164N, F167N Pa-beta, [Fe II] (+ adjacent (near-IR) continuum) scattered light dust F110W, F160W (near-IR) ‘J’ & ‘H’ band continuum imaging *Data obtained Sept/Oct 2019. F502N & F673N imaging of NGC 6302 failed; repeated March 2020, with addition of F658N to image [N II] The iconic, complex planetary nebulae NGC 6302 & NGC 7027* NGC 6302: fast facts • Distance: roughly 3600 light years • In the general direction of the Galactic Center (but much closer to us!) • central star temperature: roughly 300,000 Kelvin • One of the hottest stars known…apart from NGC 7027’s central star! • Nebula ejected by its central star over the past ~2000 years • In addition to the brightly glowing ionized gas seen at optical wavelengths, the nebula includes large masses of dust & molecular gas • “Poster child” for WFC3 1st light in 2009 • Imaged in 5 narrow-band visible-wavelength filters • Apparent detection of central star (Szyszka+2009) NGC 6302: HST/WFC3, 2009
*NGC 7027: stay tuned for presentations by Paula Moraga (507.002) and Jesse Bublitz (507.003)! NGC 6302: HST/WFC3 image suite 140” FOV (~0.9 pc)
WFC3 UVIS module images
WFC3 IR module images HST/WFC3 imaging of NGC 6302: New Results Disentangling shocks, excitation, & extinction F128N/F487N, Pa-beta/H-beta F658N/F656N, [N II]/H-alpha F164N-F167N, [Fe II] Multi-epoch HST/WFC3 imaging of NGC 6302: New Results What (& where) is its “central star”?
F160W (H band) F130N (narrow J) F110W (YJ band) F673N [S II] difference image, 2019-2009
(obscured) central star is actually here? “central star ” was here in 2009…but here in 2019: foreground field star! HST/WFC3 imaging of NGC 6302: Witnessing the shaping of a planetary nebula