2007/01/30 by Toshiya Ueta, Koji Murakawa, K. Murakawa +2 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Hubble space telescope #Laser #Linear polarization #Optics #Physics #Planetary nebula #Polarimetry #Polarization (electrochemistry) #Reflection nebula #Scattering #Starlight #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/511265
published as Astron.J.133:1345-1360,2007 · 27 pages, 14 figures, 3 tables; to appear in the Astronomical Journal March 2007 issue
arxiv created 2007/01/30 · openalex publication_date 2007/02/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The structure of the dusty circumstellar envelopes (CSEs) of proto-planetary nebulae (PPNs) reveals the mass-loss history of these sources and how such histories may differ for elliptical (SOLE) and bipolar (DUPLEX) PPNs. To study the PPN structures via dust-scattered linearly polarized starlight, we have compiled the imaging-polarimetric data for all 18 evolved stars that have been obtained to date with NICMOS on board the Hubble Space Telescope . This alternative imaging technique provides a unique way to probe the distribution of dust grains that scatter light around evolved stars. The new perspective gained from the imaging-polarimetric data has revealed several new aspects to the structures of PPNs. Point symmetry is a prevalent imaging-polarimetric characteristic resulting from the azimuthal density gradient in the CSEs. Among these point-symmetric nebulae, three detailed morphological types can be differentiated by their polarized intensity, I p , and polarization strength, P . While the azimuthal density gradient is reversed above and below the equatorial plane in optically thicker bipolar nebulae, there is no gradient reversal in optically thinner elliptical nebulae. The equatorial plane of the system defined by the integrated angle of polarization is not necessarily orthogonal to the axis of the apparent bipolar structure in the total intensity data.