Program: GN-2014B-Q-1

Title:Probing the molecular hydrogen of small-scale structures in planetary nebulae
PI:Stavros Akras
Co-I(s): Gerrardo Ramos-Larios, Denise Rocha Goncalves

Abstract

We propose to obtain deep, high-resolution, near-infrared (H$_2$ and Br$\gamma$) images of the small-scale low-ionization structures (LISs, knots and jets) of Galactic Planetary Nebulae (PNe). LISs' densities where surveyed in the optical (so accouting for the ionized matter) and shown to be a factor between 10 and 100 LESS DENSE than either the other nebular components or the theoretical predictions. Therefore we expect that the missing matter of the LISs is made of atomic and molecular gas, which cannot be accessed in the optical. The main goals of this project are: (1) to detect the faint near-IR H$_2$ emission from LISs, and (2) to derive the H$_2$ 1-0 S(1) to 2-1S (1) line ratio to study the excitation mechanism of LISs and also of the other nebular components (rims, shells and haloes). Moreover, even if these deep observations result in the non-detection of molecular hydrogen emission, attributed to the LISs, these observations will definitely exclude the theoretical formation models that predict LISs denser than the ionized rims or sheels of the nebula. The proposed project constitute a major step forward --never tried before with a 8-m class facility-- on our understanding of the nature of knots and jets in PNe, a key open problem in the field.

Publications using this program's data