A variable jet model for the H alpha emission of HH 444

作者：Raga A C^*; Riera A; Gonzalez Gomez D I

来源：Astronomy & Astrophysics, 2010, 517: A20.

DOI：10.1051/0004-6361/200913908

• circumstellar matter
• ISM: jets and outflows
• Herbig-Haro objects
• ISM: individual objects: HH 444
• stars: formation

Context. HH 444 is one of the first Herbig-Haro (HH) jets discovered within a photoionized region.
Aims. We re-analyze the H alpha and red [S II] HST images of HH 444, and calculate the width of the jet as a function of distance from the source. We compare the H alpha image with predictions from variable ejection velocity jet models.
Methods. The determination of the jet's width is done with a non-parametric, wavelet analysis technique. The axisymmetric, photoionized jet simulations are used to predict H alpha maps that can be directly compared with the observations.
Results. Starting with a thin jet (unresolved at the resolution of the observations), we are able to produce knots with widths and morphologies that generally agree with the H alpha knots of HH 444. This agreement is only obtained if the jet axis is at a relatively large, similar to 45 degrees angle with respect to the sky. This agrees with previous spectroscopic observations of the HH 444 bow shock, which imply a relatively large jet axis/plane of the sky angle.
Conclusions. We conclude that the general morphology of the chain of knots close to V510 Ori (the HH 444 source) can be explained with a variable ejection velocity jet model. For explaining the present positions of the HH 444 knots, however, it is necessary to invoke a more complex ejection velocity history than a single-mode, periodic variability.

• 出版日期2010-7