Proper Motions of Young Stellar Outflows in the Mid-infrared with Spitzer (irac). I. the Ngc 1333 Region

We use two 4.5μm Spitzer (IRAC) maps of the NGC 1333 region taken over a ∼ 7 yr interval to determine proper motions of its associated outflows. This is a first, successful attempt at obtaining proper motions of stellars outflow from Spitzer observations. For the outflow formed by the HerbigHaro objects HH7, 8 and 10, we find proper motions of ∼ 9-13 km s−1, which are consistent with previously determined optical proper motions of these objects. We We determine proper motions for a total of 8 outflows, ranging from ∼ 10 to 100 km s−1. The derived proper motions show that out of these 8 outflows, 3 have tangential velocities ≤ 20 km s−1. This result shows that a large fraction of the observed outflows have low intrinsic velocities, and that the low proper motions are not merely a projection effect. Subject headings: ISM: jets and outflows — ISM: Herbig-Haro objects — ISM: star formation — circumstellar matter — stars: formation — infrared: ISM — ISM: individual objects (HH7-11) — ISM: individual objects (NGC 1333)