Chemical and dynamical properties of a Very Low Luminosity Object - DCE065

• Main Authors: Hung, Chao-Ling, 洪肇伶
• Other Authors: Lai, Shih-Ping
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/54443425534944260132

碩士 === 國立清華大學 === 天文研究所 === 98 === We study the chemical and dynamical properties of a very low luminosity object - DCE065 using the Submillimeter Array and complementary single dish observations. The continuum and N2D+ emission show that DCE065’s parent core with a mass of 0.24 M⊙ is in flattened structure. A small velocity gradient along the major axis of the N2D+ disk is marginally detected, suggesting that the rotational energy alone is insufficient to support the parent core. The very young and cold chemical features are evidenced by the high N2D+/N2H+ abundance ratio of 0.1, non-detection of CO evaporation in the central region and a constant N2D+ abundance profile. These features suggest that DCE065 may not have experienced a strong accretion phase or it has already left the burst accretion phase for a long time. The 12CO emission shows a large red shifted triangle feature in the PV diagrams which can be explained with an outward motion. Since the mass, momentum and energy of the expanding material are similar to those of the less energetic outflows in Perseus, the origin of the outward motion signature shown in the 12CO emission is probably due to outflow activities. Because the parent core mass is very low, DCE065 may destined to form a brown dwarf if its current accretion rate is higher than 3 × 10−8 M⊙ yr−1. The young chemical features and possible outflow activities shown in DCE065 support the scenario that a brown dwarf forms from collapsing processes similar to typical low mass stars.