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Title: The disappearing envelope around the transitional class I object L43

We present Submillimeter Array interferometric observations of the {sup 12}CO (J = 2-1), {sup 13}CO (J = 2-1), and C{sup 18}O (J = 2-1) lines and 225 GHz continuum emission and Submillimeter Telescope single-dish observations of C{sup 18}O (J = 2-1) toward L43, a protostellar object in transition from Class I to II. The 225 GHz continuum emission shows a weak (∼23.6 mJy), compact (<1000 AU) component associated with the central protostar. Our simulated observations show that it can be explained by dust thermal emission arising from an envelope which has a hole or a constant intensity region within a few hundred AU of the protostar. This suggests the disappearance or a lower concentration distribution of the envelope on a small scale. The {sup 12}CO and {sup 13}CO emission exhibit molecular outflows to the south and north. The C{sup 18}O emission shows two molecular blobs, which correspond to the reflection nebulosity seen in near-infrared images, while there is no C{sup 18}O emission associated with the protostar. The near-infrared features are likely due to the scattering at the positions of the blobs. The visible scattering features should result from the optical thinness of the envelope material, which is consistent with themore » less-concentrated distribution in the continuum emission. From single-dish observations, we found that the mass of the envelope (∼1.5 M{sub ☉}) + protostar (∼0.5 M{sub ☉}) is comparable with the virial mass of M{sub vir} = 1.0 M{sub ☉} within 40''. This suggests that the envelope is likely gravitationally bound. We suggest that the protostellar envelope of L43 has been disappearing by consumption through accretion, at least in the close vicinity of the protostar.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)
  2. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)
  3. National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka-shi, Tokyo 181-8588 (Japan)
  4. Graduate University for Advanced Studies, Shonan International Village, Hayama-cho, Miura-gun, Kanagawa 240-0193 (Japan)
  5. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
22365735
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 789; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CARBON 12; CARBON 13; CARBON MONOXIDE; DISTRIBUTION; EMISSION; MASS; OXYGEN 18; PROTOSTARS; REFLECTION; SCATTERING; SIMULATION; STARS; TELESCOPES