Astrophys. J., 745, 117 (2012/February-1)
Initial conditions for star formation in clusters: physical and kinematical structure of the starless core Oph A-N6.
BOURKE T.L., MYERS P.C., CASELLI P., DI FRANCESCO J., BELLOCHE A., PLUME R. and WILNER D.J.
Abstract (from CDS):
We present high spatial (<300 AU) and spectral (0.07 km/s) resolution Submillimeter Array observations of the dense starless cluster core Oph A-N6 in the 1 mm dust continuum and the 3-2 line of N2H+ and N2D+. The dust continuum observations reveal a compact source not seen in single-dish observations, of size ∼1000 AU and mass 0.005-0.01 M☉. The combined line and single-dish observations reveal a core of size 3000x1400 AU elongated in a NW-SE direction, with almost no variation in either line width nor line center velocity across the map, and very small non-thermal motions. The deuterium fraction has a peak value of ∼0.15 and is >0.05 over much of the core. The N2H+ column density profile across the major axis of Oph A-N6 is well represented by an isothermal cylinder, with temperature 20 K, peak density 7.1x106/cm3, and N2H+ abundance 2.7x10–10. The mass of Oph A-N6 is estimated to be 0.29 M☉, compared to a value of 0.18 M ☉ from the isothermal cylinder analysis, and 0.63 M☉for the critical mass for fragmentation of an isothermal cylinder. Compared to isolated low-mass cores, Oph A-N6 shows similar narrow line widths and small velocity variation, with a deuterium fraction similar to "evolved" dense cores. It is significantly smaller than isolated cores, with larger peak column and volume density. The available evidence suggests that Oph A-N6 has formed through the fragmentation of the Oph A filament and is the precursor to a low-mass star. The dust continuum emission suggests that it may already have begun to form a star.
ISM: individual: Oph A-N6 - stars: formation - stars: low-mass
View the reference in ADS
To bookmark this query, right click on this link: simbad:2012ApJ...745..117B and select 'bookmark this link' or equivalent in the popup menu