Fragmentation and mass segregation in the massive dense cores of Cygnus X

Details Fragmentation and mass segregation in the massive dense cores of Cygnus X Fragmentation and mass segregation in the massive dense cores of Cygnus X

2009-09-12

arxiv.org/abs/0909.2315v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

14 pages, 16 figures, submitted for publication in A&A

Scientific paper

We present Plateau de Bure interferometer observations obtained in continuum at 1.3 and 3.5 mm towards the six most massive and young (IR-quiet) dense cores in Cygnus X. Located at only 1.7 kpc, the Cygnus X region offers the opportunity of reaching small enough scales (of the order of 1700 AU at 1.3 mm) to separate individual collapsing objects. The cores are sub-fragmented with a total of 23 fragments inside 5 cores. Only the most compact core, CygX-N63, could actually be a single massive protostar with an envelope mass as large as 60 Msun. The fragments in the other cores have sizes and separations similar to low-mass pre-stellar and proto-stellar condensations in nearby protoclusters, and are probably of the same nature. A total of 9 out of these 23 protostellar objects are found to be probable precursors of OB stars with envelope masses ranging from 6 to 23 Msun. The level of fragmentation is globally higher than in the turbulence regulated, monolithic collapse scenario, but is not as high as expected in a pure gravo-turbulent scenario where the distribution of mass is dominated by low-mass protostars/stars. Here, the fractions of the total core masses in the high-mass fragments are reaching values as high as 28, 44, and 100 % in CygX-N12, CygX-N53, and CygX-N63, respectively, much higher than what an IMF-like mass distribution would predict. The increase of the fragmentation efficiency as a function of density in the cores is proposed to be due to the increasing importance of self-gravity leading to gravitational collapse at the scale of the dense cores. At the same time, the cores tend to fragment into a few massive protostars within their central regions. We are therefore probably witnessing here the primordial mass segregation of clusters in formation.

Affiliated with

Also associated with

No associations

Rating

Fragmentation and mass segregation in the massive dense cores of Cygnus X does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Fragmentation and mass segregation in the massive dense cores of Cygnus X, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fragmentation and mass segregation in the massive dense cores of Cygnus X will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-477331