Other
Scientific paper
May 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009aas...21431502e&link_type=abstract
American Astronomical Society, AAS Meeting #214, #315.02; Bulletin of the American Astronomical Society, Vol. 41, p.760
Other
Scientific paper
Deuterated ions, especially H2D+ and N2D+, are abundant in cold (˜10; K), dense (˜105 cm-3) regions, in which CO is frozen out onto dust grains. In such environments, the N2D+/N2H+ ratio can exceed the elemental abundance ratio of D/H by a factor of 104. Furthermore this ratio is very temperature dependent, and therefore the deuterium fractionation can be used to investigate the evolutionary state of Class 0 protostars.
We observed lines of N2H+, N2D+, C18O and HCO+ in a sample of 20 Class 0 and Class 0/I protostars. We determined the deuteration fraction and searched for correlations between the N2D+/N2H+ ratio and well-established evolutionary tracers, such as TDust and the CO depletion factor, and compared the ratio with results of a chemical model. We found a clear correlation between the N2D+/N2H+ ratio and evolutionary tracers. As expected, the coolest, i.e. the youngest, objects show the largest deuterium fractionation. Furthermore, we find that sources with a high N2D+/N2H+ ratio show clear indications of infall (e.g. dv < 0). With decreasing deuterium fraction, the infall signature disappears and δv tends to be positive for the most evolved objects.
The N2D+/N2H+ ratio is known to trace the evolution of prestellar cores. We show that this ratio can be used to trace core evolution even after star formation. Protostars with an N2D+/N2H+ ratio above 0.15 are in a stage shortly after the beginning of the collapse. Later on, deuterium fractionation decreases until it reaches a value of ˜0.03 at the Class 0/I borderline.
The deuterium fractionation of N2H+ has been compared with the deuterium fractionation of other molecules. The NH2D/NH3 is very similar to the N2D+/N2H+ ratio, whereas the DCO+/HCO+ ratio is low at all evolutionary stages.
No associations
LandOfFree
Deuterium Fractionation As Evolutionary Tracer Of Class 0 Protostars 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 Deuterium Fractionation As Evolutionary Tracer Of Class 0 Protostars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Deuterium Fractionation As Evolutionary Tracer Of Class 0 Protostars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1106388