CO Depletion and Deuterium Fractionation in Prestellar Cores

By A. Bacmann, Bertrand Lefloch, C. Ceccarelli, J. Steinacker, A. Castets, Laurent Loinard Eso Garching, A. Jena, Observatoire de Grenoble, O. Bordeaux, U. Mexico. 2003

152 citations recorded by the source corpus.

We report the detection of D2CO in a sample of starless dense cores, in which we previously measured the degree of CO depletion. The deuterium fractionation is found to be extremely high, [D2CO]/[H2CO] ~ 1%-10%, similar to that reported in low-mass protostars. This provides convincing evidence that D2CO is formed in the cold prestellar cores and later desorbed when the gas warms up in protostars. We find that the cores with the highest CO depletions have also the largest [D2CO]/[H2CO] ratios, supporting the theoretical prediction that deuteration increases with increasing CO depletion.

Subfields: Astronomy and Astrophysics, Inorganic Chemistry, Organic Chemistry

View Paper: https://www.semanticscholar.org/paper/3e8db477a168c8d0b91d601cbe1bd4103514f822

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. P. Caselli
2. E. Herbst
3. Cecilia Ceccarelli
4. M. Tafalla
5. E. Dishoeck
6. H. Roberts
7. R. Garrod
8. P. Myers

In Inorganic Chemistry

1. E. Herbst
2. H. Roberts
3. E. Dishoeck

In Organic Chemistry

1. A. Tielens
2. P. Caselli
3. Cecilia Ceccarelli
4. E. Dishoeck
5. P. Myers
6. E. Herbst

Citations in the corpus

• The chemistry of multiply deuterated species in cold, dense interstellar cores (2004, background): “One of the strongest pieces of evidence linking freeze-out with high deuteration is the study by Bacmann et al. (2003) of CO depletion and D2CO fractionation in pre-stellar cores.”
• First detection of triply-deuterated methanol (2003, background): “Meantime, observations of doubly deuterated formaldehyde in a sample of pre-stellar cores showed that the degree of deuteration increases with increasing CO depletion (Bacmann et al. 2002, 2003).”
• Molecular Evolution in Collapsing Prestellar Cores. III. Contraction of a Bonnor-Ebert Sphere (2004, background): “…multi-deuterated species have been detected in prestellar and protostellar cores, and their relative abundances to normal isotopomers, known as D/H ratios, found to be very high (10−3 − 10−1) (van der Tak et al. 2002; Lis et al. 2002; Parise et al. 2002; Bacmann et al. 2003; Parise et al. 2004).”
• Our astrochemical heritage (2012, background): “HDCO, D2CO and CH2DOH have been detected in prestellar cores (Bacmann et al. 2003; Bergman et al. 2011), while doubly and triply deuterated methanol have been detected in the envelope of young stellar objects (Parise et al.”
• Enhanced Deuterium Fractionation in Dense Interstellar Cores Resulting from Multiply Deuterated H3+ (2003, methodology): “The prestellar cores observed by Bacmann et al. (2002, 2003) indicate that D2CO fractionation increases with CO depletion.”
• Complex Molecules in the Hot Core of the Low-Mass Protostar NGC 1333 IRAS 4A (2004, background): “…fully hydrogenated molecules on the grain surfaces, has been demonstrated to occur in low mass protostars too, for example by studies of multiply deuterated molecules: formaldehyde (Ceccarelli et al. 1998, Bacmann et al. 2003), methanol (Parise et al. 2002, 2004) and sulfide (Vastel et al. 2003).”
• Cold Dark Clouds: The Initial Conditions for Star Formation (2007, unknown): “9; Stark et al. 1999; Aikawa et al. 2001; Bacmann et al. 2003).”
• Detection of complex organic molecules in a prestellar core: a new challenge for astrochemical models (2012, background): “It was selected based on the assumption that the gas-phase abundances of C-bearing molecules such as formaldehyde (Bacmann et al. 2003) or methanol (Bacmann et al., in prep.) were relatively large with respect to other cores.”
• Testing grain surface chemistry : a survey of deuterated formaldehyde and methanol in low-mass Class 0 protostars (2006, background): “A strong support to this scheme comes from the large abundance of D2CO observed in prestellar cores (Bacmann et al. 2003), and from the discovery of the large fractionation of H+3 in the same objects (Caselli et al. 2003; Vastel et al. 2004).”
• Probing the Evolutionary Status of Starless Cores through N2H+ and N2D+ Observations (2004, methodology): “As in Bacmann et al. (2003), Oph D seems to have ‘‘too much’’ deuterium fractionation compared to the CO depletion.”
• Molecular inventories and chemical evolution of low-mass protostellar envelopes (2003, background): “Other studies indicate an increase of the deuteration with CO depletion, e.g., the survey of the deuteration of D2CO for a sample of pre-stellar cores by Bacmann et al. (2003).”