The puzzling deuteration of methanol in low- to high-mass protostars

Ratajczak, A.; Taquet, V.; Kahane, C.; Ceccarelli, C.; Fauré, Alexandre; Quirico, E.

doi:10.1051/0004-6361/201016402

Cited by 46 publications

(62 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(A4) of Caselli et al (2002) from one transition only assuming optically thin conditions and adopting the rotation temperature derived from CH 3 OH, available in all sources as excitation temperature. The partition functions of all species have been calculated from the approximated expressions valid for asymmetric rotors provided, e.g., in Ratajczak et al (2011;see also Parise 2004). The results of this analysis are presented in Table 8.…”

Section: Derivation Of Molecular Column Densities and Rotation Tempermentioning

confidence: 99%

Deuteration and evolution in the massive star formation process

Fontani

Busquet

Palau

et al. 2015

A&A

131

View full text Add to dashboard Cite

Context. An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D and its hydrogenated counterpart, D frac ) is an evolutionary indicator both in the low-and the highmass star formation process. However, the role of surface chemistry in these studies has not been quantified from an observational point of view. Aims. Because many abundant species, such as NH 3 , H 2 CO, and CH 3 OH, are actively produced on ice mantles of dust grains during the early cold phases, their D frac is expected to evolve differently from species formed only (or predominantly) in the gas, such as N 2 H + , HNC, HCN, and their deuterated isotopologues. The differences are expected to be relevant especially after the protostellar birth, in which the temperature rises, causing the evaporation of ice mantles. Methods. To compare how the deuterated fractions of species formed only in the gas and partially or uniquely on grain surfaces evolve with time, we observed rotational transitions of CH 3 OH, 13 CH 3 OH, CH 2 DOH, and CH 3 OD at 3 mm and 1.3 mm, of NH 2 D at 3 mm with the IRAM-30 m telescope, and the inversion transitions (1, 1) and (2, 2) of NH 3 with the GBT, towards most of the cores already observed in N 2 H + , N 2 D + , HNC, and DNC. Results. NH 2 D is detected in all but two cores, regardless of the evolutionary stage. D frac (NH 3 ) is on average above 0.1 and does not change significantly from the earliest to the most evolved phases, although the highest average value is found in the protostellar phase (∼0.3). Few lines of CH 2 DOH and CH 3 OD are clearly detected, and then only towards protostellar cores or externally heated starless cores. In quiescent starless cores, we have only one doubtful detection of CH 2 DOH. Conclusions. This work clearly confirms an expected different evolutionary trend of the species formed exclusively in the gas (N 2 D + and N 2 H + ) and those formed partially (NH 2 D and NH 3 ) or totally (CH 2 DOH and CH 3 OH) on grain mantles. It also reinforces the idea that D frac (N 2 H + ) is the best tracer of massive starless cores, while high values of D frac (CH 3 OH) seem fairly good tracers of the early protostellar phases, where the evaporation or sputtering of the grain mantles is most efficient.

show abstract

Section: Derivation Of Molecular Column Densities and Rotation Tempermentioning

confidence: 99%

Deuteration and evolution in the massive star formation process

Fontani

Busquet

Palau

et al. 2015

A&A

131

View full text Add to dashboard Cite

show abstract

“…This is used to determine the formation pathway as shown by Cazaux et al (2011) and Coutens et al (2012), with the formation of water and formaldehyde. However, the process could be similar for hot cores, as shown by Turner (1990) or recently by Ratajczak et al (2011). Therefore we recently made extensive laboratory measurements to be able to search for the millimeter-wave spectrum of D-isotopologues of glycolaldehyde in the ISM.…”

Section: Introductionmentioning

confidence: 99%

The submillimeter spectrum of deuterated glycolaldehydes

Bouchez

Margulès

Motiyenko

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

Context. Glycolaldehyde, a sugar-related interstellar prebiotic molecule, has recently been detected in two star-forming regions, Sgr B2(N) and G31.41+0.31. The detection of this new species increased the list of complex organic molecules detected in the interstellar medium (ISM) and adds another level to the chemical complexity present in space. Besides, this kind of organic molecule is important because it is directly linked to the origin of life. For many years, astronomers have been struggling to understand the origin of this high chemical complexity in the ISM. The study of deuteration may provide crucial hints. Aims. In this context, we have measured the spectra of deuterated isotopologues of glycolaldehyde in the laboratory: the three monodeuterated ones (CH 2 OD-CHO, CHDOH-CHO and CH 2 OH-CDO) and one dideuterated derivative (CHDOH-CDO) in the ground vibrational state. Methods. Previous laboratory work on the D-isotopologues of glycolaldehyde was restricted to less than 26 GHz. We used a solidstate submillimeter-wave spectrometer in Lille with an accuracy for isolated lines better than 30 kHz to acquire new spectroscopic data between 150 and 630 GHz and employed the ASFIT and SPCAT programs for analysis. Results. We measured around 900 new lines for each isotopologue and determined spectroscopic parameters. This allows an accurate prediction in the ALMA range up to 850 GHz. Conclusions. This treatment meets the needs for a first astrophysical research, for which we provide an appropriate set of predictions.

show abstract

“…For methanol the abundance ratio of the deuterated isotopologues, [CH 2 DOH]/[CH 3 OD], is predicted to be about three (Charnley et al 1997). However, this ratio has been observed to lie in the range 5 to 30 towards low-mass and intermediate protostars (Parise et al 2006;Ratajczak et al 2011) and close to or below one in high-mass protostars (Ratajczak et al 2011). Recent laboratory studies (Nagaoka et al 2005;Ratajczak et al 2009) have shown that a much lower abundance of CH 3 OD than for CH 2 DOH, as observed in low-and intermediate-mass protostars (Ratajczak et al 2011), can be qualitatively explained via H/D exchanges occurring on the grain surface following methanol formation.…”

Section: Introductionmentioning

confidence: 99%

“…As a result, in the case of formamide, DCONH 2 species should be significantly more abundant than HCONDH and HCONHD ones, if solid H/D exchanges do happen, because these should take place on the amino group -ND 2 . On the other hand, the three deuterated isotopologues of formamide could have a similar abundance owing to some alternative or additional mechanisms in the postevaporative gas phase, as discussed for methanol by Ratajczak et al (2011). A&A 549, A128 (2013) Formamide is a small molecule with relatively light molecular weight (M = 44) and with non-zero μ a = 3.62 D and μ b = 0.85 D dipole moment components (Kurland & Wilson 1957).…”

Section: Introductionmentioning

confidence: 99%

The extended spectroscopic database for deuterated species of formamide up to 1 THz

Kutsenko

Motiyenko

Margulès

et al. 2013

A&A

View full text Add to dashboard Cite

Context. Formamide (HCONH 2 ) is the simplest molecule with a peptide bond detected in the interstellar medium. One of the keys for understanding the mechanisms for forming formamide in massive hot cores is the comparison of the relative abundances of its deuterated isotopologues. Aims. No deuterated species of formamide have been detected to date mostly owing to the lack of laboratory spectral data, which is limited by cm-wave measurements up to 40 GHz. Therefore, we decided to extend the measurements and the analysis of the rotational spectra of deuterated istopologues of formamide into the terahertz range. Methods. We measured the rotational spectra of deuterated formamide in the frequency range 150-950 GHz using the Lille fast-scan and solid-state source spectrometers. Results. The ground vibrational states of 4 different isotopologues of formamide, DCONH 2 , cis-HCONHD, trans-HCONHD, and HCOND 2 , were assigned and analysed. The sets of the rotational and centrifugal distortion constants we obtained allow us to calculate accurate predictions of the transition frequencies for deuterated formamide in the frequency range above 1 THz and at least for J < 65 and K a < 25.

show abstract

The puzzling deuteration of methanol in low- to high-mass protostars

Cited by 46 publications

References 21 publications

Deuteration and evolution in the massive star formation process

Deuteration and evolution in the massive star formation process

The submillimeter spectrum of deuterated glycolaldehydes

The extended spectroscopic database for deuterated species of formamide up to 1 THz

Contact Info

Product

Resources

About