Distribution of methanol and cyclopropenylidene around starless cores

Spezzano, S.; Caselli, P.; Pineda, Jaime E.; Bizzocchi, L.; Prudenzano, Domenico; Nagy, Z.

doi:10.1051/0004-6361/201936598

Cited by 23 publications

(23 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous work on emission maps of methanol towards four starless and two pre-stellar cores suggested that the asymmetric distribution of methanol is linked to the large scale density structure around the cores as well as different amount of illumination from the external radiation field (Spezzano et al 2016(Spezzano et al , 2020. With this work we can confirm that environmental effects have a strong impact on the methanol distribution.…”

Section: Discussionsupporting

confidence: 69%

“…in L1544 as shown in Bizzocchi et al 2014;Vastel et al 2014). Furthermore, the emission of methanol is not homogeneous around pre-stellar and starless cores, and its distribution has been shown to depend on the density structure around the core, and hence the illumination onto the core due to the interstellar radiation field (Spezzano et al 2016(Spezzano et al , 2020. In Spezzano et al (2016), for example, the emission maps of methanol and cyclopropenylidene towards the inner 2.5 × 2.5 of the pre-stellar core L1544 show that both molecules have asymmetric distribution around the core, with methanol peaking towards the north-east and cyclopropenylidene towards the south-west.…”

Section: Resultsmentioning

confidence: 97%

“…In addition to the density structure around the core, also larger scale environmental effects have shown to influence the distribution of methanol around starless and pre-stellar cores. In Spezzano et al (2020), methanol was mapped towards four pre-stellar and two starless cores, and it was shown that the methanol peak was influenced by the presence of nearby massive stars in the two cores mapped in Ophiucus (OphD and HMM-1).…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus

Spezzano

Fuente

Caselli

et al. 2021

A&A

Self Cite

View full text Add to dashboard Cite

Context. Methanol, one of the simplest complex organic molecules in the interstellar medium, has been shown to be present and extended in cold environments such as starless cores. Studying the physical conditions at which CH3OH starts its efficient formation is important to understand the development of molecular complexity in star-forming regions. Aims. We aim to study methanol emission across several starless cores and investigate the physical conditions at which methanol starts to be efficiently formed, as well as how the physical structure of the cores and their surrounding environment affect its distribution. Methods. Methanol and C18O emission lines at 3 mm have been observed with the IRAM 30 m telescope within the large programme Gas phase Elemental abundances in Molecular CloudS towards 66 positions across 12 starless cores in the Taurus Molecular Cloud. A non-LTE (local thermodynamic equilibrium) radiative transfer code was used to compute the column densities in all positions. We then used state-of-the-art chemical models to reproduce our observations. Results. We have computed N(CH3OH)/N(C18O) column density ratios for all the observed offsets, and the following two different behaviours can be recognised: the cores where the ratio peaks at the dust peak and the cores where the ratio peaks with a slight offset with respect to the dust peak (~10 000 AU). We suggest that the cause of this behaviour is the irradiation on the cores due to protostars nearby which accelerate energetic particles along their outflows. The chemical models, which do not take irradiation variations into account, can reproduce the overall observed column density of methanol fairly well, but they cannot reproduce the two different radial profiles observed. Conclusions. We confirm the substantial effect of the environment on the distribution of methanol in starless cores. We suggest that the clumpy medium generated by protostellar outflows might cause a more efficient penetration of the interstellar radiation field in the molecular cloud and have an impact on the distribution of methanol in starless cores. Additional experimental and theoretical work is needed to reproduce the distribution of methanol across starless cores.

show abstract

Section: Discussionsupporting

confidence: 69%

Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus

Spezzano

Fuente

Caselli

et al. 2021

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…1). The n3 position is located at the northern edge of NGC 2264-D and the integrated intensity ratio of HC 3 N and CH 3 OH, I(HC 3 N)/I(CH 3 OH), at this position shows the highest value among the other positions in NGC 2264-C and NGC 2264-D. A variety in the I(HC 3 N)/I(CH 3 OH) ratio implies a chemical differentiation in the clusterforming region, suggestive of different evolutionary histories and/or different environments (Spezzano et al 2016;Taniguchi et al 2019a;Spezzano et al 2020). The n3 position is located to the west of the IRS2 source (IRAS 06382+0939).…”

mentioning

confidence: 90%

Clump-scale chemistry in the NGC2264-D cluster-forming region

Taniguchi,

Plunkett,

Shimoikura

et al. 2021

Preprint

View full text Add to dashboard Cite

We have conducted mapping observations toward the n3 and n5 positions in the NGC 2264-D cluster-forming region with the Atacama Compact Array (ACA) of the Atacama Large Millimeter/submillimeter Array (ALMA) in Band 3. Observations with 10000 au scale beam reveal the chemical composition at the clump scale. The spatial distributions of the observed low upper-state-energy lines of CH 3 OH are similar to those of CS and SO, and the HC 3 N emission seems to be predominantly associated with clumps containing young stellar objects. The turbulent gas induced by the star formation activities produces large-scale shock regions in NGC 2264-D, which are traced by the CH 3 OH, CS and SO emissions. We derive the HC 3 N, CH 3 CN, and CH 3 CHO abundances with respect to CH 3 OH. Compared to the n5 field, the n3 field is farther (in projected apparent distance) from the neighboring NGC 2264-C, yet the chemical composition in the n3 field tends to be similar to that of the protostellar candidate CMM3 in NGC 2264-C. The HC 3 N/CH 3 OH ratios in the n3 field are higher than those in the n5 field. We find an anti-correlation between the HC 3 N/CH 3 OH ratio and their excitation temperatures. The low HC 3 N/CH 3 OH abundance ratio at the n5 field implies that the n5 field is an environment with more active star formation compared with the n3 field.

show abstract

“…They found that CH 3 OH is abundant in a region well shielded against the interstellar radiation field, while cyclic-C 3 H 2 (hereafter c-C 3 H 2 ) is enhanced in the irradiated environment. Such a chemical differentiation implies a different chemical composition in ice mantles, as shown by the CH 4 /CH 3 OH ice-mantle abundance ratio (Spezzano et al 2016(Spezzano et al , 2020, because the gas-phase c-C 3 H 2 can be considered to form from CH 4 by the WCCC mechanism (Hassel et al 2008). The UV radiation destroys CO molecules forming carbon atoms (C), which lead to the CH 4 -rich ice, and finally the carbon-chain-rich gas.…”

Section: Introductionmentioning

confidence: 99%

Chemical compositions in the vicinity of protostars in Ophiuchus

Taniguchi,

Majumdar,

Plunkett

et al. 2021

Preprint

View full text Add to dashboard Cite

We have analyzed Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 4 Band 6 data toward two young stellar objects (YSOs), Oph-emb5 and Oph-emb9, in the Ophiuchus star-forming region. The YSO Oph-emb5 is located in a relatively quiescent region, whereas Oph-emb9 is irradiated by a nearby bright Herbig Be star. Molecular lines from cyclic-C 3 H 2 (c-C 3 H 2 ), H 2 CO, CH 3 OH, 13 CO, C 18 O, and DCO + have been detected from both sources, while DCN is detected only in Oph-emb9. Around Oph-emb5, c-C 3 H 2 is enhanced at the west side, relative to the IR source, whereas H 2 CO and CH 3 OH are abundant at the east side. In the field of Oph-emb9, moment 0 maps of the c-C 3 H 2 lines show a peak at the eastern edge of the field of view, which is irradiated by the Herbig Be star. Moment 0 maps of CH 3 OH and H 2 CO show peaks farther from the bright star. We derive the N (c-C 3 H 2 )/N (CH 3 OH) column density ratios at the peak positions of c-C 3 H 2 and CH 3 OH near each YSO, which are identified based on their moment 0 maps. The N (c-C 3 H 2 )/N (CH 3 OH) ratio at the c-C 3 H 2 peak is significantly higher than at the CH 3 OH peak by a factor of ∼ 19 in Oph-emb9, while the difference in this column density ratio between these two positions is a factor of ∼ 2.6 in Oph-emb5. These differences are attributed to the efficiency of the photon-dominated region (PDR) chemistry in Oph-emb9. The higher DCO + column density and the detection of DCN in Oph-emb9 are also discussed in the context of UV irradiation flux.

show abstract

Distribution of methanol and cyclopropenylidene around starless cores

Cited by 23 publications

References 46 publications

Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus

Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus

Clump-scale chemistry in the NGC2264-D cluster-forming region

Chemical compositions in the vicinity of protostars in Ophiuchus

Contact Info

Product

Resources

About