E. R. Willis's scientific contributions

Publications (10)

Article
Context. The Exploring Molecule Complexity with ALMA (EMoCA) survey is an imaging spectral line survey using the Atacama Large Millimeter/submillimeter Array (ALMA) to study the hot-core complex Sagittarius B2(N). Recently, EMoCA revealed the presence of three new hot cores in this complex (N3-N5), in addition to providing detailed spectral data on...
Preprint
We used the EMoCA survey data to search for isocyanides in Sgr B2(N2) and their corresponding cyanide analogs. We then used the coupled three-phase chemical kinetics code MAGICKAL to simulate their chemistry. Several new species, and over 100 new reactions have been added to the network. In addition, a new single-stage simultaneous collapse/warm-up...
Article
Context. Propyne (CH 3 CCH), also known as methyl acetylene, has been detected in a variety of environments, from Galactic star-forming regions to extragalactic sources. These molecules are excellent tracers of the physical conditions in star-forming regions, allowing the temperature and density conditions surrounding a forming star to be determine...
Preprint
Context. Propyne (CH$_3$CCH) has been detected in a variety of environments, from Galactic star-forming regions to extragalactic sources. Such molecules are excellent tracers of the physical conditions in star-forming regions. Aims. This study explores the emission of CH$_3$CCH in the low-mass protostellar binary, IRAS 16293$-$2422, examining the s...
Article
Full-text available
Context. As the number of complex organic molecules (COMs) detected in the interstellar medium increases, it becomes even more important to place meaningful constraints on the origins and formation pathways of such chemical species. The molecular cloud Sagittarius B2(N) is host to several hot molecular cores in the early stage of star formation, wh...
Preprint
As the number of complex organic molecules (COMs) detected in the interstellar medium increases, it becomes important to place meaningful constraints on the formation pathways of these species. The molecular cloud SgrB2(N) is host to several hot molecular cores in the early stage of star formation, where a great variety of COMs are detected in the...
Article
Context. Methyl isocyanide (CH 3 NC) is the isocyanide with the largest number of atoms confirmed in the interstellar medium (ISM), but it is not an abundant molecule, having only been detected towards a handful of objects. Conversely, its isomer, methyl cyanide (CH 3 CN), is one of the most abundant complex organic molecules detected in the ISM, w...
Preprint
Methyl isocyanide (CH$_3$NC) is the isocyanide with the largest number of atoms confirmed in the interstellar medium (ISM), but it is not an abundant molecule, having only been detected towards a handful of objects. Conversely, its isomer, methyl cyanide (CH$_3$CN), is one of the most abundant complex organic molecules detected in the ISM, with det...
Article
Full-text available
Searches for the prebiotically-relevant cyanamide (NH$_2$CN) towards solar-type protostars have not been reported in the literature. We here present the first detection of this species in the warm gas surrounding two solar-type protostars, using data from the Atacama Large Millimeter/Submillimeter Array Protostellar Interferometric Line Survey (PIL...

Citations

... However, as like Belloche et al. (2014); Garrod et al. (2017), none of our models were successful in obtaining such a high abundance with the present reaction network. It might be due to the exceptional environment in the Galactic center region than the other not core as discussed in Bonfand et al. (2019); Willis et al. (2020). The i/n abundance ratio for set 1 with low activation barriers vary between 1 and 1.2 (see Fig. 7). ...
... Through the observation of molecular emission lines, it is possible to constrain both the physical conditions and the chemical evolution of circumstellar sources, shedding light on the formation processes that connect different evolutionary stages of star-formation. Methyl acetylene (CH 3 CCH), also known as propyne, is a particularly good temperature probe, and has therefore been widely explored toward various star-forming objects (e.g., Fontani et al. 2002;Bisschop et al. 2007;Fayolle et al. 2015;Giannetti et al. 2017;Andron et al. 2018;Calcutt et al. 2019). ...
... A recent observational study of the protostellar binary IRAS 16293−2422 with ALMA [34] found only evidence for propyne in the hot corinos, the warmer and denser parts of the molecular clouds surrounding the protostars. The rotational temperatures of ∼100 K appear to be typical for propyne and several other molecules in such environments. ...
... This similarity is very striking when we consider that the physical conditions of collected sources vary significantly, 0.16-47 L e and 0.12-32 L e for hot corinos from CALYPSO ) and PEACHES (Yang et al. 2021), 3 L e for IRAS 16293B (Jacobsen et al. 2018), 9 L e for the low-mass disk-harboring protostar in HH 212 (Lee et al. 2019a), 200 L e for bursting protostar V883 Ori (White et al. 2019), and ∼2 × 10 5 L e for hot cores AFGL 4167 and Sgr B2(N2) (Bøgelund et al. 2019;Bonfand et al. 2019). The fact that over an order of magnitude range in abundance is detected in huge luminosity differences over 6 orders of magnitude indicates that the current luminosity is not a dominant factor affecting the characteristics of COMs. ...
... In contrast to the numerous detection of cyanides in astronomical environments, there have been very few confirmed detection of isocyanides, such as methyl isocyanide (CH 3 NC) (Remijan et al. 2005;Gratier et al. 2013). Most recently, the Protostellar Interferometric Line Survey (PILS) observed CH 3 NC in a solar-type star, IRAS 16293-2422, for the first time toward a source of this type (Calcutt et al. 2018). Despite that, there have been no successful detections of CH 2 CHCH 2 NC (Haykal et al. 2013) or CH 3 CH 2 NC (Remijan et al. 2005;Margulès et al. 2018). ...
... The deuterated species detected in the PILS data are the mono-deuterated isotopomers of the oxygen-bearing organics glycolaldehyde (Jørgensen et al. 2016), ethanol, ketene, formic acid and of mono-deuterated acetaldehyde species CH 3 CDO (Jørgensen et al. 2018) and CH 2 DCHO (Coudert et al. 2019;Manigand et al. 2020), of the nitrogenbearing organics isocyanic acid DNCO and the monodeuterated isotopomers of formamide (Coutens et al. 2016) and the cyanamide isotopologue HDNCN (Coutens et al. 2018) and sulfur-containing species such as the hydrogen sulfide isotopologue HD 34 S (Drozdovskaya et al. 2018). Also, the PILS data reveal the presence of doubly-deuterated organics including the methyl cyanide species CHD 2 CN (Calcutt et al. 2018), the methyl formate species CHD 2 OCHO (Manigand et al. 2019) and the dimethyl ether species CHD 2 OCH 3 (Richard et al. 2021) and enable new and more accurate constraints on the doubly-and triply-deuterated variants of methanol in the warm gas close to the protostars (Drozdovskaya et al. 2022;Ilyushin et al. 2022). ...