Observations of CH<sub>3</sub>OH and CH<sub>3</sub>CHO in a Sample of Protostellar Outflow Sources

Holdship, Jonathan; Viti, S.; Codella, C.; Rawlings, J. M. C.; Jiménez-Serra, I.; Ayalew, Yenabeb; Curtis, Justin; Habib, Annur; Lawrence, Jamel; Warsame, Sumaya; Horn, Sarah R.

doi:10.3847/1538-4357/ab1f8f

Cited by 26 publications

(24 citation statements)

References 33 publications

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“…We attribute this difference to the fact that the single-dish observations of IRAS 4A by Holdship et al (2019) include emission from a much larger region (including some from the central protostars) with respect to that probed by the present SOLIS observations. Moreover Holdship et al (2019) do not explicitly derive the emitting size, even though they minimize with respect to this parameter; since the maximization is done independently for each species, their column density ratio has a relatively large intrinsic uncertainty. Therefore, the interferometric images allow us to minimize the risk of mixing different gas components (typical of shocked regions).…”

Section: Moleculementioning

confidence: 59%

“…Unfortunately, there are very few observations of iCOMs in low-mass protostellar shocks. To our knowledge, iCOMs other than methanol have been detected only toward a handful of objects: several iCOMs toward L1157-B1 (Arce et al 2008;Lefloch et al 2017), formamide toward L1157-B2 (Mendoza et al 2014), acetaldehyde toward IRAS 2A and IRAS 4A (Holdship et al 2019), and acetaldehyde and dimethyl ether toward SMM4-W (Öberg et al 2011). However, it is worth noting that all these works refer to single-dish observations at relatively low spatial angular resolution and are, by definition, unable to disentangle the different spatial distribution of iCOMs caused by the age of the shocks, so that the method described above cannot be used.…”

Section: Introductionmentioning

confidence: 99%

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Seeds of Life in Space (SOLIS)

Simone

Codella

Ceccarelli

et al. 2020

A&A

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Context. The interstellar complex organic molecules (iCOMs) are C-bearing molecules containing at least six atoms; two main proposals for their formation are suggested: a direct formation in the icy mantle of the dust grains and formation through the reaction in gas phase of released grain mantle species. The shocked gas along outflows driven by low-mass protostars is a unique environment to study how the iCOMs can be formed as the composition of the dust mantles is sputtered into the gas phase. Aims. The chemical richness in shocked material associated with low-mass protostellar outflows has been so far studied in the prototypical L1157 blue-shifted outflow to investigate the iCOM formation routes. To understand whether the case of L1157-B1 is unique, we imaged and studied the IRAS 4A outflows in the NGC 1333 star forming region. Methods. We used the NOrthern Extended Millimeter Array interferometer as part of the IRAM Seeds Of Life in Space (SOLIS) Large Program to image the large-scale bipolar outflows driven by the IRAS 4A system in the 3 mm band, and we compared the observation with the GRAINOBLE+ astrochemical model. Results. We report the first detection, in the IRAS 4A outflows, of several iCOMs: six lines of methanol (CH3OH), eight of acetaldehyde (CH3CHO), one of formamide (NH2CHO), and four of dimethyl ether (CH3OCH3), all sampling upper excitation energy up to ~30 K. We found a significant chemical differentiation between the southeast outflow driven by the IRAS 4A1 protostar, showing a richer molecular content, and the north–southwest one driven by the IRAS 4A2 hot corino. The CH3OH/CH3CHO abundance ratio is lower by a factor of ~4 in the former; furthermore, the ratio in the IRAS 4A outflows is lower by a factor of ~10 with respect to the values found in different hot corinos. Conclusions. After L1157-B1, the IRAS 4A outflow is now the second outflow to show an evident chemical complexity. Given that CH3OH is a grain surface species, the astrochemical gas-phase model run with GRAINOBLE+ reproduced our observation assuming that acetaldehyde is formed mainly through the gas-phase reaction of the ethyl radical (CH3CH2) and atomic oxygen. Furthermore, the chemical differentiation between the two outflows suggests that the IRAS 4A1 outflow is likely younger than that of the IRAS 4A2. Further investigation is needed to constrain the age of the outflow. In addition, observation of even younger shocks are necessary. In order to provide strong constraints on the CH3CHO formation mechanisms it would be interesting to observe CH3CH2, but given that its frequencies are not known, future spectroscopic studies on this species are needed.

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Section: Moleculementioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Seeds of Life in Space (SOLIS)

Simone

Codella

Ceccarelli

et al. 2020

A&A

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“…Original Research By Young Twinkle Students (ORBYTS) is an educational programme in which secondary school pupils work on original research linked to the Twinkle Space Mission under the tuition of PhD students and other young scientists (McKemmish et al 2017a). Previous projects have included calculating accurate molecular transition frequencies (Chubb et al 2018;McKemmish et al 2017b;Darby-Lewis et al 2019), studying planetary aurorae (Wibisono et al 2020) and spectral studies of the composition of protostellar regions (Holdship et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Original Research by Young Twinkle Students (ORBYTS): ephemeris refinement of transiting exoplanets

Edwards

Anisman

Changeat

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or have not been observed for over three years. A fully robotic ground-based telescope network, observations from citizen astronomers and data from TESS have been used to study eight planets, refining their ephemeris and orbital data. Such follow-up observations are key for ensuring accurate transit times for upcoming ground and space-based telescopes which may seek to characterise the atmospheres of these planets. We find deviations from the expected transit time for all planets, with transits occurring outside the 1 sigma uncertainties for seven planets. Using the newly acquired observations, we subsequently refine their periods and reduce the current predicted ephemeris uncertainties to 0.28 - 4.01 minutes. A significant portion of this work has been completed by students at two high schools in London as part of the Original Research By Young Twinkle Students (ORBYTS) programme.

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“…Large COM species, such as propylene (CH 2 CHCH 3 ), acetaldehyde (CH 3 CHO), dimethyl ether (CH 3 OCH 3 ), or methyl formate (CH 3 OCHO), have been found in the gas-phase toward dark cloud cores and starless/prestellar cores (Marcelino et al 2007;Öberg et al 2010;Bacmann et al 2012;Cernicharo et al 2012;Vastel et al 2014;Jiménez-Serra et al 2016;Soma et al 2018;Agúndez et al 2019;Yoshida et al 2019;Scibelli & Shirley 2020). These observations have triggered a plethora of theoretical and experimental studies to understand COM formation at low temperatures (see e.g., Rawlings et al 2013;Vasyunin & Herbst 2013;Balucani et al 2015;Ivlev et al 2015;Ruaud et al 2015;Chuang et al 2016;Quénard et al 2018;Shingledecker et al 2018;Holdship et al 2019;Jin & Garrod 2020), although no consensus has been reached yet.…”

Section: Introductionmentioning

confidence: 99%

The Complex Organic Molecular Content in the L1498 Starless Core

Jiménez-Serra

Vasyunin

Spezzano

et al. 2021

ApJ

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Observations carried out toward starless and prestellar cores have revealed that complex organic molecules are prevalent in these objects, but it is unclear what chemical processes are involved in their formation. Recently, it has been shown that complex organics are preferentially produced at an intermediate-density shell within the L1544 prestellar core at radial distances of ∼4000 au with respect to the core center. However, the spatial distribution of complex organics has only been inferred toward this core, and it remains unknown whether these species present a similar behavior in other cores. We report high-sensitivity observations carried out toward two positions in the L1498 starless core, the dust peak and a position located at a distance of ∼11,000 au from the center of the core where the emission of CH 3 OH peaks. Similarly to L1544, our observations reveal that small O-bearing molecules and N-bearing species are enhanced by factors of ∼4-14 toward the outer shell of L1498. However, unlike L1544, large O-bearing organics such as CH 3 CHO, CH 3 OCH 3 , or CH 3 OCHO are not detected within our sensitivity limits. For N-bearing organics, these species are more abundant toward the outer shell of the L1498 starless core than toward the one in L1544. We propose that the differences observed between O-bearing and N-bearing species in L1498 and L1544 are due to the different physical structure of these cores, which in turn is a consequence of their evolutionary stage, with L1498 being younger than L1544.

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Observations of CH₃OH and CH₃CHO in a Sample of Protostellar Outflow Sources

Cited by 26 publications

References 33 publications

Seeds of Life in Space (SOLIS)

Seeds of Life in Space (SOLIS)

Original Research by Young Twinkle Students (ORBYTS): ephemeris refinement of transiting exoplanets

The Complex Organic Molecular Content in the L1498 Starless Core

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Observations of CH3OH and CH3CHO in a Sample of Protostellar Outflow Sources

Cited by 26 publications

References 33 publications

Seeds of Life in Space (SOLIS)

Seeds of Life in Space (SOLIS)

Original Research by Young Twinkle Students (ORBYTS): ephemeris refinement of transiting exoplanets

The Complex Organic Molecular Content in the L1498 Starless Core

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Product

Resources

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Observations of CH₃OH and CH₃CHO in a Sample of Protostellar Outflow Sources