# S. F. Wampfler's research while affiliated with ETH Zurich and other places

## Publications (88)

Article
Ammonium hydrosulphide has long since been postulated to exist at least in certain layers of the giant planets. Its radiation products may be the reason for the red colour seen on Jupiter. Several ammonium salts, the products of NH3 and an acid, have previously been detected at comet 67P/Churyumov-Gerasimenko. The acid H2S is the fifth most abundan...
Preprint
Full-text available
Ammonium hydrosulphide has long since been postulated to exist at least in certain layers of the giant planets. Its radiation products may be the reason for the red colour seen on Jupiter. Several ammonium salts, the products of NH3 and an acid, have previously been detected at comet 67P/Churyumov-Gerasimenko. The acid H2S is the fifth most abundan...
Article
Full-text available
In-situ study of comet 1P/Halley during its 1986 apparition revealed a surprising abundance of organic coma species. It remained unclear, whether or not these species originated from polymeric matter. Now, high-resolution mass-spectrometric data collected at comet 67P/Churyumov-Gerasimenko by ESA’s Rosetta mission unveil the chemical structure of c...
Article
Context. Isotopic abundances in comets are key to understanding and reconstructing the history and origin of material in the Solar System. Data for deuterium-to-hydrogen (D/H) ratios in water are available for several comets. However, no long-term studies of the D/H ratio in water of a comet during its passage around the Sun have been reported thus...
Article
Context. In an earlier study, we reported that the ram gauge of the COmet Pressure Sensor (COPS), one of the three instruments of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA), could be used to obtain information about the sublimating content of icy particles, made up of volatiles and conceivably refractories coming from co...
Article
Context. Water is a key molecule in the physics and chemistry of star and planet formation, but it is difficult to observe from Earth. The Herschel Space Observatory provided unprecedented sensitivity as well as spatial and spectral resolution to study water. The Water In Star-forming regions with Herschel (WISH) key program was designed to observe...
Preprint
Full-text available
The cyano radical (CN) is one of the most frequently remotely observed species in space, also in comets. Data from the high-resolution Double Focusing Mass Spectrometer (DFMS) on board the Rosetta orbiter, collected in the inner coma of comet 67P/Churyumov-Gerasimenko, revealed an unexpected chemical complexity, and, recently, also more CN than exp...
Article
The cyano radical (CN) is one of the most frequently remotely observed species in space, and is also often observed in comets. Data for the inner coma of comet 67P/Churyumov-Gerasimenko collected by the high-resolution Double Focusing Mass Spectrometer (DFMS) on board the Rosetta orbiter revealed an unexpected chemical complexity, and, recently, al...
Preprint
The ratios of the three stable oxygen isotopes 16O, 17O and 18O on Earth and, as far as we know in the solar system, show variations on the order of a few percent at most, with a few outliers in meteorites. However, in the interstellar medium there are some highly fractionated oxygen isotopic ratios in some specific molecules. The goal of this work...
Article
Context. The ESA Rosetta mission has allowed for an extensive in situ study of the comet 67P/Churyumov-Gerasimenko. In measurements performed by the ram gauge of the COmet Pressure Sensor (COPS), observed features are seen to deviate from the nominal ram gauge signal. This effect is attributable to the sublimation of the volatile fraction of cometa...
Article
The ratios of the three stable oxygen isotopes 16O, 17O, and 18O on the Earth and, as far as we know in the Solar system, show variations on the order of a few per cent at most, with a few outliers in meteorites. However, in the interstellar medium there are some highly fractionated oxygen isotopic ratios in some specific molecules. The goal of thi...
Article
Context. Complex organic molecules with three carbon atoms are found in the earliest stages of star formation. In particular, propenal (C 2 H 3 CHO) is a species of interest due to its implication in the formation of more complex species and even biotic molecules. Aims. This study aims to search for the presence of C 2 H 3 CHO and other three-carbo...
Article
Full-text available
Context. Complex organic molecules with three carbon atoms are found in the earliest stages of star formation. In particular, propenal (C 2 H 3 CHO) is a species of interest due to its implication in the formation of more complex species and even biotic molecules. Aims. This study aims to search for the presence of C 2 H 3 CHO and other three-carbo...
Preprint
Complex organic molecules with three carbon atoms are found in the earliest stages of star formation. In particular, propenal (C$_2$H$_3$CHO) is a species of interest due to its implication in the formation of more complex species and even biotic molecules. This study aims to search for the presence of C$_2$H$_3$CHO and other three-carbon species s...
Article
Context. Complex organic molecules are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these species form remains an open question. Aims. This study aims to constrain the formation of complex organic molecules through comparisons of their abundances towards the Class 0 protostellar...
Preprint
Complex organic molecules (COM) are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these COM form remains an open question. This study aims to constrain the formation of complex organic molecules through comparisons of their abundances towards the Class 0 protostellar binary IRAS...
Preprint
Cometary comae are generally depleted in nitrogen. The main carriers for volatile nitrogen in comets are NH3 and HCN. It is known that ammonia readily combines with many acids like e.g. HCN, HNCO, HCOOH, etc. encountered in the interstellar medium as well as in cometary ice to form ammonium salts (NH4+X-) at low temperatures. Ammonium salts, which...
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$-$2422, examining the s...
Article
Context. Unlike all previous cometary space missions, the Rosetta spacecraft accompanied its target, comet 67P/Churyumov-Gerasimenko, for more than two years on its way around the Sun. Thereby, an unexpected diversity and complexity of the chemical composition was revealed. Aims. Our first step of decrypting the exact chemical composition of the ga...
Article
Context. The majority of stars form in binary or higher order systems. The evolution of each protostar in a multiple system may start at different times and may progress differently. The Class 0 protostellar system IRAS 16293–2422 contains two protostars, “A” and “B”, separated by ~600 au and embedded in a single, 10 ⁴ au scale envelope. Their rela...
Preprint
[Abridged] The majority of stars form in binary or higher order systems. The Class 0 protostellar system IRAS16293-2422 contains two protostars, 'A' and 'B', separated by ~600 au and embedded in a single, 10^4 au scale envelope. Their relative evolutionary stages have been debated. We aim to study the relation and interplay between the two protosta...
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Full-text available
Nitrogen oxides are thought to play a significant role as a nitrogen reservoir and to potentially participate in the formation of more complex species. Until now, only NO, NO, and HNO have been detected in the interstellar medium. We report the first interstellar detection of nitrous acid (HONO). Twelve lines were identified towards component B of...
Preprint
Full-text available
Nitrogen oxides are thought to play a significant role as a nitrogen reservoir and to potentially participate in the formation of more complex species. Until now, only NO, N$_2$O and HNO have been detected in the interstellar medium. We report the first interstellar detection of nitrous acid (HONO). Twelve lines were identified towards component B...
Article
Studies of deuterated isotopologues of complex organic molecules can provide important constraints on their origin in star formation regions. In particular, the abundances of deuterated species are very sensitive to the physical conditions in the environment where they form. Because the temperatures in star formation regions are low, these isotopol...
Preprint
Studies of deuterated isotopologues of complex organic molecules can provide important constraints on their origin in regions of star formation. In particular, the abundances of deuterated species are very sensitive to the physical conditions in the environment where they form. Due to the low temperatures in regions of star formation, these isotopo...
Article
It is not known whether the original carriers of Earth's nitrogen were molecular ices or refractory dust. To investigate this question, we have used data and results of Herschel observations toward two protostellar sources: the high-mass hot core of Orion KL, and the low-mass protostar IRAS 16293−2422. Toward Orion KL, our analysis of the molecular...
Article
Recent measurements carried out at comet 67P/Churyumov–Gerasimenko (67P) with the Rosetta probe revealed that molecular oxygen, O₂, is the fourth most abundant molecule in comets. Models show that O₂ is likely of primordial nature, coming from the interstellar cloud from which our solar system was formed. However, gaseous O₂ is an elusive molecule...
Preprint
It is not known whether the original carriers of Earth's nitrogen were molecular ices or refractory dust. To investigate this question, we have used data and results of Herschel observations towards two protostellar sources: the high-mass hot core of Orion KL, and the low-mass protostar IRAS 16293-2422. Towards Orion KL, our analysis of the molecul...
Article
Context. One of the important questions of astrochemistry is how complex organic molecules, including potential prebiotic species, are formed in the envelopes around embedded protostars. The abundances of minor isotopologues of a molecule, in particular the D- and ¹³ C-bearing variants, are sensitive to the densities, temperatures and timescales ch...
Preprint
This paper presents a systematic survey of the deuterated and 13C isotopologues of a variety of oxygen-bearing complex organic molecules on Solar System scales toward the protostar IRAS 16293-2422B. We use the data from an unbiased molecular line survey between 329 and 363 GHz from the Atacama Large Millimeter/submillimeter Array (ALMA). The observ...
Article
Context. Hydroxylamine (NH 2 OH) and methylamine (CH 3 NH 2 ) have both been suggested as precursors to the formation of amino acids and are therefore, of interest to prebiotic chemistry. Their presence in interstellar space and formation mechanisms, however, are not well established. Aims. We aim to detect both amines and their potential precursor...
Preprint
Hydroxylamine (NH$_{2}$OH) and methylamine (CH$_{3}$NH$_{2}$) have both been suggested as precursors to the formation of amino acids and are therefore of interest to prebiotic chemistry. Their presence in interstellar space and formation mechanisms, however, are not well established. We aim to detect both amines and their potential precursor molecu...
Article
Context. Methyl isocyanide (CH 3 NC) is the isocyanide with the largest number of atoms confirmed in the interstellar medium (ISM), but it is not an abundant molecule, having only been detected towards a handful of objects. Conversely, its isomer, methyl cyanide (CH 3 CN), is one of the most abundant complex organic molecules detected in the ISM, w...
Preprint
Methyl isocyanide (CH$_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...
Preprint
Recent measurements carried out at comet 67P/C-G with the ${\it Rosetta}$ probe revealed that molecular oxygen, O$_2$, is the fourth most abundant molecule in comets. Models show that O$_2$ is likely of primordial nature, coming from the interstellar cloud from which our Solar System was formed. However, gaseous O$_2$ is an elusive molecule in the...
Article
Context . Complex organic molecules are readily detected in the inner regions of the gaseous envelopes of forming protostars. Their detection is crucial to understanding the chemical evolution of the Universe and exploring the link between the early stages of star formation and the formation of solar system bodies, where complex organic molecules h...
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Full-text available
Complex organic molecules are readily detected in the inner regions of the gaseous envelopes of forming protostars. In particular, molecules that contain nitrogen are interesting due to the role nitrogen plays in the development of life and the compact scales such molecules have been found to trace around forming protostars. The goal of this work i...
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...
Article
Full-text available
Context. The Class 0 protostellar binary IRAS 16293–2422 is an interesting target for (sub)millimeter observations due to, both, the rich chemistry toward the two main components of the binary and its complex morphology. Its proximity to Earth allows the study of its physical and chemical structure on solar system scales using high angular resoluti...
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Context. The enhanced degrees of deuterium fractionation observed in envelopes around protostars demonstrate the importance of chemistry at low temperatures, relevant in pre- and protostellar cores. Formaldehyde is an important species in the formation of methanol and more complex molecules. Aims. Here, we aim to present the first study of formalde...
Article
Context. Measurements of isotopic abundances in cometary ices are key to understanding and reconstructing the history and origin of material in the solar system. Comets are considered the most pristine material in the solar system. Isotopic fractionation (enrichment of an isotope in a molecule compared to the initial abundance) is sensitive to envi...
Article
Full-text available
(Abridged) Through spectrally unresolved observations of high-J CO transitions, Herschel-PACS has revealed large reservoirs of warm (300 K) and hot (700 K) molecular gas around low-mass protostars. We aim to shed light on the excitation and origin of the CO ladder observed toward protostars, and on the water abundance in different physical componen...
Article
Context. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) was designed to measure the composition of the gas in the coma of comet 67P/Churyumov-Gerasimenko, the target of the European Space Agency's Rosetta mission. In addition to the volatiles, ROSINA measured refractories sputtered off the comet by the interaction of solar w...
Article
Full-text available
Methyl isocyanate (CH$_{3}$NCO) belongs to a select group of interstellar molecules considered to be relevant precursors in the formation of larger organic compounds, including those with peptide bonds. The molecule has only been detected in a couple of high-mass protostars and potentially in comets. A formation route on icy grains has been postula...
Article
Several sulphur-bearing species have already been observed in different families of comets. However, the knowledge on the minor sulphur species is still limited. The comet's sulphur inventory is closely linked to the presolar cloud and holds important clues to the degree of reprocessing of the material in the solar nebula and during comet accretion...
Article
The inner regions of the envelopes surrounding young protostars are characterised by a complex chemistry, with prebiotic molecules present on the scales where protoplanetary disks eventually may form. This paper introduces a systematic survey, "Protostellar Interferometric Line Survey (PILS)" of the Class 0 protostellar binary IRAS 16293-2422 using...
Article
Context. Hydrides are simple compounds containing one or a few hydrogen atoms bonded to a heavier atom. They are fundamental precursor molecules in cosmic chemistry and many hydride ions have become observable in high quality for the first time thanks to the Herschel Space Observatory. Ionized hydrides such as CH+ and OH+ (and also HCO+), which aff...
Article
Hydrides are simple compounds containing one or a few hydrogen atoms bonded to a heavier atom. They are fundamental precursor molecules in cosmic chemistry and many hydride ions have become observable in high quality for the first time thanks to the Herschel Space Observatory. Ionized hydrides, such as CH+ and OH+, and also HCO+ that affect the che...
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Full-text available
OH is a key molecule in H2O chemistry, a valuable tool for probing physical conditions, and an important contributor to the cooling of shock regions. OH participates in the re-distribution of energy from the protostar towards the surrounding ISM. Our aim is to assess the origin of the OH emission from the Cepheus A massive star-forming region and t...
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Protostars interact with their surroundings through jets and winds impacting on the envelope and creating shocks, but the nature of these shocks is still poorly understood. Our aim is to survey far-infrared molecular line emission from a uniform and significant sample of deeply-embedded low-mass young stellar objects in order to characterize shocks...
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(Abridged) The terrestrial planets, comets, and meteorites are significantly enriched in 15N compared to the Sun and Jupiter. While the solar and jovian nitrogen isotope ratio is believed to represent the composition of the protosolar nebula, a still unidentified process has caused 15N-enrichment in the solids. Several mechanisms have been proposed...
Article
Herschel-HIFI spectra of H2O towards low-mass protostars show a distinct velocity component not seen in observations from the ground of CO or other species. The aim is to characterise this component in terms of excitation conditions and physical origin. A velocity component with an offset of ~10 km/s detected in spectra of the H2O 110-101 557 GHz t...
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(Abridged) Far-infrared Herschel-PACS spectra of 18 low-mass protostars of various luminosities and evolutionary stages are studied. We quantify their far-infrared line emission and the contribution of different atomic and molecular species to the gas cooling budget during protostellar evolution. We also determine the spatial extent of the emission...
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OH is a key species in the water chemistry of star-forming regions, because its presence is tightly related to the formation and destruction of water. This paper presents OH observations from 23 low- and intermediate-mass young stellar objects obtained with the PACS integral field spectrometer on-board Herschel in the context of the Water In Star-f...
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We present the first complete 55-671 um spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers on board Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from J=4-3 to 42-41), H2O, OH, 13CO, HCN and HCO+ . Bright [OI]63,145um and weaker [C...
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(Abridged) Water is a key tracer of dynamics and chemistry in low-mass protostars, but spectrally resolved observations have so far been limited in sensitivity and angular resolution. In this first systematic survey of spectrally resolved water emission in low-mass protostellar objects, H2O was observed in the ground-state transition at 557 GHz wit...
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We present and analyze two spectrally resolved high-J CO lines towards the molecular outflow Cep E, driven by an intermediate-mass class 0 protostar. Using the GREAT receiver on board SOFIA, we observed the CO (12--11) and (13--12) transitions (E_u ~ 430 and 500 K, respectively) towards one position in the blue lobe of this outflow, that had been k...
Article
During the earliest embedded stages of low-mass star formation the protostar interacts with its surroundings through high-velocity shocks and UV radiation, providing feedback to the material from which the star forms. At the same time, in-falling gas is heated to several 100 K by the accretion luminosity. Each of these processes has the ability to...
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Full-text available
Water is a key molecule for tracing physical and chemical processes in star-forming regions. The key program "Water in star-forming regions with Herschel" is observing several water transitions towards low-mass protostars with HIFI. Results regarding the 557 GHz transition of water are reported here showing that the line is surprisingly broad, and...
Article
Full-text available
OH is an important molecule in the H2O chemistry and the cooling budget of star-forming regions. The goal of the Herschel key program Water in Star-forming regions with Herschel' (WISH) is to study H2O and related species during protostellar evolution. Our aim in this letter is to assess the origin of the OH emission from star-forming regions and...
Article
Molecules containing one (or a few) hydrogen atoms and one heavier atom (hydrides) are predicted to trace ionizing FUV radiation. In some chemical models, FUV emission by the central object or protostar of a star forming region greatly enhances the abundance of some hydrides. Two massive regions, W3 IRS5 and AFGL 2591, have been observed in hydride...
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Embedded protostars interact with their natal cloud through shocks and irradiation. The ambient interstellar medium warms up, allowing icy grain mantles to evaporate and making different chemical routes in the gas phase available. Water then becomes one of the most abundant molecular species in the gas phase. The Herschel key program Water in Star...
Article
The strong feedback processes of massive stars influence the surrounding ISM both locally and on large scales. An important question to be answered is the one of cooling and heating in massive star forming regions. There, heating is provided mostly by far-UV (FUV) and infra-red radiation. Cooling is mostly provided by emission in the fine structure...