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Search Results: 1 - 10 of 310639 matches for " J. Santiago-Garcia "
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A molecular survey of outflow gas: velocity-dependent shock chemistry and the peculiar composition of the EHV gas
M. Tafalla,J. Santiago-Garcia,A. Hacar,R. Bachiller
Physics , 2010, DOI: 10.1051/0004-6361/201015158
Abstract: (Abridged) We present a molecular survey of the outflows powered by L1448-mm and IRAS 04166+2706, two sources with prominent wing and extremely high velocity (EHV) components in their CO spectra. The molecular composition of the two outflows presents systematic changes with velocity that we analyze by dividing the outflow in three chemical regimes, two of them associated with the wing component and the other the EHV gas. The analysis of the two wing regimes shows that species like H2CO and CH3OH favor the low-velocity gas, while SiO and HCN are more abundant in the fastest gas. We also find that the EHV regime is relatively rich in O-bearing species, as is not only detected in CO and SiO (already reported elsewhere), but also in SO, CH3OH, and H2CO (newly reported here), with a tentative detection in HCO+. At the same time, the EHV regime is relatively poor in C-bearing molecules like CS and HCN. We suggest that this difference in composition arises from a lower C/O ratio in the EHV gas. The different chemical compositions of the wing and EHV regimes suggest that these two outflow components have different physical origins. The wing component is better explained by shocked ambient gas, although none of the existing shock models explains all observed features. The peculiar composition of the EHV gas may reflect its origin as a dense wind from the protostar or its surrounding disk.
The extremely collimated bipolar H_2O jet from the NGC 1333-IRAS 4B protostar
J. -F. Desmurs,C. Codella,J. Santiago-Garcia,M. Tafalla,R. Bachiller
Physics , 2009, DOI: 10.1051/0004-6361/200811365
Abstract: We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding medium. The main aim is to measure the absolute positions and proper motions of the H_2O spots in order to investigate the kinematics of the region from where the jet is launched. We imaged the protostars in the nearby region NGC 1333-IRAS 4 in the water maser line at 22.2 GHz by using the VLBA in phase-reference mode at the milliarcsecond scale over four epochs, spaced by one month to measure proper motions. Two protostars (A2 and B) were detected in a highly variable H_2O maser emission, with an active phase shorter than four weeks. The H_2O maps allow us to trace the fast jet driven by the B protostar: we observed both the red- and blue-shifted lobes very close to the protostar, =< 35 AU, moving away with projected velocities of ~10-50 km/s. The comparison with the molecular outflow observed at larger scale suggests a jet precession with a 18'/yr rate. By measuring the positional spread of the H_2O spots we estimate a jet width of ~2 AU at a distance of ~12 AU from the driving protostar.
Origin of the hot gas in low-mass protostars: Herschel-PACS spectroscopy of HH 46
T. A. van Kempen,L. E. Kristensen,G. J. Herczeg,R. Visser,E. F. van Dishoeck,S. F. Wampfler,S. Bruderer,A. O. Benz,S. D. Doty,C. Brinch,M. R. Hogerheijde,J. K. J?rgensen,M. Tafalla,D. Neufeld,R. Bachiller,A. Baudry,M. Benedettini,E. A. Bergin,P. Bjerkeli,G. A. Blake,S. Bontemps,J. Braine,P. Caselli,J. Cernicharo,C. Codella,F. Daniel,A. M. di Giorgio,C. Dominik,P. Encrenaz,M. Fich,A. Fuente,T. Giannini,J. R. Goicoechea,Th. de Graauw,F. Helmich,F. Herpin,T. Jacq,D. Johnstone,M. J. Kaufman,B. Larsson,D. Lis,R. Liseau,M. Marseille,C. McCoey,G. Melnick,B. Nisini,M. Olberg,B. Parise,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,F. van der Tak,F. Wyrowski,U. A. Yildiz,M. Ciechanowicz,L. Dubbeldam,S. Glenz,R. Huisman,R. H. Lin,P. Morris,J. A. Murphy,N. Trappe
Physics , 2010, DOI: 10.1051/0004-6361/201014615
Abstract: 'Water in Star-forming regions with Herschel' (WISH) is a Herschel Key Programme aimed at understanding the physical and chemical structure of young stellar objects (YSOs) with a focus on water and related species. The low-mass protostar HH 46 was observed with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory to measure emission in H2O, CO, OH, [OI], and [CII] lines located between 63 and 186 um. The excitation and spatial distribution of emission can disentangle the different heating mechanisms of YSOs, with better spatial resolution and sensitivity than previously possible. Far-IR line emission is detected at the position of the protostar and along the outflow axis. The OH emission is concentrated at the central position, CO emission is bright at the central position and along the outflow, and H2O emission is concentrated in the outflow. In addition, [OI] emission is seen in low-velocity gas, assumed to be related to the envelope, and is also seen shifted up to 170 km/s in both the red- and blue-shifted jets. Envelope models are constructed based on previous observational constraints. They indicate that passive heating of a spherical envelope by the protostellar luminosity cannot explain the high-excitation molecular gas detected with PACS, including CO lines with upper levels at >2500 K above the ground state. Instead, warm CO and H2O emission is probably produced in the walls of an outflow-carved cavity in the envelope, which are heated by UV photons and non-dissociative C-type shocks. The bright OH and [OI] emission is attributed to J-type shocks in dense gas close to the protostar. In the scenario described here, the combined cooling by far-IR lines within the central spatial pixel is estimated to be 2 \times 10-2 L_sun, with 60-80% attributed to J- and C-type shocks produced by interactions between the jet and the envelope.
Water in massive star-forming regions: HIFI observations of W3 IRS5
L. Chavarria,F. Herpin,T. Jacq,J. Braine,S. Bontemps,A. Baudry,M. Marseille,F. van der Tak,B. Pietropaoli,F. Wyrowski,R. Shipman,W. Frieswijk,E. F. van Dishoeck,J. Cernicharo,R. Bachiller,M. Benedettini,A. O. Benz,E. Bergin,P. Bjerkeli,G. A. Blake,S. Bruderer,P. Caselli,C. Codella,F. Daniel,A. M. di Giorgio,C. Dominik,S. D. Doty,P. Encrenaz,M. Fich,A. Fuente,T. Giannini,J. R. Goicoechea,Th. de Graauw,P. Hartogh,F. Helmich,G. J. Herczeg,M. R. Hogerheijde,D. Johnstone,J. K. J?rgensen,L. E. Kristensen,B. Larsson,D. Lis,R. Liseau,C. McCoey,G. Melnick,B. Nisini,M. Olberg,B. Parise,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,J. Stutzki R. Szczerba,M. Tafalla,A. Tielens,T. A. van Kempen,R. Visser,S. F. Wampfler,J. Willem,U. A. Y?ld?z
Physics , 2010, DOI: 10.1051/0004-6361/201015113
Abstract: We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. The o-H17O 110-101, p-H18O 111-000, p-H2O 22 202-111, p-H2O 111-000, o-H2O 221-212, and o-H2O 212-101 lines, covering a frequency range from 552 up to 1669 GHz, have been detected at high spectral resolution with HIFI. The water lines in W3 IRS5 show well-defined high-velocity wings that indicate a clear contribution by outflows. Moreover, the systematically blue-shifted absorption in the H2O lines suggests expansion, presumably driven by the outflow. No infall signatures are detected. The p-H2O 111-000 and o-H2O 212-101 lines show absorption from the cold material (T ~ 10 K) in which the high-mass protostellar envelope is embedded. One-dimensional radiative transfer models are used to estimate water abundances and to further study the kinematics of the region. We show that the emission in the rare isotopologues comes directly from the inner parts of the envelope (T > 100 K) where water ices in the dust mantles evaporate and the gas-phase abundance increases. The resulting jump in the water abundance (with a constant inner abundance of 10^{-4}) is needed to reproduce the o-H17O 110-101 and p-H18O 111-000 spectra in our models. We estimate water abundances of 10^{-8} to 10^{-9} in the outer parts of the envelope (T < 100 K). The possibility of two protostellar objects contributing to the emission is discussed.
Herschel-HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region
U. A. Y?ld?z,E. F. van Dishoeck,L. E. Kristensen,R. Visser,J. K. J?rgensen,G. J. Herczeg,T. A. van Kempen,M. R. Hogerheijde,S. D. Doty,A. O. Benz,S. Bruderer,S. F. Wampfler,E. Deul,R. Bachiller,A. Baudry,M. Benedettini,E. Bergin,P. Bjerkeli,G. A. Blake,S. Bontemps,J. Braine,P. Caselli,J. Cernicharo,C. Codella,F. Daniel,A. M. di Giorgio,C. Dominik,P. Encrenaz,M. Fich,A. Fuente,T. Giannini,J. R. Goicoechea,Th. de Graauw,F. Helmich,F. Herpin,T. Jacq,D. Johnstone,B. Larsson,D. Lis,R. Liseau,F. -C. Liu,M. Marseille,C. McCoey,G. Melnick,D. Neufeld,B. Nisini,M. Olberg,B. Parise,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,M. Tafalla,A. G. G. M. Tielens,F. van der Tak,F. Wyrowski,P. Dieleman,W. Jellema,V. Ossenkopf,R. Schieder,J. Stutzki
Physics , 2010, DOI: 10.1051/0004-6361/201015119
Abstract: Herschel-HIFI observations of high-J lines (up to J_u=10) of 12CO, 13CO and C18O are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS 4B, obtained as part of the Water In Star-forming regions with Herschel (WISH) key program. The spectrally-resolved HIFI data are complemented by ground-based observations of lower-J CO and isotopologue lines. The 12CO 10-9 profiles are dominated by broad (FWHM 25-30 km s^-1) emission. Radiative transfer models are used to constrain the temperature of this shocked gas to 100-200 K. Several CO and 13CO line profiles also reveal a medium-broad component (FWHM 5-10 km s^-1), seen prominently in H2O lines. Column densities for both components are presented, providing a reference for determining abundances of other molecules in the same gas. The narrow C18O 9-8 lines probe the warmer part of the quiescent envelope. Their intensities require a jump in the CO abundance at an evaporation temperature around 25 K, thus providing new direct evidence for a CO ice evaporation zone around low-mass protostars.
Herschel observations of the hydroxyl radical (OH) in young stellar objects
S. F. Wampfler,G. J. Herczeg,S. Bruderer,A. O. Benz,E. F. van Dishoeck,L. E. Kristensen,R. Visser,S. D. Doty,M. Melchior,T. A. van Kempen,U. A. Yildiz,C. Dedes,J. R. Goicoechea,A. Baudry,G. Melnick,R. Bachiller,M. Benedettini,E. Bergin,P. Bjerkeli,G. A. Blake,S. Bontemps,J. Braine,P. Caselli,J. Cernicharo,C. Codella,F. Daniel,A. M. di Giorgio,C. Dominik,P. Encrenaz,M. Fich,A. Fuente,T. Giannini,Th. de Graauw,F. Helmich,F. Herpin,T. Jacq,D. Johnstone,J. K. J ?rgensen,B. Larsson,D. Lis,R. Liseau,M. Marseille,C. McCoey,D. Neufeld,B. Nisini,M. Olberg,B. Parise,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,M. Tafalla,F. F. S. van der Tak,F. Wyrowski,P. Roelfsema,W. Jellema,P. Dieleman,E. Caux,J. Stutzki
Physics , 2010, DOI: 10.1051/0004-6361/201015112
Abstract: Water in Star-forming regions with Herschel (WISH) is a Herschel Key Program investigating the water chemistry in young stellar objects (YSOs) during protostellar evolution. Hydroxyl (OH) is one of the reactants in the chemical network most closely linked to the formation and destruction of H2O. High-temperature chemistry connects OH and H2O through the OH + H2 <-> H2O + H reactions. Formation of H2O from OH is efficient in the high-temperature regime found in shocks and the innermost part of protostellar envelopes. Moreover, in the presence of UV photons, OH can be produced from the photo-dissociation of H2O. High-resolution spectroscopy of the OH 163.12 micron triplet towards HH 46 and NGC 1333 IRAS 2A was carried out with the Heterodyne Instrument for the Far Infrared (HIFI) on board Herschel. The low- and intermediate-mass YSOs HH 46, TMR 1, IRAS 15398-3359, DK Cha, NGC 7129 FIRS 2, and NGC 1333 IRAS 2A were observed with the Photodetector Array Camera and Spectrometer (PACS) in four transitions of OH and two [OI] lines. The OH transitions at 79, 84, 119, and 163 micron and [OI] emission at 63 and 145 micron were detected with PACS towards the class I low-mass YSOs as well as the intermediate-mass and class I Herbig Ae sources. No OH emission was detected from the class 0 YSO NGC 1333 IRAS 2A, though the 119 micron was detected in absorption. With HIFI, the 163.12 micron was not detected from HH 46 and only tentatively detected from NGC 1333 IRAS 2A. The combination of the PACS and HIFI results for HH 46 constrains the line width (FWHM > 11 km/s) and indicates that the OH emission likely originates from shocked gas. This scenario is supported by trends of the OH flux increasing with the [OI] flux and the bolometric luminosity. Similar OH line ratios for most sources suggest that OH has comparable excitation temperatures despite the different physical properties of the sources.
Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk
E. A. Bergin,M. R. Hogerheijde,C. Brinch,J. Fogel,U. A. Yildiz,L. E. Kristensen,E. F. van~Dishoeck,T. A. Bell,G. A. Blake,J. Cernicharo,C. Dominik,D. Lis,G. Melnick,D. Neufeld,O. Panic,J. C. Pearson,R. Bachiller,A. Baudry,M. Benedettini,A. O. Benz,P. Bjerkeli,S. Bontemps,J. Braine,S. Bruderer,P. Caselli,C. Codella,F. Daniel,A. M. di Giorgio,S. D. Doty,P. Encrenaz,M. Fich,A. Fuente,T. Giannini,J. R. Goicoechea,Th. de Graauw,F. Helmich,G. J. Herczeg,F. Herpin,T. Jacq,D. Johnstone,J. K. Jorgensen,B. Larsson,R. Liseau,M. Marseille,C. McCoey,B. Nisini,M. Olberg,B. Parise,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,M. Tafalla,T. A. van Kempen,R. Visser,S. F. Wampfler,F. Wyrowski,F. van der Tak,W. Jellema,A. G. G. M. Tielens,P. Hartogh,J. Stutzki,R. Szczerba
Physics , 2010, DOI: 10.1051/0004-6361/201015104
Abstract: We performed a sensitive search for the ground-state emission lines of ortho- and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI instrument. No strong lines are detected down to 3sigma levels in 0.5 km/s channels of 4.2 mK for the 1_{10}--1_{01} line and 12.6 mK for the 1_{11}--0_{00} line. We report a very tentative detection, however, of the 1_{10}--1_{01} line in the Wide Band Spectrometer, with a strength of T_{mb}=2.7 mK, a width of 5.6 km/s and an integrated intensity of 16.0 mK km/s. The latter constitutes a 6sigma detection. Regardless of the reality of this tentative detection, model calculations indicate that our sensitive limits on the line strengths preclude efficient desorption of water in the UV illuminated regions of the disk. We hypothesize that more than 95-99% of the water ice is locked up in coagulated grains that have settled to the midplane.
Water vapor toward starless cores: the Herschel view
P. Caselli,E. Keto,L. Pagani,Y. Aikawa,U. A. Yildiz,F. F. S. van der Tak,M. Tafalla,E. A. Bergin,B. Nisini,C. Codella,E. F. van Dishoeck,R. Bachiller,A. Baudry,M. Benedettini,A. O. Benz,P. Bjerkeli,G. A. Blake,S. Bontemps,J. Braine,S. Bruderer,J. Cernicharo,F. Daniel,A. M. di Giorgio,C. Dominik,S. D. Doty,P. Encrenaz,M. Fich,A. Fuente,T. Gaier,T. Giannini,J. R. Goicoechea,Th. de Graauw,F. Helmich,G. J. Herczeg,F. Herpin,M. R. Hogerheijde,B. Jackson,T. Jacq,H. Javadi,D. Johnstone,J. K. Jorgensen,D. Kester,L. E. Kristensen,W. Laauwen,B. Larsson,D. Lis,R. Liseau,W. Luinge,M. Marseille,C. McCoey,A. Megej,G. Melnick,D. Neufeld,M. Olberg,B. Parise,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,P. Siegel,T. A. van Kempen,R. Visser,S. F. Wampfler,F. Wyrowski
Physics , 2010, DOI: 10.1051/0004-6361/201015097
Abstract: SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) < 7x10^-9). We investigate the chemistry of water vapor in starless cores beyond the previous upper limits using the highly improved angular resolution and sensitivity of Herschel and measure the abundance of water vapor during evolutionary stages just preceding star formation. High spectral resolution observations of the fundamental ortho water (o-H2O) transition (557 GHz) were carried out with Herschel HIFI toward two starless cores: B68, a Bok globule, and L1544, a prestellar core embedded in the Taurus molecular cloud complex. The rms in the brightness temperature measured for the B68 and L1544 spectra is 2.0 and 2.2 mK, respectively, in a velocity bin of 0.59 km s^-1. The continuum level is 3.5+/-0.2 mK in B68 and 11.4+/-0.4 mK in L1544. No significant feature is detected in B68 and the 3 sigma upper limit is consistent with a column density of o-H2O N(o-H2O) < 2.5x10^13 cm^-2, or a fractional abundance x(o-H2O) < 1.3x10^-9, more than an order of magnitude lower than the SWAS upper limit on this source. The L1544 spectrum shows an absorption feature at a 5 sigma level from which we obtain the first value of the o-H2O column density ever measured in dark clouds: N(o-H2O) = (8+/-4)x10^12 cm^-2. The corresponding fractional abundance is x(o-H2O) ~ 5x10^-9 at radii > 7000 AU and ~2x10^-10 toward the center. The radiative transfer analysis shows that this is consistent with a x(o-H2O) profile peaking at ~10^-8, 0.1 pc away from the core center, where both freeze-out and photodissociation are negligible. Herschel has provided the first measurement of water vapor in dark regions. Prestellar cores such as L1544 (with their high central densities, strong continuum, and large envelopes) are very promising tools to finally shed light on the solid/vapor balance of water in molecular clouds.
Water in low-mass star-forming regions with Herschel: HIFI spectroscopy of NGC1333
L. E. Kristensen,R. Visser,E. F. van Dishoeck,U. A. Y?ld?z,S. D. Doty,G. J. Herczeg,F. -C. Liu,B. Parise,J. K. J?rgensen,T. A. van Kempen,C. Brinch,S. F. Wampfler,S. Bruderer,A. O. Benz,M. R. Hogerheijde,E. Deul,R. Bachiller,A. Baudry,M. Benedettini,E. A. Bergin,P. Bjerkeli,G. A. Blake,S. Bontemps,J. Braine,P. Caselli,J. Cernicharo,C. Codella,F. Daniel,Th. de Graauw,A. M. di Giorgio,C. Dominik,P. Encrenaz,M. Fich,A. Fuente,T. Giannini,J. R. Goicoechea,F. Helmich,F. Herpin,T. Jacq,D. Johnstone,M. J. Kaufman,B. Larsson,D. Lis,R. Liseau,M. Marseille,C. McCoey,G. Melnick,D. Neufeld,B. Nisini,M. Olberg,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,M. Tafalla,A. G. G. M. Tielens,F. van der Tak,F. Wyrowski,D. Beintema,A. de Jonge,P. Dieleman,V. Ossenkopf,P. Roelfsema,J. Stutzki,N. Whyborn
Physics , 2010, DOI: 10.1051/0004-6361/201015100
Abstract: 'Water In Star-forming regions with Herschel' (WISH) is a key programme dedicated to studying the role of water and related species during the star-formation process and constraining the physical and chemical properties of young stellar objects. The Heterodyne Instrument for the Far-Infrared (HIFI) on the Herschel Space Observatory observed three deeply embedded protostars in the low-mass star-forming region NGC1333 in several H2-16O, H2-18O, and CO transitions. Line profiles are resolved for five H16O transitions in each source, revealing them to be surprisingly complex. The line profiles are decomposed into broad (>20 km/s), medium-broad (~5-10 km/s), and narrow (<5 km/s) components. The H2-18O emission is only detected in broad 1_10-1_01 lines (>20 km/s), indicating that its physical origin is the same as for the broad H2-16O component. In one of the sources, IRAS4A, an inverse P Cygni profile is observed, a clear sign of infall in the envelope. From the line profiles alone, it is clear that the bulk of emission arises from shocks, both on small (<1000 AU) and large scales along the outflow cavity walls (~10 000 AU). The H2O line profiles are compared to CO line profiles to constrain the H2O abundance as a function of velocity within these shocked regions. The H2O/CO abundance ratios are measured to be in the range of ~0.1-1, corresponding to H2O abundances of ~10-5-10-4 with respect to H2. Approximately 5-10% of the gas is hot enough for all oxygen to be driven into water in warm post-shock gas, mostly at high velocities.
Herschel-HIFI detections of hydrides towards AFGL 2591 (Envelope emission versus tenuous cloud absorption)
S. Bruderer,A. O. Benz,E. F. van Dishoeck,M. Melchior,S. D. Doty,F. van der Tak,P. St?uber,S. F. Wampfler,C. Dedes,U. A. Y?ld?z,L. Pagani,T. Giannini,Th. de Graauw,N. Whyborn,D. Teyssier,W. Jellema,R. Shipman,R. Schieder,N. Honingh,E. Caux,W. B?chtold,A. Csillaghy,C. Monstein,R. Bachiller,A. Baudry,M. Benedettini,E. Bergin,P. Bjerkeli,G. A. Blake,S. Bontemps,J. Braine,P. Caselli,J. Cernicharo,C. Codella,F. Daniel,A. M. di Giorgio,C. Dominik,P. Encrenaz,M. Fich,A. Fuente,J. R. Goicoechea,F. Helmich,G. J. Herczeg,F. Herpin,M. R. Hogerheijde,T. Jacq,D. Johnstone,J. K. J?rgensen,L. E. Kristensen,B. Larsson,D. Lis,R. Liseau,M. Marseille,C. McCoey,G. Melnick,D. Neufeld,B. Nisini,M. Olberg,B. Parise,J. C. Pearson,R. Plume,C. Risacher,J. Santiago-Garcia,P. Saraceno,R. Shipman,M. Tafalla,T. A. van Kempen,R. Visser,F. Wyrowski
Physics , 2010, DOI: 10.1051/0004-6361/201015098
Abstract: The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution and in multiple transitions. Here, we report deep integrations using HIFI in different lines of hydrides towards the high-mass star forming region AFGL 2591. Detected are CH, CH+, NH, OH+, H2O+, while NH+ and SH+ have not been detected. All molecules except for CH and CH+ are seen in absorption with low excitation temperatures and at velocities different from the systemic velocity of the protostellar envelope. Surprisingly, the CH(JF,P = 3/2_2,- - 1/2_1,+) and CH+(J = 1 - 0, J = 2 - 1) lines are detected in emission at the systemic velocity. We can assign the absorption features to a foreground cloud and an outflow lobe, while the CH and CH+ emission stems from the envelope. The observed abundance and excitation of CH and CH+ can be explained in the scenario of FUV irradiated outflow walls, where a cavity etched out by the outflow allows protostellar FUV photons to irradiate and heat the envelope at larger distances driving the chemical reactions that produce these molecules.
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