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Geronimo L Villanueva - One of the best experts on this subject based on the ideXlab platform.
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a survey of volatile species in oort cloud comets c 2001 q4 neat and c 2002 t7 linear at millimeter wavelengths
Astronomy and Astrophysics, 2013Co-Authors: M De Valborro, M Kuppers, P Hartogh, Ladislav Rezac, N Biver, Dominique Bockeleemorvan, J Crovisier, C Jarchow, Geronimo L VillanuevaAbstract:Context. The chemical composition of comets can be inferred using spectroscopic observations in submillimeter and radio wavelengths. Aims. We aim to compare the production rates ratio of several volatiles in two comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), which are generally regarded as dynamically new and likely to originate in the Oort cloud. This type of comets is considered to be composed of primitive material that has not undergone considerable thermal processing. Methods. The line emission in the coma was measured in the comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7‐11 May 2004, at heliocentric distances of 1.0 and 0.7 AU, respectively, by means of highresolution spectroscopy using the 10-m Submillimeter Telescope at the Arizona Radio Observatory. Both objects became very bright and reached naked-eye visibility during their perihelion passage in the spring of 2004. Results. We present a search for six parent- and product-volatile species (HCN, H 2 CO, CO, CS, CH 3 OH, and HNC) in both comets. Multiline observations of the CH 3 OH J = 5‐4 series allow us to estimate the rotational temperature using the rotation diagram technique. We derive rotational temperatures of 54(9) K for C/2001 Q4 (NEAT) and 119(34) K for C/2002 T7 (LINEAR). The gas production rates are computed using the level distribution obtained with a spherically symmetric Molecular Excitation code that includes collisions between neutrals and electrons. The e ects of radiative pumping of the fundamental vibrational levels by infrared photons from the Sun are considered for the case of HCN. We find an HCN production rate of 2:96(5) 10 26 molec. s 1 for comet C/2001 Q4 (NEAT), corresponding to a mixing ratio with respect to H2O of 1:12(2) 10 3 . The mean HCN production rate during the observing period is 4:54(10) 10 26 molec. s 1 for comet C/2002 T7 (LINEAR), which gives a mixing ratio of 1:51(3) 10 3 . Relative abundances of CO, CH3OH, H2CO, CS, and HNC with respect to HCN are 3:05(83) 10 1 , 1:50(25) 10 1 , 1:16(27), 7:02(30) 10 1 , and 5:75(73) 10 2 in comet C/2001 Q4 (NEAT) and < 4:12 10 1 , 4:07(44) 10 1 , 4:72(73), 1:32(6), and 1:09(8) 10 1 in comet C/2002 T7 (LINEAR). Conclusions. With systematically lower mixing ratios in comet C/2001 Q4 (NEAT), production rate ratios of the observed species with respect to H2O lie within the typical ranges of dynamically new comets in both objects. We find a relatively low abundance of CO in C/2001 Q4 (NEAT) compared to the observed range in other comets based on millimeter/submillimeter observations, and a significant upper limit on the CO production in C/2002 T7 (LINEAR) is derived. Depletion of CO suggests partial evaporation from the surface layers during previous visits to the outer Solar System and agrees with previous measurements of dynamically new comets. Rotational temperatures derived from CH3OH rotational diagrams in both C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) are roughly consistent with observations of other comets at similar distances from the Sun.
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a survey of volatile species in oort cloud comets c 2001 q4 neat and c 2002 t7 linear at millimeter wavelengths
arXiv: Earth and Planetary Astrophysics, 2013Co-Authors: M De Valborro, M Kuppers, P Hartogh, Ladislav Rezac, N Biver, Dominique Bockeleemorvan, J Crovisier, C Jarchow, Geronimo L VillanuevaAbstract:The line emission in the coma was measured in the comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7-11 May 2004, at heliocentric distances of 1.0 and 0.7 AU, respectively, by means of high-resolution spectroscopy using the 10-m Submillimeter Telescope (SMT). We present a search for six parent- and product-volatile species (HCN, H2CO, CO, CS, CH3OH, and HNC) in both comets. Multiline observations of the CH3OH J = 5-4 series allow us to estimate the rotational temperature using the rotation diagram technique. We derive rotational temperatures of 54(9) K for C/2001 Q4 (NEAT) and 119(34) K for C/2002 T7 (LINEAR) that are roughly consistent with observations of other comets at similar distances from the Sun. The gas production rates of material are computed using a spherically symmetric Molecular Excitation code that includes collisions between neutrals and electrons. We find an HCN production rate of 2.96(5)e26 molec.s-1 for comet C/2001 Q4 (NEAT), corresponding to a mixing ratio with respect to H2O of 1.12(2)e-3. The mean HCN production rate during the observing period is 4.54(10)e26 molec.s-1 for comet C/2002 T7 (LINEAR), which gives a Q_HCN/Q_H2O mixing ratio of 1.51(3)e-3. With systematically lower mixing ratios in comet C/2001 Q4 (NEAT), production rate ratios of the observed species with respect to H2O lie within the typical ranges of dynamically new comets in both objects. We find a relative low abundance of CO in C/2001 Q4 (NEAT) compared to the observed range in other comets based on millimeter/submillimeter observations, and a significant upper limit on the CO production in C/2002 T7 (LINEAR) is derived. Depletion of CO suggests partial evaporation from the surface layers during previous visits to the outer Solar System and agrees with previous measurements of dynamically new comets.
Prasanta Gorai - One of the best experts on this subject based on the ideXlab platform.
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identification of methyl isocyanate and other complex organic molecules in a hot Molecular core g31 41 0 31
The Astrophysical Journal, 2021Co-Authors: Prasanta Gorai, Ankan Das, Takashi Shimonishi, Dipen Sahu, Suman Kumar Mondal, Bratati Bhat, Sandip K ChakrabartiAbstract:G31.41+0.31 is a well known chemically rich hot Molecular core (HMC). Using Band 3 observations from the Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, toward the source. In addition to this, we have reported the presence of complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, (HCO+)-C-13, and SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming Molecular Excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained Molecular column densities between the existing observational results around other HMCs, it seems that the COMs are favorably produced in the hot core environment (similar to 100 K or higher). Though the spectral emissions toward G31.41+0.31 are not fully resolved, we find that CH3NCO and other COMs are possibly formed on grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03.
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identification of methyl isocyanate and other complex organic molecules in a hot Molecular core g31 41 0 31
arXiv: Astrophysics of Galaxies, 2020Co-Authors: Prasanta Gorai, Ankan Das, Takashi Shimonishi, Dipen Sahu, Suman Kumar Mondal, Bratati Bhat, Sandip K ChakrabartiAbstract:G31.41+0.31 is a well known chemically rich hot Molecular core (HMC). Using Band 3 observations of Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, towards the source. In addition to this, we have reported complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, HCO+, SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming Molecular Excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained Molecular column densities between the existing observational results toward other HMCs, it seems that the COMs are favourably produced in the hot-core environment ($\sim 100$ K or higher). Though the spectral emissions towards G31.41+0.31 are not fully resolved, we find that CH$_3$NCO and other COMs are possibly formed on the grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03, etc.
Sandip K Chakrabarti - One of the best experts on this subject based on the ideXlab platform.
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identification of methyl isocyanate and other complex organic molecules in a hot Molecular core g31 41 0 31
The Astrophysical Journal, 2021Co-Authors: Prasanta Gorai, Ankan Das, Takashi Shimonishi, Dipen Sahu, Suman Kumar Mondal, Bratati Bhat, Sandip K ChakrabartiAbstract:G31.41+0.31 is a well known chemically rich hot Molecular core (HMC). Using Band 3 observations from the Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, toward the source. In addition to this, we have reported the presence of complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, (HCO+)-C-13, and SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming Molecular Excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained Molecular column densities between the existing observational results around other HMCs, it seems that the COMs are favorably produced in the hot core environment (similar to 100 K or higher). Though the spectral emissions toward G31.41+0.31 are not fully resolved, we find that CH3NCO and other COMs are possibly formed on grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03.
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identification of methyl isocyanate and other complex organic molecules in a hot Molecular core g31 41 0 31
arXiv: Astrophysics of Galaxies, 2020Co-Authors: Prasanta Gorai, Ankan Das, Takashi Shimonishi, Dipen Sahu, Suman Kumar Mondal, Bratati Bhat, Sandip K ChakrabartiAbstract:G31.41+0.31 is a well known chemically rich hot Molecular core (HMC). Using Band 3 observations of Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, towards the source. In addition to this, we have reported complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, HCO+, SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming Molecular Excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained Molecular column densities between the existing observational results toward other HMCs, it seems that the COMs are favourably produced in the hot-core environment ($\sim 100$ K or higher). Though the spectral emissions towards G31.41+0.31 are not fully resolved, we find that CH$_3$NCO and other COMs are possibly formed on the grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03, etc.
M De Valborro - One of the best experts on this subject based on the ideXlab platform.
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a survey of volatile species in oort cloud comets c 2001 q4 neat and c 2002 t7 linear at millimeter wavelengths
Astronomy and Astrophysics, 2013Co-Authors: M De Valborro, M Kuppers, P Hartogh, Ladislav Rezac, N Biver, Dominique Bockeleemorvan, J Crovisier, C Jarchow, Geronimo L VillanuevaAbstract:Context. The chemical composition of comets can be inferred using spectroscopic observations in submillimeter and radio wavelengths. Aims. We aim to compare the production rates ratio of several volatiles in two comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), which are generally regarded as dynamically new and likely to originate in the Oort cloud. This type of comets is considered to be composed of primitive material that has not undergone considerable thermal processing. Methods. The line emission in the coma was measured in the comets, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7‐11 May 2004, at heliocentric distances of 1.0 and 0.7 AU, respectively, by means of highresolution spectroscopy using the 10-m Submillimeter Telescope at the Arizona Radio Observatory. Both objects became very bright and reached naked-eye visibility during their perihelion passage in the spring of 2004. Results. We present a search for six parent- and product-volatile species (HCN, H 2 CO, CO, CS, CH 3 OH, and HNC) in both comets. Multiline observations of the CH 3 OH J = 5‐4 series allow us to estimate the rotational temperature using the rotation diagram technique. We derive rotational temperatures of 54(9) K for C/2001 Q4 (NEAT) and 119(34) K for C/2002 T7 (LINEAR). The gas production rates are computed using the level distribution obtained with a spherically symmetric Molecular Excitation code that includes collisions between neutrals and electrons. The e ects of radiative pumping of the fundamental vibrational levels by infrared photons from the Sun are considered for the case of HCN. We find an HCN production rate of 2:96(5) 10 26 molec. s 1 for comet C/2001 Q4 (NEAT), corresponding to a mixing ratio with respect to H2O of 1:12(2) 10 3 . The mean HCN production rate during the observing period is 4:54(10) 10 26 molec. s 1 for comet C/2002 T7 (LINEAR), which gives a mixing ratio of 1:51(3) 10 3 . Relative abundances of CO, CH3OH, H2CO, CS, and HNC with respect to HCN are 3:05(83) 10 1 , 1:50(25) 10 1 , 1:16(27), 7:02(30) 10 1 , and 5:75(73) 10 2 in comet C/2001 Q4 (NEAT) and < 4:12 10 1 , 4:07(44) 10 1 , 4:72(73), 1:32(6), and 1:09(8) 10 1 in comet C/2002 T7 (LINEAR). Conclusions. With systematically lower mixing ratios in comet C/2001 Q4 (NEAT), production rate ratios of the observed species with respect to H2O lie within the typical ranges of dynamically new comets in both objects. We find a relatively low abundance of CO in C/2001 Q4 (NEAT) compared to the observed range in other comets based on millimeter/submillimeter observations, and a significant upper limit on the CO production in C/2002 T7 (LINEAR) is derived. Depletion of CO suggests partial evaporation from the surface layers during previous visits to the outer Solar System and agrees with previous measurements of dynamically new comets. Rotational temperatures derived from CH3OH rotational diagrams in both C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) are roughly consistent with observations of other comets at similar distances from the Sun.
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a survey of volatile species in oort cloud comets c 2001 q4 neat and c 2002 t7 linear at millimeter wavelengths
arXiv: Earth and Planetary Astrophysics, 2013Co-Authors: M De Valborro, M Kuppers, P Hartogh, Ladislav Rezac, N Biver, Dominique Bockeleemorvan, J Crovisier, C Jarchow, Geronimo L VillanuevaAbstract:The line emission in the coma was measured in the comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR), that were observed on five consecutive nights, 7-11 May 2004, at heliocentric distances of 1.0 and 0.7 AU, respectively, by means of high-resolution spectroscopy using the 10-m Submillimeter Telescope (SMT). We present a search for six parent- and product-volatile species (HCN, H2CO, CO, CS, CH3OH, and HNC) in both comets. Multiline observations of the CH3OH J = 5-4 series allow us to estimate the rotational temperature using the rotation diagram technique. We derive rotational temperatures of 54(9) K for C/2001 Q4 (NEAT) and 119(34) K for C/2002 T7 (LINEAR) that are roughly consistent with observations of other comets at similar distances from the Sun. The gas production rates of material are computed using a spherically symmetric Molecular Excitation code that includes collisions between neutrals and electrons. We find an HCN production rate of 2.96(5)e26 molec.s-1 for comet C/2001 Q4 (NEAT), corresponding to a mixing ratio with respect to H2O of 1.12(2)e-3. The mean HCN production rate during the observing period is 4.54(10)e26 molec.s-1 for comet C/2002 T7 (LINEAR), which gives a Q_HCN/Q_H2O mixing ratio of 1.51(3)e-3. With systematically lower mixing ratios in comet C/2001 Q4 (NEAT), production rate ratios of the observed species with respect to H2O lie within the typical ranges of dynamically new comets in both objects. We find a relative low abundance of CO in C/2001 Q4 (NEAT) compared to the observed range in other comets based on millimeter/submillimeter observations, and a significant upper limit on the CO production in C/2002 T7 (LINEAR) is derived. Depletion of CO suggests partial evaporation from the surface layers during previous visits to the outer Solar System and agrees with previous measurements of dynamically new comets.
Ankan Das - One of the best experts on this subject based on the ideXlab platform.
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identification of methyl isocyanate and other complex organic molecules in a hot Molecular core g31 41 0 31
The Astrophysical Journal, 2021Co-Authors: Prasanta Gorai, Ankan Das, Takashi Shimonishi, Dipen Sahu, Suman Kumar Mondal, Bratati Bhat, Sandip K ChakrabartiAbstract:G31.41+0.31 is a well known chemically rich hot Molecular core (HMC). Using Band 3 observations from the Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, toward the source. In addition to this, we have reported the presence of complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, (HCO+)-C-13, and SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming Molecular Excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained Molecular column densities between the existing observational results around other HMCs, it seems that the COMs are favorably produced in the hot core environment (similar to 100 K or higher). Though the spectral emissions toward G31.41+0.31 are not fully resolved, we find that CH3NCO and other COMs are possibly formed on grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03.
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identification of methyl isocyanate and other complex organic molecules in a hot Molecular core g31 41 0 31
arXiv: Astrophysics of Galaxies, 2020Co-Authors: Prasanta Gorai, Ankan Das, Takashi Shimonishi, Dipen Sahu, Suman Kumar Mondal, Bratati Bhat, Sandip K ChakrabartiAbstract:G31.41+0.31 is a well known chemically rich hot Molecular core (HMC). Using Band 3 observations of Atacama Large Millimeter Array (ALMA), we have analyzed the chemical and physical properties of the source. We have identified methyl isocyanate (CH3NCO), a precursor of prebiotic molecules, towards the source. In addition to this, we have reported complex organic molecules (COMs) like methanol (CH3OH), methanethiol (CH3SH), and methyl formate (CH3OCHO). Additionally, we have used transitions from molecules like HCN, HCO+, SiO to trace the presence of infall and outflow signatures around the star-forming region. For the COMs, we have estimated the column densities and kinetic temperatures, assuming Molecular Excitation under local thermodynamic equilibrium (LTE) conditions. From the estimated kinetic temperatures of certain COMs, we found that multiple temperature components may be present in the HMC environment. Comparing the obtained Molecular column densities between the existing observational results toward other HMCs, it seems that the COMs are favourably produced in the hot-core environment ($\sim 100$ K or higher). Though the spectral emissions towards G31.41+0.31 are not fully resolved, we find that CH$_3$NCO and other COMs are possibly formed on the grain/ice phase and populate the gas environment similar to other hot cores like Sgr B2, Orion KL, and G10.47+0.03, etc.