Nomura, H., Aikawa, Y., Nakagawa, Y., Millar, T. J.
We have studied the dependence of the profiles of molecular abundances and line emission on the accretion flow in the hot ($\ga 100$K) inner region of protoplanetary disks. The gas-phase reactions...
Cyanopolyynes and sulphur bearing species in hot cores: Chemical and line excitation models (2008)
Chapman, J. F., Wardle, M., Millar, T. J., Burton, M. G., Walsh, A. J.
We present results from a time dependent gas phase chemical model of a hot core based on the physical conditions of G305.2+0.2. While the cyanopolyyne HC_3N has been observed in hot cores, the longer...
Galactic Edge Clouds I: Molecular Line Observations and Chemical Modelling of Edge Cloud 2 (2007)
Ruffle, P. M. E., Millar, T. J., Roberts, H., Lubowich, D. A., Henkel, C., Pasachoff, J. M., ...
Edge Cloud 2 (EC2) is a molecular cloud, about 35 pc in size, with one of the largest galactocentric distances known to exist in the Milky Way. We present observations of a peak CO emission region in...
ATCA 1.2 cm Observations of the Massive Star Forming Region G305.2+0.2 (2007)
Walsh, Andrew J., Chapman, Jacqueline F., Burton, Michael G., Wardle, Mark, Millar, T. J.
We report on Australia Telescope observations of the massive star forming region G305.2+0.2 at 1.2 cm. We detected emission in five molecules towards G305A, confirming its hot core nature. We...
Hydrocarbon anions in interstellar clouds and circumstellar envelopes (2007)
Millar, T. J., Walsh, C., Cordiner, M. A., Chuimín, R. Ní, Herbst, Eric
The recent detection of the hydrocarbon anion C6H- in the interstellar medium has led us to investigate the synthesis of hydrocarbon anions in a variety of interstellar and circumstellar...
Nomura, H., Aikawa, Y., Tsujimoto, M., Nakagawa, Y., Millar, T. J.
Detailed models for the density and temperature profiles of gas and dust in protoplanetary disks are constructed by taking into account X-ray and ultraviolet (UV) irradiation from a central T Tauri...
The James Clerk Maxwell Telescope Spectral Legacy Survey (2007)
Plume, Rene, Fuller, G. A., Helmich, F., Bowey, J., ...
Stars form in the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes that can reveal the dynamics, physics, chemistry, and evolution of these regions, but...
INTERSTELLAR CHEMICAL MODELS WITH MOLECULAR ANIONS (2007)
Herbst, E., Millar, T. J., Cordiner, Martin, Walsh, Catherine, Chuimin, Roisin Ni
Author Institution: Departments of Physics, Astronomy \& Chemistry, The Ohio State University, Columbus, OH 43210; Queen's University Belfast, Belfast, Northern Ireland, UK; Astrophysics Group, The...
Thompson, M. A., Hatchell, J., Walsh, A. J., Macdonald, G. H., Millar, T. J.
We present a SCUBA submillimetre (450 & 850 micron) survey of the environment of 105 IRAS point sources, selected from the Wood & Churchwell (1989a) and Kurtz, Churchwell & Wood (1994) radio...
Kim, S. J., Kim, H. D., Lee, Y., Minh, Y. C., Balasubramanyam, R., Burton, M. G., ...
We have carried out observations toward the W3 complex and G34.3+0.15 using the TRAO 14 m radio telescope to examine in detail the chemical variations occurring while molecular clouds evolve from the...
Kim, S. J., Kim, H. D., Lee, Y., Minh, Y. C., Balasubramanyam, R., Burton, M. G., ...
We have carried out observations toward the W3 complex and G34.3+0.15 using the TRAO 14 m radio telescope to examine in detail the chemical variations occurring while molecular clouds evolve from the...
ASTROCHEMISTRY WITH THE UMIST DATABASE 2005 (2006)
Woodall, J., Agúndez, M., Markwick-Kemper, A. J., Millar, T. J.
Author Institution: Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Sackville Street Building, Manchester M60 1QD, UK; Dpto. Astrofisica Molecular e...
Kim, S. J., Kim, H. D., Lee, Y., Minh, Y. C., Balasubramanyam, R., Burton, M. G., ...
We have carried out observations toward the W3 complex and G34.3+0.15 using the TRAO 14 m radio telescope to examine in detail the chemical variations occurring while molecular clouds evolve from the...
Molecular Hydrogen Emission from Protoplanetary Disks (2005)
We have modeled self-consistently the density and temperature profiles of gas and dust in protoplanetary disks, taking into account irradiation from a central star. Making use of this physical...
Deuterium nucleosynthesis in AGN : Is D cosmological? (2005)
Lubowich, D. A., Kuno, N., Roberts, H., Millar, T. J., Henkel, C., Pasachoff, J., ...
Molecules in bipolar proto-planetary nebulae (2004)
Woods, Paul M., Schoeier, F. L., Zijlstra, A. A., Millar, T. J., Olofsson, H.
Two bipolar proto-planetary nebulae, IRAS16594-4656 and IRAS17150-3224, have been detected in various molecular lines, namely CO, ^{13}CO, HCN and CN, and remain undetected in several other species....
Observational tests for grain chemistry: posterior isotopic labelling (2004)
Charnley, S.B., Ehrenfreund, P., Millar, T.J., Boogert, A.C.A., Markwick, A.J., Butner, H.M., ...
We propose a series of detailed observations that should allow current ideas concerning the important catalytic pathways to interstellar molecules on interstellar dust grains to be tested. The atoms...
THE EFFECT OF CO DEPLETION ON THE $D_{2}CO/H_{2}CO$ RATIO IN PRESTELLAR CORES (2004)
Roberts, H., Herbst, E., Millar, T. J.
Author Institution: Department of Physics, The Ohio State University; Departments of Physics, Astronomy \& Chemistry, The Ohio State University; Department of Physics, UMIST
Transport processes and chemical evolution in steady accretion disk flows (2004)
Ilgner, M., Henning, Th., Markwick, A. J., Millar, T. J.
We study the influence of mass transport processes on the chemical evolution in a protoplanetary accretion disk. Local transport processes by advection as well as global transport processes by...
The Physical and Chemical Structure of Hot Molecular Cores (2003)
We have made self-consistent models of the density and temperature profiles of the gas and dust surrounding embedded luminous objects using a detailed radiative transfer model together with...
Helen Roberts, Eric Herbst, T. J. Millar
In this Letter, we present the first results from updated models of interstellar deuterium chemistry that now include all possible deuterated isotopomers of . We find that in regions of high density...
Aa 402, 189--199 (2003) (2003)
P. M. Woods, T. J. Millar, E. Herbst
We describe the chemistry occurring in a dense slab of outwardly expanding gas in the post-AGB phase of stellar evolution. Despite the high flux of UV photons from the central star, the intrinsic...
Two-Dimensional Models of Protoplanetary Disk Chemistry (2003)
T. J. Millar, H. Nomura, A. J. Markwick
We have developed a two-dimensional model of a ared protoplanetary disk (PPD) incorporating a self-consistent treatment of gas and dust temperature, and a detailed treatment of the gas-phase...
Mon. Not. R. Astron. Soc. 339, 1041--1047 (2003) (2003)
The circumstellar envelopes of very evolved, late-type asymptotic giant branch stars exhibit complex molecular structure. The most striking of these objects is the carbon star IRC (CW Leo), where...
Aa 399, 553--565 (2003) (2003)
This paper reports the results of models of dark cloud chemistry incorporating a depth dependent density distribution with di#usive mixing and adsorption onto grains. The model is based on the...
Sun and protosolar nebula - Working group report (2003)
Kallenbach, R., Robert, F., Geiss, J., Herbst, E., Lammer, H., Marty, B., ...
Deuterium Fractionation in Interstellar Clouds (2002)
This paper reviews the chemical processes responsible for fractionating deuterium in interstellar molecules. We show that this process is intrinsically a low temperature phenomenon and discuss how...
The synthesis of benzene in the protoplanetary nebula CRL618 (2002)
Paul M. Woods, T. J. Millar, A. A. Zijlstra, Eric Herbst
We show that the physical conditions in CRL618 are such that ecient formation of benzene, C 6 H 6 , occurs. A combination of high temperatures, high densities and high ionization rates drives an...
Aa 381, 1026--1038 (2002) (2002)
H. Roberts, G. A. Fuller, T. J. Millar, J. Hatchell, J. V. Buckle
We present observations of [HDCO]/[H2CO] and [DCN]/[HCN] ratios towards a selection of low-mass protostellar cores in three di#erent star forming regions. The best fit to the observed [HDCO]/[H2CO]...
A survey of [HDCO]/[H2CO] and [DCN]/[HCN] ratios towards low- mass protostellar cores (2002)
Roberts, H., Fuller, G. A., Millar, T. J., Hatchell, J., Buckle, J. V.
We present observations of [HDCO]/[H2CO] and [DCN]/[HCN] ratios towards a selection of low-mass protostellar cores in three different star forming regions. The best fit to the observed [HDCO]/[H2CO]...
Molecular D/H ratios in the dense gas surrounding low-mass protostars (2002)
Roberts, H., Fuller, G. A., Millar, T. J., Hatchell, J., Buckle, J. V.
Observations of [HDCO]/[H2CO] and [DCN]/[HCN] ratios have been made towards a selection of low-mass protostellar cores in three different star forming regions. Most [HDCO]/ [H2CO] ratios are between...
Molecular Distributions in the Inner Regions of Protostellar Disks (2002)
Markwick, A. J., Ilgner, M., Millar, T. J., Henning, Th.
The distributions of molecules in the inner regions of a protostellar disk are presented. These were calculated using an uncoupled chemical/dynamical model, with a numerical integration of the...
A sub-mm imaging survey of ultracompact HII regions (2001)
Thompson, M. A., Hatchell, J., Macdonald, G. H., Millar, T. J.
We present the preliminary results of a sub-mm imaging survey of ultracompact HII regions, conducted with the SCUBA bolometer array on JCMT.
H. Roberts, G. A. Fuller, T. J. Millar, J. Hatchell, J. V. Buckle
We present observations of [HDCO]/[H2CO] and [DCN]/[HCN] ratios towards a selection of low-mass protostellar cores in three dierent star forming regions. The best t to the observed [HDCO]/[H2CO]...
Sulphur-Bearing Carbon Chains in (2001)
T. J. Millar, J. R. Flores, A. J. Markwick
We have updated the chemical model of IRC110216 developed by Millar, Herbst & Bettens to include recent routes to the formation of sulphuretted hydrocarbons. The routes are based on a quantum...
DCCH along the TMC-1 ridge (2001)
In this paper we present measurements of the CH2DCCH=CH3CCH ratio along the TMC-1 ridge. The level of deuterium fractionation in this molecule is found to be larger than previously thought, but more...
The UMIST database for astrochemistry 1999 (2001)
We report a new version of the UMIST database for astrochemistry. The previous (1995) version has been updated and its format has been revised. The database contains the rate coe#cients, temperature...
Gas-phase models for the evolved planetary nebulae NGC 6781, M4-9 and NGC 7293 (2001)
A. Ali, O. M. Shalabiea, T. J. Millar
We have studied the chemistry of the molecular gas in evolved planetary nebulae. Three pseudo-time-dependent gas-phase models have been constructed for dense 10 4 --10 5 cm 23 and cool T , 15 K...
SiO in G34.26: out ows and shocks in a high mass star forming region (2001)
J. Hatchell, G. A. Fuller, T. J. Millar
We have looked for SiO emission as evidence of shocks in the high mass star formation region G34.26+0.15. JCMT, VLA and FCRAO observations show that SiO emission is widespread across the region. The...
Astronomy And Astrophysics (2001)
K. Willacy, H. H. Klahr, T. J. Millar
The chemistry in a protoplanetary accretion disk is modelled between a radius of 100 and 0.1 AU of the central object. We find that interaction of the gas with the dust grains is very important, both...
Astronomy And Astrophysics (2001)
We present the first results from a time-dependent chemical model to include a gas-phase reaction scheme for producing doubly-deuterated species. Under normal conditions the formation of these...
Astronomy And Astrophysics (2000)
We have developed new models of the chemistry of deuterium for investigating fractionation in interstellar molecular clouds. We have incorporated the latest information on reactions which affect...
We present an analysis of the data from our Swedish-ESO Submillimetre Telescope molecular line survey in the 1.3 mm band of the N, M, and NW positions in the Sgr B2 molecular cloud. The line...
ISO-SWS Observations of CO2 and H2O in R Cassiopeiae (2000)
We present ISO--SWS spectra of the O-rich Mira variable R Cas, showing CO 2 in absorption and emission, and H 2 O in absorption. The CO 2 absorption feature is the 01 1 0-00 0 0 ro-vibrational band...
Interstellar and Circumstellar Chemistry: The UMIST Database (2000)
Molecules have been detected in interstellar and circumstellar clouds for over 60 years, but it has been only in the past 20 years or so that a signicant eort has gone into chemical kinetic modelling...
Astronomy And Astrophysics (2000)
A. Nilsson, A. Hjalmarson, P. Bergman, T. J. Millar
We here analyse the observational SO and CS data presented in Nilsson et al. (2000). The SO/CS integrated intensity ratio maps are presented for 19 molecular clouds, together with tables of relevant...
Astronomy And Astrophysics (2000)
J. Hatchell, G. A. Fuller, T. J. Millar, M. A. Thompson, G. H. Macdonald
We present 450 and 850m images of five ultracompact Hii regions (G10.47, G12.21, G13.87, G31.41 and G43.89) taken at 9 ## /15 ## resolution with SCUBA on the JCMT, and photometric measurements of the...
On The Abundance Gradients Of Organic Molecules Along The Tmc-1 Ridge A. J. (2000)
A. J. Markwick, T. J. Millar, S. B. Charnley
Gradients in molecular abundances along the TMC-1 ridge have been observed by several authors, most recently in a comprehensive study by Pratap et al. These can be explained by there being a...
Large molecules in the envelope surrounding IRC+10216 (2000)
A new chemical model of the circumstellar envelope surrounding the carbonrich star IRC+10216 has been developed that includes carbon-containing molecules with up to 23 carbon atoms. The model...
T. J. Millar, H. Roberts, A. J. Markwick, S. B. Charnley
this article, we describe the chemistry of H 2 D + and discuss how variations in temperature and elemental abundances aect the level of fractionation in H 2 D + and other species. We describe how...
The Evolution Of Solar Systems (2000)
The recent detection of extra-solar planets and the increasing ability of modern instruments to image disks around young stars has brought a renewed interest in the formation of solar systems. In...
Molecules in High-Mass Star-Forming Regions - Theory and Observation (2000)
It has become clear in recent years that regions of massive star-formation contain small clumps of hot, dense gas. These so-called hot molecular cores are known to be strong emitters of rotational...
Molecular Data Needs in Astrochemistry (2000)
T. J. Millar, M. Walmsley, C. Rebrion-rowe, S. Saito, F. Rostas
The development of astrochemistry is inextricably linked to the generation of fundamental data. In this report, we discuss data needs in terms of astrochemical models, gas-phase kinetics, molecular...
Limits on HDS/H2S abundance ratios in hot molecular cores (1999)
J. Hatchell, H. Roberts, T. J. Millar
We have searched for HDS emission in a small number of hot cores. Using observations of H 34 2 S, we have derived upper limits to the [HDS]/[H 2 S] abundance ratio. The upper limits, which are close...
The Chemistry of Phosphorus in Hot Molecular Cores (1999)
Hot molecular cores in star-forming regions are known to have gas-phase chemical compositions determined by the material evaporated from the icy mantles of interstellar grains, followed by subsequent...
Molecular abundances in the Magellanic Clouds (1999)
C. Henkel, T. J. Millar, J. B. Whiteoak
Detections of CO, CS, SO, C 2 H, HCO + , HCN, HNC, H 2 CO, and C 3 H 2 are reported from LIRS 36, a starforming region in the Small Magellanic Cloud. C 18 O, NO, CH 3 OH, and most notably CN have not...
The DCN/HCN abundance ratio in hot molecular cores (1999)
J. Hatchell, T. J. Millar, S. D. Rodgers
We have observed the 3-2 transitions of DCN and HC 15 N in a number of hot molecular cores previously surveyed by us with the interesting result that the DCN/HCN ratio is low, a few times 10 Gamma3 ,...
Sulphur Chemistry and Evolution in Hot Cores (1999)
J. Hatchell, M. A. Thompson, T. J. Millar, G. H. Macdonald
We compare the results of our JCMT spectral line survey of molecular gas towards ultracompact Hii regions with the predictions of models of sulphur chemistry in hot cores. We investigate the range of...
The Chemistry Of Complex Molecules In Interstellar Clouds (1999)
T J Millar, E Roueff, S B Charnley, S D Rodgers
This paper is concerned with the chemical evolution of large molecules in interstellar clouds. We consider the chemistry and ionisation balance of large PAH-type molecules in diffuse clouds and show...
Important Atomic and Molecular Processes in Galactic Chemistry (1999)
We discuss a variety of processes important in determining the chemical composition within interstellar and circumstellar clouds. Much of the gas-phase chemistry has been well-studied in the...
The UMIST Database for Astrochemistry 1995 (1999)
We report the release of a new version of the UMIST database for astrochemistry. The database contains the rate coefficients of 3864 gas-phase reactions important in interstellar and circumstellar...
Models Of Hot Molecular Cores (1999)
We review the properties of hot molecular cores with specific reference to chemical modelling. While most theoretical modelling has been generic, we discuss models for two specific sources,...
Molecular abundances in the Magellanic Clouds (1999)
C. Henkel, J. B. Whiteoak, T. J. Millar, M. R. Hunt, C. Lemme
Nine H ii regions of the LMC were mapped in 13 CO(1--0) and three in 12 CO(1--0) to study the physical properties of the interstellar medium in the Magellanic Clouds. For N113 the molecular core is...
A search for interstellar gas--phase CO (1999)
F. P. Helmich, J. H. Black, P. Ehrenfreund, P. A. Gerakines, J. H. Lacy, ...
We present searches for gas--phase CO 2 features in the ISO--SWS infrared spectra of four deeply embedded massive young stars, which all show strong solid CO 2 absorption. The abundance of gas--phase...
A 330 -- 360 GHz spectral survey of G34.3+0.15 (1999)
T. J. Millar, G. H. Macdonald, A. G. Gibb
We describe a detailed depth- and timedependent model of the molecular cloud associated with the ultracompact H ii region G34.3+0.15. Previous work on observations of NH 3 and CS indicates that the...
Molecular abundances in the Magellanic Clouds (1999)
C. Henkel, T. J. Millar, J. B. Whiteoak
The first definite discoveries of extragalactic deuterium are reported. DCO + has been detected in three and DCN has been measured in one star-forming region of the Large Magellanic Cloud (LMC)....
Molecular Synthesis in the External Envelopes of AGB Stars (1999)
Introduction Observations of molecules in the circumstellar envelopes (CSEs) of late-type asymptotic giant branch (AGB) stars provide a natural laboratory in which to apply and test astrochemical...
A 330--360 GHz spectral survey of G34.3+0.15 (1999)
G. H. Macdonald, A. G. Gibb, R. J. Habing, T. J. Millar
A 330--360 GHz spectral survey of the hot molecular core associated with the `cometary' ultracompact HII region G34.3+0.15 observed with the James Clerk Maxwell Telescope has detected 338 spectral...
A Survey of Molecular Line Emission Towards Ultracompact (1999)
J. Hatchell, M. A. Thompson, T. J. Millar, G. H. Macdonald
We have used the JCMT to survey molecular line emission towards 14 ultracompact Hii regions (G5.89, G9.62, G10.30, G10.47, G12.21, G13.87, G29.96, G31.41, G34.26, G43.89, G45.12, G45.45, G45.47, and...
Chemistry in Oxygen--Rich Circumstellar Envelopes (1999)
We have considered the chemistry occuring in the circumstellar envelope surrounding an oxygen--rich AGB star and have specifically modelled 4 sources; R Dor, TX Cam, OH231.8+4.2 and IK Tau. Methane...
Molecular abundances in the Magellanic Clouds III. LIRS 36, a star-forming region in the SMC (1997)
Henkel, C., Millar, T. J., Whiteoak, J. B., Marx-Zimmer, M.
Detections of CO, CS, SO, C2H, HCO+, HCN, HNC, H2CO, and C3H2 reported from LIRS 36, a star-forming region in the Small Magellanic Cloud. C18O, NO, CH3OH, and most notably CN have not been detected,...
Molecular abundances in the Magellanic Clouds II. Deuterated species in the LMC (1996)
Henkel, C., Millar, T. J., Whiteoak, J. B., Mauersberger, R.
The first definite discoveries of extragalactic deuterium are reported. DCO$^+$ has been detected in three and DCN has been measured in one star-forming region of the Large Magellanic Cloud (LMC)....
Molecular abundances in the Magellanic Clouds I. A multiline study of five cloud cores (1996)
Henkel, C., Whiteoak, J. B., Millar, T. J., Hunt, M. R., Lemme, C.
Nine HII regions of the LMC were mapped in 13CO(1--0) and three in 12CO(1--0) to study the physical properties of the interstellar medium in the Magellanic Clouds. For N113 the molecular core is...