Luminosity outbursts of FU Ori-type objects(FUors)allow us to observe in the gas the molecules that are typically present in the ice in protoplanetary disks.In particular,the fraction of deuterated water,which is usua...Luminosity outbursts of FU Ori-type objects(FUors)allow us to observe in the gas the molecules that are typically present in the ice in protoplanetary disks.In particular,the fraction of deuterated water,which is usually mostly frozen in the midplane of a protoplanetary disk,has been measured for the first time in the gas of the disk around FUor V883 Ori.We test the hypothesis that the observed high HDO/H_(2)O ratio in the V883 Ori protoplanetary disk can be explained by luminosity outbursts of different amplitude,including a series of two consecutive outbursts.Using the ANDES astrochemical code,we modeled the distributions of water and deuterated water abundances under the action of luminosity outbursts of different amplitudes(from 400 to10,000 L_(⊙))and at different stellar luminosities at the pre-outburst stage.We show that the best agreement with the observed HDO/H_(2)O profile is obtained for outburst amplitudes of 2000 and 10,000 L_(⊙),while the observed bolometric luminosity of V883 Ori does not exceed 400 L_(⊙).We discuss possible reasons for this discrepancy,including the presence of past luminosity outbursts,the age of the star,and the influence of additional heating mechanisms in the midplane of the protoplanetary disk.We also consider how the high observed HDO/H_(2)O ratio may be related to the evolution of the chemical composition of the ice in the protoplanetary disk and the chemical processes activated under outburst conditions.展开更多
Non-similarity solutions are obtained for one-dimensional isothermal and adiabatic flow behind strong cylindrical shock wave propagation in a rotational ax-isymmetric dusty gas, which has a variable azimuthal and axia...Non-similarity solutions are obtained for one-dimensional isothermal and adiabatic flow behind strong cylindrical shock wave propagation in a rotational ax-isymmetric dusty gas, which has a variable azimuthal and axial fluid velocity. The dusty gas is assumed to be a mixture of small solid particles and perfect gas. The equi-librium flow conditions are assumed to be maintained, and the density of the mixture is assumed to be varying and obeying an exponential law. The fluid velocities in the ambient medium are assumed to obey exponential laws. The shock wave moves with variable velocity. The effects of variation of the mass concentration of solid particles in the mixture, and the ratio of the density of solid particles to the initial density of the gas on the flow variables in the region behind the shock are investigated at given times. Also, a comparison between the solutions in the cases of isothermal and adia-batic flows is made.展开更多
基金supported by the Ministry of Science and Higher Education of the Russian Federation,State Assignment No.GZ0110/23-10-IF。
文摘Luminosity outbursts of FU Ori-type objects(FUors)allow us to observe in the gas the molecules that are typically present in the ice in protoplanetary disks.In particular,the fraction of deuterated water,which is usually mostly frozen in the midplane of a protoplanetary disk,has been measured for the first time in the gas of the disk around FUor V883 Ori.We test the hypothesis that the observed high HDO/H_(2)O ratio in the V883 Ori protoplanetary disk can be explained by luminosity outbursts of different amplitude,including a series of two consecutive outbursts.Using the ANDES astrochemical code,we modeled the distributions of water and deuterated water abundances under the action of luminosity outbursts of different amplitudes(from 400 to10,000 L_(⊙))and at different stellar luminosities at the pre-outburst stage.We show that the best agreement with the observed HDO/H_(2)O profile is obtained for outburst amplitudes of 2000 and 10,000 L_(⊙),while the observed bolometric luminosity of V883 Ori does not exceed 400 L_(⊙).We discuss possible reasons for this discrepancy,including the presence of past luminosity outbursts,the age of the star,and the influence of additional heating mechanisms in the midplane of the protoplanetary disk.We also consider how the high observed HDO/H_(2)O ratio may be related to the evolution of the chemical composition of the ice in the protoplanetary disk and the chemical processes activated under outburst conditions.
文摘Non-similarity solutions are obtained for one-dimensional isothermal and adiabatic flow behind strong cylindrical shock wave propagation in a rotational ax-isymmetric dusty gas, which has a variable azimuthal and axial fluid velocity. The dusty gas is assumed to be a mixture of small solid particles and perfect gas. The equi-librium flow conditions are assumed to be maintained, and the density of the mixture is assumed to be varying and obeying an exponential law. The fluid velocities in the ambient medium are assumed to obey exponential laws. The shock wave moves with variable velocity. The effects of variation of the mass concentration of solid particles in the mixture, and the ratio of the density of solid particles to the initial density of the gas on the flow variables in the region behind the shock are investigated at given times. Also, a comparison between the solutions in the cases of isothermal and adia-batic flows is made.
