We present the results of one-dimensional numerical simulations of SNR evolution in the in­homogeneous medium considering the effects of the evaporation of the cloud and the thermal conduction. We have included the effects of changing evaporation rate as a function of cloud size and the ambient temperature so that the clouds could be evaporated completely before they reach the center of the SNR. The heat conduction markedly changes the density distribution in the remnant interior. To explain the observed morphologies of the centrally peaked X-ray SNRs(for example W44), the maximal thermal conduction is required. However, this is unlikely due to the magnetic field and the turbulent motion. The effects of the evaporation of the cloud and the thermal conduction described here may explain the class of remnants observed to have centrally peaked X-ray emmision.

We have simulated the interaction of supernova remnants with constant ambient medium to explore the dynamics of Type Ia supernova remnant. We assumed the supernova ejecta density distribution of the central constant and the outer power-law density distribution(ρ∝γ−n) (ρ∝γ−n) . We have calculated four different cases with different n. By scaling the length and time scales from the initial parameters-ejecta mass, ejecta energy, the ambient density, we could compare effects of the different density distribution of the ejecta on the dynamics of the SNRs. The radius of the outer forward shock converges the Sedov-Talyor solution at t' = 2.3 when the swept-up mass is 8 times of the ejecta mass. On the other hand, the motion of the reverse shock are largely affected by n. The ejecta with smaller n takes comparably long time to thermalize the whole ejecta at t′≃5.3,Msw≃18Mej t′≃5.3,Msw≃18Mej . We have applied our calculated results to obtain the ejecta density distributions of Tycho and SN1006 with n≃6 n≃6 .

Sobolev approximation can be adopted to a macroscopic supersonic motion comparatively larger than a random (thermal) one. It has recently been applied not only to the winds of hot early type stars, but also to envelopes of late type giants and/or supergiants. However, since the ratio of wind velocity to stochastic one is comparatively small in the winds of these stars, the condition for applying the Sobolev approximation is not fulfilled any more. Therefore the validity of the Sobolev approximation must be checked. We have calculated exact P Cygni profiles with various velocity ratios, V∞/Vsto, using the accelerated lambda iteration method, comparing with those obtained by the Sobolev approximation. While the velocity ratio decrease, serious deviations have been occured over the whole line profile. When the gradual increase in the velocity structure happens near the surface of star, the amount of deviations become more serious even at the high velocity ratios. The investigations have been applied to observed UV line profile of CIV in the Copernicus spectrums of ʃ Puppis and NV of τ Sco. In case of τ Sco which has an expanding envelope with the gradual velocity increase in the inner region, The Sobolev approximation has given the serious deviations in the line profiles.

We introduce the National Science Curriculum issued by the Education Ministry in Korea. Astronomy should be given and taught as compulsory courses in Nature of elementary school, Science of middle school, General Science of high school, and as elective courses in Earth Science I, II. Astronomy concepts have been designed in sprial pattern. College levels of astronomy have been given as majoring in astronomy course, cultivating one for earth science pre-teacher students and cultural subjects for non-major students

We have solved the radiative transfer problem using a Sobolev approximation with an escape probability method in case of the supersonic expansion of a stellar envelope to an ambient medium. The radiation from the expanding envelope turns out to produce a P-Cygni type profile. In order to investigate the morphology of the theoretical P-Cygni type profile, we have treated V∞, Vsto, β(parameters for the velocity field), it and E(parameter for collisional effect) as model parameters. We have investigated that the velocity field and the mass loss rate affect the shapes of the P-Cygni type profiles most effectively. The secondarily important factors are V∞, Vsto. The collisional effect tends to make the total flux increased but not so much in magnitude. We have infered some physical parameters of 68 Cyg, HD24912, and ℇ persei such as V∞, M from the model calculation, which shows a good agreenment with the observational results.

The temperature calibration of stars by photometric parameters and spectral type is discussed, using the catalogue data of Cayrel de Strobel et al. (1985) and Morel et al. (1976). The H-R diagrams and the mass-luminosity relation of stars in this catalogue are presented in the [log(L/M)-log T e ]-and [ M b o l -log(L/M)]-planes, respectively, discussing the age of main sequence (MS) stars and giant stars. The age-metallicity relation of the nearby stars suggests the initial rapid enrichment of metal abundance.

NGC 7023 have been observed in ^(12)CO and ^(13)CO (J=1→ 0) molecular line emissions. It possesses bipolar molecular outflows which are moving out both eastward and westward in Right Ascension with a velocity range of ±9 ㎞s^(-1) with an inclination of ∼80° The mass loss rate is ∼10^(-5)M◎_(yr)^(-1) with an assumed stellar wind velocity of ∼100㎞s^(-1); the dynamical age of this outflow is ∼5.5×10⁴ years. The bipolar molecular outflows would be collimated by the molecular disk surrounding HD 200775, which is explained by either the velocity gradient of ∼0.25 ㎞s^(-1) are min^(-1) in the position-velocity map of ^(12)CO along the Declination or the peak temperature maps of both ^(12)CO and ^(12)CO. The outflows also yield high density regions at their ends, producing the region of the low mass star formation.