Engineering topics
Publications and source records attributed to Tereby, S..
A concept study was performed in 1994 to develop a mission design for a telescope to achieve the highest possible spatial resolution in the 10-30 micron range within a $200 million mission cost cap. The selected approach for the resulting Mid-Infrared Optimized Resolution Spacecraft (MIRORS) concept design utilizes a partially filled five meter aperture.
High spatial resolution observations are presented of the compact outflows associated with the young protostars TMC1 (IRAS 04381+2535) in Taurus. Emission in CO (1-0) imaged with the Owens Valley millimeter array shows the outflow lobes to be conical close to the star. Analysis of the outflow dynamics indicates that these objects are low-luminosity versions of the energetic outflows more commonly observed.
The class 0 sources form an interesting new category of protostellar objects. Many have strong millimeter continuum emission and exhibit jetlike outflows. There are suggestions that these objects are systematically younger than typical embedded (class I) sources. We are investigating the properties of class 0 sources to determine whether they are indeed very young or perhaps represent extreme physical conditions, such as rapid rotation. We present millimeter interferometric data for the class 0 object known as L1448 IRS3. This young low-mass star has extremely strong millimeter continuum emission. The interferometer data show the emission is resolved on a scale of a few arcseconds (1000 AU) This suggests the bulk of the dust continuum emission originates in an 'infall' envelope rather than a protostar disk. In addition, the C180 line data display a strong velocity gradiant which indicates the dense core is rapidly rotating. We compare our data with the predictions of protostellar collapse models.
Solutions that describe the collapse of a molecular cloud core that is initially in unstable equilibrium, embedded within an envelope of uniform density, and rotating at the same rate as the envelope are given. Hydrodynamic equations, including self gravity, are deduced to a set of ordinary differential equations, which are solved by the method of matched asymptotic expansions. Results of these calculations are: (1) the range of stellar masses derived seems to correspond to realistic ranges of observed stellar masses and interstellar cloud parameters, (2) the proper measure of dissipation rate is the ratio of accretion time to viscous diffusion time, and (3) the pressure distribution on the surface of an accreting protostar is nonuniform in a way that favors the channeling of a stellar wind into a bipolar flow directed along the rotation axis.