scientific abstract most binary t tauri stars have separations of the same order as the size assumed for the circumstellar disks of these stars (one hundred or several hundred au). this proposal is to investigate a representative sample of t tauri binaries with separations ranging from less than one au to about 1000 au by means of multiband photometry from 3-200 micron. it is expected that interaction of the binary components with their circumstellar disks or their common circumbinary disk will reflect in the broad band energy distribution. by comparison with a sample of single stars (given by the isophot proposal evolution of disks around t tauri stars) we hope to see clear evidence for this interaction between the binary components and their disks and thus to provide necessary observational constraints for the dynamical evolution of these systems. the object list is taken from recent studies on the multiplicity of t tauri stars by simon et al.(1992), ghez et al.(1993), reipurth and zinnecker(1993) and leinert et al.(1993). our main selection criteria were to avoid confusion by neighboring t tauri stars and to avoid regions of strong cirrus emission. === summary === observation summary we propose to study three groups of binaries group 1. spectroscopic and close lunar occultation binaries with separations of at most a few au. group 2. binaries with separations around 10-50 au. group 3. binaries with separations exceeding the typical disk sizes of about 100 au. with progressively larger separations the interactions with the disks are expected to show at progressively longer wavelenghts. performance time overview observations priority 1 priority 2 priority 3 sum ------------------------------------------------------------------ broadband photometry --- 15096 s 1776 s 16872 s ------------------------------------------------------------------ (4.2 h) (0.5 h) (4.7 h) === detailed observing plan === the observations will be performed at 8 wavelengths between 3.6 micron and 90 micron in triangular chopping mode, and about half of the sources will be observed at 160 micron as well, using a five point raster. the size of the diaphragms is 52 arcsec for filters p_3.6 to p_25. there are no restrictions to the actual position angle of the chopping direction. the broad band photometry can be realized by two or three aots which are concatenated. our emphasis is on the accurate determination of the energy distribution at long wavelengths for sources with good iras detection, and on detecting the long wavelength emission for those sources with low or missing iras detection. with the given integration times the flux limit for a typical source brightness one of 0.3 jy is 10-30 mjy in the absence of cirrus (s/n about 10). cirrus confusion is about 100 mjy at a wavelength 100 micron for a cirrus brightness of 15 mjy/sr. with a typical far infrared source brightness of around 1 jy, again a s/n of about 10 results. filter t(on object) t(performance) diaphragm() chopthrow() ------------------------------------------------------------------ p_3.6 32 s 539 s 52 90 p_4.85 32 s 52 90 p_7.3 32 s 52 90 p_11.5 32 s 52 90 p_16 32 s 52 90 p_25 32 s 52 90 c_60 32 s 305 s 150 c_90 32 s 150 c_160 32 s 302 s --- raster scan --- acquisition 180 s -------------------------------------------------------------------
Instrument
PHT03 , PHT22 , PHT37 , PHT39
Temporal Coverage
1996-08-03T23:53:23Z/1997-03-01T22:24:26Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
