we plan to test the substellar nature of a selection of brown dwarf candidates in young (age under 10 myr), embedded clusters. we detected them in jhk surveys of the cores of rho ophiuchi and ngc 2024. they are the best brown dwarf candidates in these clouds, identified on the basis of a new method of analysis that fits the near ir photometry simultaneously to theoretical models and interstellar reddening. the method separates the effects determining the observed spectral energy distribution (sed) of stellar objects and provides a mass estimate, which ultimately determines the stellar or substellar nature. for iso observations, we selected objects indicated by our fits to lie well below the end of the main sequence (with mass 0.03-0.07 solar masses). we also rejected objects with strong ir excesses indicative of large amounts of circumstellar material, studied by some guaranteed time programme proposals. we want to determine the sed from 3 to 8 microns. together with the near ir points, these new data can tightly constrain the luminosity of these objects, with temperatures of 2500 k-3000 k. the iso data will either detect the photosphere or identify ir excess due to circumstellar material. as masses are most tightly constrained by luminosities, not near infrared colors, iso data will provide a critical test of whether these objects are truly young brown dwarfs. together with our ground based observations, we will have sufficient data to accurately determine temperature and luminosity, and hence masses, of the objects. broad band photometry with cam will accurately constrain the shape of the sed. we plan to observe in four bands in which there is valuable information unavailable from the ground. sw1 samples mostly the stellar photosphere. lw1 and lw2 provide an extended wavelength baseline for sampling the sed at high sensitivity. this permits a reliable disentangling of the factors causing... ir excess in the observed sed. lw4 gives a more accurate measurement of the circumstellar contribution for the brightest objects.
Instrument
CAM01
Temporal Coverage
1996-03-14T09:57:48Z/1996-09-07T00:30:23Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's 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.
