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In this paper we present optical long-slit spectroscopy and imaging of the protoplanetary nebula CRL 618. The optical lobes of CRL 618 consist of shock-excited gas, which emits many recombination and forbidden lines, and dust, which scatters light from the innermost regions.
The evolution and appearance of circumstellar disks in star forming regions can be influenced strongly by the radiation from nearby hot stars. Here we describe the results of numerical simulations of the evolution of protostellar disks and their immediate surroundings under the influence of external UV radiation.
The evolution and appearance of circumstellar disks in star forming regions are influenced strongly by the radiation from either the central star itself or close comparison and nearby hot stars.
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The James Clerk Maxwell Telescope has been used to obtain submillimeter and millimeter continuum photometry of a sample of 30 IRAS sources previously studied in molecular lines and centimeter radio continuum. All the sources have IRAS colours typical of very young stellar objects (YSOs) and are associated with dense gas.
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New speckle holographic images of the T Tauri infrared companion (T Tauri IRC; T Tauri S) reveal it to be a double system with a sky-projected separation of 0. 05, corresponding to a linear distance of 7 AU.
We present the first mid-infrared images of the circumstellar dust distribution around the supergiant star Alpha Scorpii.
We present alpha images of two objects, He 2-47 and M1-37, obtained during a Hubble Space Telescope imaging survey of young planetary nebulae (PNs) selected on the basis of their low-excitation characteristics.
We present Her imaging and molecular-line (CO) observations of He 2-113, an object which belongs to a rare class of planetary nebulae with Wolf-Rayet type central stars.
The detection of main-sequence circumstellar dust systems provides a powerful tool in the study of possible planetary systems similar to our own.
Using the Hubble Space Telescope, we have obtained Ha! imaging of the object Hen 2-90, which has long been classified as a planetary nebula (PN).
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Most planetary nebulae (PN) show significant departures from sperical symmetry, whereas the circumstellar envelopes (CSEs) of their progenitor AGB stars appear spherically symmetric.
We have obtained 800 and 1100 micrometer photometric observations of a complete, flux-limited, IRAS-selected sample of cold sources in Taurus, whose infrared and molecular properties indicate them to be low-mass protostars younger than T Tauri stars. The data were used to improve understanding of the role of the circumstellar envelope and disk during low-mass star formation and to search for signs of evolution.