Deep Impact: observations from a worldwide Earth-based campaign.

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

L1551NE-Discovery of a Binary Companion.

L1551NE is a very young (class 0 or I) low-mass protostar located close to the well-studied L1551 IRS 5. Here we present evidence, from 1.3 mm continuum interferometric observations at approximately 1&arcsec; resolution, for a binary companion to L1551NE.

The L1457 molecular/atomic cloud complex: H I and CO maps.

L1457 is the closest known molecular cloud (65 pc), and it lies near the edge of the local hot bubble and well out of the Galactic plane (b approximately -34 degrees). We have mapped an 8 degrees x 8 degrees region at 35' resolution and a 3 degrees x 5 degrees region at approximately 2' resolution in H I 21 cm emission. We have also mapped a 2 degrees x 4 degrees region at 2' resolution in 12CO J = 1-0.

High-resolution images of the L1551 bipolar outflow: evidence for an expanding, accelerated shell.

Approximately one-half of the L1551 bipolar outflow was mapped in the J = 1-0 transition of 12CO using the FCRAO 14 m telescope. The data were obtained by heavily oversampling over the beam area and then were reconstructed using a maximum entropy algorithm to obtain images of the high-velocity gas with an angular resolution of approximately 20". The outflow exhibits a striking shell-like structure with the lowest velocity out-flowing gas found along the limb of the outflow, and the highest velocity outflowing gas found along the axis of the outflow.

A revisit to the guest star of a.d. 185.

The guest star of A.D. 185 is possibly the earliest recorded supernova, and the radio source RCW 86 is believed to be its remnant.