A Photometrically and Morphologically Variable Infrared Nebula in L483

We present narrow and broad K-band observations of the Class 0/I source IRAS 18148-0440 that span 17 years. The infrared nebula associated with this protostar in the L483 dark cloud is both morphologically and photometrically variable on a time scale of only a few months. This nebula appears to be an infrared analogue to other well-known optically visible variable nebulae associated with young stars, such as Hubble's Variable Nebula. Along with Cepheus A, this is one of the first large variable nebulae to be found that is only visible in the infrared. The variability of this nebula is most likely due to changing illumination of the cloud rather than any motion of the structure in the nebula. Both morphological and photometric changes are observed on a time scale only a few times longer than the light crossing time of the nebula, suggesting very rapid intrinsic changes in the illumination of the nebula. Our narrow-band observations also found that H_2 knots are found nearly twice as far to the east of the source as to its west, and that H_2 emission extends farther east of the source than the previously known CO outflow.Comment: 19 pages, 6 figures, 1 tabl

Distribution of the 3.1 micron feature in Cepheus A

Near-IR absorption features produced by core-mantle dust grains are observed in many protostellar objects. The high spatial resolution observations (less or equal to 3 in.) could be helpful to monitor the expected changes of the features. Cep A/IRS 6 is a suitable candidate to carry out such a kind of study. It is located in an active star formation region and consists of a young object associated with an extended reflection nebula. The ice feature was observed in four positions of Cep A/IRS 6 with a 2.7 in. aperture. The observations were carried out at the IRTF using the cooled grating array spectrometer CGAS. The 2.4 to 3.8 micron spectra of two positions are presented

Answering the Call

This non-fiction story tells of the challenges of being a young medical student while faced with a family health crisis. It explores the burden of responsibility facing the medical profession, starting when the white coat is donned at the beginning of first year

New H2 Jets in Monoceros R2

We are presenting a wide-field image of the Mon R2 star forming region obtained with WFCAM on UKIRT in the 2.12 micron filter centered on the H2 1--0 S(1) emission line. We report the discovery of 15 new H2 jets in Mon R2 and two in L 1646 and confirm most of these discoveries using archival Spitzer IRAC 4.5 and 8.0 micron images. We find that many of these protostellar jets are found in projection against the outflow cavities of the huge CO outflow in Mon R2, suggesting that the jets may be associated with an episode of star formation in Mon R2 triggered by this large, but now fossil, outflow. We also study the spatial distribution of small, localized reflection nebulae and find that these are distributed in the same way as photometrically identified Class I sources.Comment: 46 pages with 19 figures. Accepted for publication in The Astronomical Journa