22 July 2004
Star in the making
In January this year, West Kentucky amateur astronomer Jay McNeil used a new 3-inch refracting telescope to take images of a familiar object, the M78 reflection nebula in Orion. When the images were processed he noticed an unfamiliar object nearby, now known as McNeil's nebula. A look back at images of this part of the sky revealed that in November 2003, a young low-mass star deep in the Lynds 1630 dark cloud had brightened suddenly, illuminating the soon-to-be-discovered nebula. Now a comparison of current X-ray spectroscopy images with data obtained before the optical outburst shows that there was also a 50-fold increase in X-ray emissions. Optical outbursts of the type seen from this star, V1647 Orionis, are usually associated with a rapid accretion episode. The X-ray emission probably stems from the high-energy accretion, and may therefore prove to be short-lived. Intriguingly, McNeil's nebula is not present on images taken in the 1990s and as early as 1951, but it has been found in mid-1960s material, so could be a consequence of a variable event.
An X-ray outburst from the rapidly accreting
young star that illuminates McNeil's nebula
J. H. KASTNER, M. RICHMOND, N. GROSSO, D. A. WEINTRAUB,
T. SIMON, A. FRANK, K. HAMAGUCHI, H. OZAWA & A. HENDEN
Nature 430, 429–431 (2004); doi:10.1038/nature02747
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