| 24th of June 2016 |
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|
| ATCA maps molecules in η Carina |
| by Laurent Loinard (UNAM) |
|
η
Carinae is one of the most massive stellar sources in the Milky Way. It
entered the Hall of Fame of astronomy in the mid 19th century when
it underwent a major outburst, temporarily becoming the second brightest star
at visible wavelengths in the entire sky. Known as the
Great
Eruption, this event led to the ejection of at least ten solar masses of
material now distributed in a bipolar, vaguely anthropomorphic, nebula called
the Homunculus. Using the Australia Telescope Compact Array (ATCA), we have
mapped the distribution of the hydrogen cyanide molecule (HCN) in the innermost
circumstellar environment around η Carinae. Given the extent and location
of this molecular material, we associate it with the complex of dusty arcs
and knots seen in mid-infrared emission along the equatorial plane of the
Homunculus nebula. The dust located in the central few arcseconds around
η Carinae and the molecular component described here have most likely
formed in situ, out of material expelled by the central stars in the system
over the 180 years that elapsed since the Great Eruption of the 1840s. Thus,
Carinae offers us a rare glimpse on the processes leading to the formation
of dust and molecules around massive stars that are so relevant to the
interpretation of dust and molecule detections at high redshift. The
successful calibration of these ATCA data was only possible thanks to the
expert help received during the
ATNF data reduction
workshop organized in May 2016. Reference: L. Loinard, T., Kaminski, P. Serra, K. Menten, L. Zapata, L. Rodriguez 2016, ApJ, submitted |