* Astronomy

Blobrana · L

RE: RCW 103

Blobrana · L

Title: Chandra Observations of SNR RCW 103
Author: Kari A. Frank (Penn State), David N. Burrows (Penn State), Sangwook Park (U of Texas at Arlington)

We analyze three Chandra observations, with a combined exposure time of 99 ks, of the Galactic supernova remnant RCW 103, a young supernova remnant, previously with no clear detection of metal-rich ejecta. Based on our imaging and spectral analyses of these deep Chandra data, we find evidence for metal-rich ejecta emission scattered throughout the remnant. X-ray emission from the shocked ejecta is generally weak, and the shocked circumstellar medium (CSM) is a largely dominant component across the entire remnant. The CSM component shows abundances of ~0.5 solar, while Ne, Mg, Si, S, and Fe abundances of the ejecta are up to a few times solar. Comparison of these ejecta abundances with yields from supernova nucleosynthesis models suggests, together with the existence of a central neutron star, a progenitor mass of ~18-20 solar masses, though the Fe/Si ratios are larger than predicted. The shocked CSM emission suggests a progenitor with high mass-loss rate and subsolar metallicity.

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Blobrana · L

Title: The extremely long period X-ray source in RCW 103: a descendant of Thorne-Zytkow Object?
Authors: X. W. Liu, R. X. Xu, G. J. Qiao, J. L. Han, Z. W. Han, X. D. Li

The spin evolution of the compact neutron core in a Thorne-Zytkow Object (TZO) is investigated to explore the origin of extremely long period X-ray source. It is found that the outflow would effectively take away angular momentum from the core when radiation pressure dominates the accretion process. Thus the compact core could quickly spin-down to the co-rotation period (e.g. several hours) within the massive envelope, in about 10^3 - 10^4 years. The compact core could become an extremely long period compact star if the envelope is disrupted by some powerful bursts or exhausted via the stellar wind. The 6.67-hour periodic modulation of the central compact object (CCO) in supernova remnant RCW 103 could be naturally understood as the descendant of a TZO.

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