SIMBAD references

2012A&A...543A.147R - Astronomy and Astrophysics, volume 543A, 147-147 (2012/7-1)

Searching for X-ray emission from AGB stars.

RAMSTEDT S., MONTEZ R., KASTNER J. and VLEMMINGS W.H.T.

Abstract (from CDS):

Magnetic fields have been measured around asymptotic giant branch (AGB) stars of all chemical types using maser polarization observations. If present, a large-scale magnetic field would lead to X-ray emission, which should be observable using current X-ray observatories. The aim is to search the archival data for AGB stars that are intrinsic X-ray emitters.We have searched the ROSAT, CXO, and XMM-Newton archives for serendipitous X-ray observations of a sample of ∼500 AGB stars. We specifically searched for the AGB stars detected with GALEX. The data is calibrated, analyzed and the X-ray luminosities and temperatures are estimated as functions of the circumstellar absorption. We identify 13 AGB stars as having either serendipitous or targeted observations in the X-ray data archives, however for a majority of the sources the detailed analysis show that the detections are questionable. Two new sources are detected by ROSAT: T Dra and R UMa. The spectral analysis suggests that the emission associated with these sources could be due to coronal activity or interaction across a binary system.Further observations of the detected sources are necessary to clearly determine the origin of the X-ray emission. Moreover, additional objects should be subject to targeted X-ray observations in order to achieve better constraints for the magnetic fields around AGB stars.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - stars: magnetic field - X-rays: stars

Simbad objects: 20

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2019.10.14-23:42:49

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