Relative astrometry of the J=1-0, v=1 and v=2 SiO masers towards R Leonis Minoris using VERA - AstrophysicsReport as inadecuate




Relative astrometry of the J=1-0, v=1 and v=2 SiO masers towards R Leonis Minoris using VERA - Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: Oxygen-rich Asymptotic Giant Branch AGB stars are intense emitters of SiOand H$ 2$O maser lines at 43 J=1-0, v=1 and 2 and 22 GHz, respectively. VLBIobservations of the maser emission provides a unique tool to sample theinnermost layers of the circumstellar envelopes in AGB stars. Nevertheless, thedifficulties in achieving astrometrically aligned v=1 and v=2 SiO maser mapshave traditionally prevented a unique interpretation of the observations interms of physical underlying conditions, which depend on the nature of the SiOpumping mechanism.We have carried out observations of the SiO and H$ 2$O maser emission towardsRLMi, using the astrometric capabilities of VERA. Due to the too-weak emissionof the reference calibrator we had to develop a special method to accuratelyrelate the coordinates for both transitions. We present relativeastrometrically aligned v=1 and v=2 J=1-0 SiO maser maps, at multiple epochs,and discuss the astrophysical results. The incorporation of astrometricinformation into the maps of SiO masers challenges the weak points in thecurrent theoretical models, which will need further refinements to address theobservations results.



Author: M. J. Rioja, R. Dodson, R. Kamohara, F. Colomer, V. Bujarrabal, H. Kobayashi

Source: https://arxiv.org/



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