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SHOOTING STARS Masers from red giants

S. Ramstedt ; Wouter Vlemmings (Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik) ; E. Humphreys ; F. Alves
Proceedings of the International Astronomical Union; Cosmic Masers - from OH to Ho (1743-9213). Vol. 8 (2012), S287, p. 292 - 293.
[Konferensbidrag, övrigt]

SiO maser emission probes the region close to the stellar surface where the wind is formed and is observed to better constrain the physical conditions in this region. We have started a long-term project where high-excitation 28SiO maser lines (i.e., J=5-4, v=1 and 2) are observed in a large sample of southern AGB stars. The primary goals are to put constraints on the physical conditions in the extended atmospheres, and to achieve a better understanding of the maser excitation process. Since the maser emission is strong and often highly linearly polarized, the detected sources could also complement the polarization calibrator catalogue for ALMA. Preliminary results show a high detection rate and that in approximately 20% of the sources, the v=2 transition emits stronger than the v=1 transition. We interpret this as possibly indicative of a hot dust shell very close to the stars.

Nyckelord: masers; polarization; catalogs; stars: AGB and post-AGB; stars: mass loss

Sofia Ramstedt, Wouter Vlemmings, Elizabeth Humphreys and Felipe Alves (2012). SHOOTING STARS Masers from red giants. Proceedings of the International Astronomical Union, 8, pp 292-293 doi:10.1017/S1743921312007193

Denna post skapades 2012-11-01. Senast ändrad 2014-09-02.
CPL Pubid: 165370