The dM/dt of O-rich OH/IR Stars is Strongly Modulated

Details The dM/dt of O-rich OH/IR Stars is Strongly Modulated The dM/dt of O-rich OH/IR Stars is Strongly Modulated

Dec 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006aas...20910101l&link_type=abstract

2007 AAS/AAPT Joint Meeting, American Astronomical Society Meeting 209, #101.01; Bulletin of the American Astronomical Society,

Astronomy and Astrophysics

Astronomy

Scientific paper

Hubble images of the Cat's Eye and Egg nebulae exhibit concentric rings, so when they were AGB stars, their mass-loss rates were strongly modulated with a period of 100 years. Most OH/IR stars share this feature since:-
(1) The NIR colors of OH/IR stars fall on a tight locus in a two-color 2MASS plot, but the most massive objects with the reddest IRAS colors are widely distributed, instead of being at its red end, as would occur if shells were generated by a constant dM/dt. Our (AJ 132, 489) DUSTY models with a range of constant dM/dt or ages for detached shells both trace the locus when one uses a stellar SED matching its bluest colors and cold silicate dust. Hence the wide NIR color distribution of the thermally pulsing OH/IR stars with the reddest IRAS colors is an artifact of a modulated dM/dt.
(2) The resurrection of 1612 MHz masers in the OH/IR star IRAS 19479+2111. We (MN 364, 783 2005) successfully modelled Arecibo observations of the disappearance of 1612 MHz masers from OH/IR stars on a time-scale of a decade assuming a step decrease in dM/dt. We used a time-dependent model for the consequent changes in the OH column density and a radiative transfer code to follow the masers. The decline in the 1612 MHz masers is traced to changes in the 53 μm pump, consequent on changes in reprocessing of the stellar SED when dust in the zone around the dust-formation radius is removed by the ongoing expansion of the circumstellar shell. The reappearance of 1612 MHz masers in IRAS 19479+2111 (BAAS 37, 1335 2005) indicates the resumption of significant dM/dt and dust formation after a period of reduced dM/dt. This low mass star clearly experiences a strong modulation of its dM/dt.

Affiliated with

Also associated with

No associations

Rating

The dM/dt of O-rich OH/IR Stars is Strongly Modulated does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The dM/dt of O-rich OH/IR Stars is Strongly Modulated, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The dM/dt of O-rich OH/IR Stars is Strongly Modulated will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1159545