Signatures of Dust Around Stars

Disks containing dust debris are found around stars (see e.g. Fig. 6.6). These disks are believed to be equivalent to our Kuiper Belt. There seem to be two different types of such disks  

Stern and Shull, 1991 [325] reported on water Masers, red giants, and Oort Clouds around other stars. Solar like stars will evolve to Red Giants as soon as their hydrogen supply is exhausted in their central cores. This so-called post main sequence phase implies an increase in luminosity by a factor of 1000. Such an increase will certainly affect the Oort cloud bodies. If we assume that such clouds are common around solar-like stars, then the question arises whether we would be able to detect such processes in giant star outflows. 

The presence of water in these outflows is naturally explained by the destruction of volatile rich components that are expected in an Oort cloud like structure. 

The effect of heating and resultant radiation of any orbiting dust cloud particles around red giants should be also detectable in the IR. The Kuiper belt objects (KBO) start to sublimate because they are heated up to 170 K. This leads to an IR excess at 25 pm. 

Using IRAS data. Jura, 2005 [176] searched for IR-signatures. With the Spitzer telescope the IR excess was measured around first ascent red giants. The data showed that this radiation seems to be caused by interstellar cirrus and not by KBO like objects. If there is any KBO like structure around these stars, then it must be less massive than the Solar System s. 

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