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Taking this few year window, the main sequence lifetime, and an optimistic estimate for the scale height of giant impact debris, and the number of Kepler stars observed, this suggests that every star would have to undergo 104 such impacts throughout its lifetime for us to be likely to witness one in the Kepler field.
“The history of astronomy tells us that every time we thought we had found a phenomenon due to the activities of extraterrestrials, we were wrong,” notes Institute astronomer Seth Shostak.
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Uit bijgesloten paper:
KIC8462852 displays two types of unique dimming episodes (the dips from Kepler and the fading from Harvard) and these must be causally related and coming from the same mechanism. That is, Ockhams Razor tells us that it is very unlikely that one star will suffer two different mechanisms that are unique to that star and that both are only manifest in dimming the starlight by up to 20%. The timescales differ greatly, from a day for the Kepler dips up to a century for the Harvard light curve fading. However, dimming events with intermediate time scales are also seen (e.g.,the1900-1909 decade and the last hundred days of the Kepler lightcurve), so apparently there is a continuum of time scales available for the one dimming mechanism. So if the day-long dips are caused by circumstellar dust occultations, then the century-long fading must also be caused by circumstellar dust occultations.
We re-analyze the same Harvard archival Johnson B photometry and find serious issues in the data processing techniques used for KIC8462852 ... A cross-check of other stars in the Kepler field of view shows similar data quality issues with a strong dependency on quality-cuts, leading to arbitrary results ... The most likely explanation for the century-long trend of KIC8462852 is thus a data artifact... . Our conclusion is that the analysis alone casts serious doubt on the idea of alinear trend for the star.
“In this case, we looked at variations in the brightness of a number of comparable stars in the DASCH database and found that many of them experienced a similar drop in intensity in the 1960’s. That indicates the drops were caused by changes in the instrumentation not by changes in the stars’ brightness.”
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Wellicht is het een planeet die uiteen gespat is door een botsing, of uiteen getrokken is door getijdenkrachten. Dan zou er relatief weinig gas kunnen zijn. De duur van de diepste delen van de eerste dip is minder dan een dag. Dat beperkt de kern van de wolk puin tot ongeveer 2 miljoen km diameter. Dan zou de puinwolk nog heel compact moeten zijn, en de catastrofe zeer recent.
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We propose that the secular dimming behavior is the result of the inspiral of a planetary body or bodies into KIC 8462852, which took place ∼ 10 − 104 years ago (depending on the planet mass). Gravitational energy released as the body inspirals into the outer layers of the star caused a temporary and unobserved brightening, from which the stellar flux is now returning to the quiescent state. The transient dimming events could then be due to obscuration by planetary debris from an earlier partial disruption of the same inspiraling bodie(s)
Dat het Keplerinstrument getuige is van zo'n zeldzame gebeurtenis laat nog voldoende grond voor twijfel over, maar dit lijkt mij inderdaad de meest plausibele verklaring tot op heden.Quote
But for the time being, the possibility that what are we seeing is the star returning to its normal state, and being occasionally dimmed by transiting pieces of debris, is the most plausible explanation yet.