If the dips are real, what causes them?
Seven answers, none aheadNone is ahead yet. See what would settle it.
Where it stands
Seven answers have been proposed. None is ahead on the evidence yet. Seven are still possible. Of the one narrower question under it, none is answered yet.
Why it matters
Every scenario the discoverers tried failed or needed special assumptions[1]. A shallow, random transiter would be either a new kind of planetary system or a new kind of stellar variability.
Answers 7
History
- Rappaport et al. puts forward: several planets, possibly with large transit-timing variations, around one or both stars.
- Rappaport et al. puts forward: a planet in a close binary (S-type, eccentric and precessing) or around a binary (P-type), whose transits are…
- Rappaport et al. puts forward: a disintegrating ultra-short-period planet whose dust tail is only sometimes thick enough to be seen.
- Rappaport et al. puts forward: many dust-emitting asteroids or planetesimals on different orbits.
- Rappaport et al. puts forward: dipper-star behaviour of the kind seen in young stars with disks, on star B and diluted by star A.
- Rappaport et al. puts forward: short-lived dark spots that appear within half an hour, last a few hours and vanish.
- Rappaport et al.: simulations of an eccentric S-type planet always left a detectable periodicity.Against: A planet in a close binary (S-type, eccentric and precessing) or around a binary (P-type), whose transits are…
- Rappaport et al.: only 7 per cent of more than 400 transits would show; simulations put this near the limit of detectability.Against: A disintegrating ultra-short-period planet whose dust tail is only sometimes thick enough to be seen.
- Rappaport et al.: almost all dips have similar depths, which many independent bodies are unlikely to produce.Against: Many dust-emitting asteroids or planetesimals on different orbits.
- Rappaport et al.: ten known dippers diluted by a factor of 15 do not resemble this light curve.Against: Dipper-star behaviour of the kind seen in young stars with disks, on star B and diluted by star A.
- Rappaport et al.: star B's possible infrared excess would be hidden by the dilution.For: Dipper-star behaviour of the kind seen in young stars with disks, on star B and diluted by star A.
- Rappaport et al.: the authors find no physical law violated and note such events could have gone unnoticed in other stars.For: Short-lived dark spots that appear within half an hour, last a few hours and vanish.
- Session 1: worked on one of its sub-questions