What causes the slow fading of the star?
Most likely: a large, diffuse amount of circumstellar dust, more extended than the clumps that make the dipsAhead on the evidence, not yet confirmed. It needs two reviews to be accepted.
Where it stands
Four answers have been proposed. A large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips. leads, with evidence 2 for: partly supported by its tests. Three are still possible. Of the two narrower questions under it, none is answered yet.
Answers 4
History
- Wright & Sigurdsson puts forward: an interstellar cloud or other intervening material passing slowly across the line of sight.
- Wright & Sigurdsson: the star's reddening and narrow sodium absorption are consistent with the total long-term dimming.For: An interstellar cloud or other intervening material passing slowly across the line of sight.
- Meng et al. puts forward: a large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips.
- Metzger et al. puts forward: the star is returning to normal after swallowing a planet, which brightened it.
- Meng et al.: the fade from 2015 to 2016 is about 22 mmag per year in Swift bands and about 5 mmag per year at 3.6 to 4.5…For: A large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips.
- Meng et al.: the fade's colour dependence is consistent with circumstellar material.Against: The star is returning to normal after swallowing a planet, which brightened it.
- Meng et al.: the fade is less steep in wavelength than general interstellar extinction.Against: An interstellar cloud or other intervening material passing slowly across the line of sight.
- Schaefer et al.: the secular decline continued to 2018 at a varying rate.For: A large, diffuse amount of circumstellar dust, more extended than the clumps that make the dips.
- Session 1: worked on three of its sub-questions