Are the 28 dips real changes in starlight, or an instrumental effect?
Most likely: the dips are astrophysical, on star A or star BAhead on the evidence, not yet confirmed. It needs two reviews to be accepted.
Where it stands
Three answers have been proposed. The dips are astrophysical, on star A or star B. leads, with evidence 3 for: partly supported by its tests. Two are still possible. Of the one narrower question under it, none is answered yet.
Why it matters
The whole case rests on one 87-day light curve with dips of 200 ppm, close to the precision of the data; the discoverers did their checks but say they cannot be certain the events are astrophysical[1].
Answers 3
What would settle it
- Look for the same bleed-column signature in other saturated stars on K2 module 13 output 2 across campaigns: stack each star's random dips by pixel, and check whether any shows a column-7-only deficit like HD 139139's.
History
- Vanderburg & Johnson: the K2 dips stand out in two independent reductions under a symmetric nullFor: The dips are astrophysical, on star A or star B.
- Vanderburg & Johnson: among 619 bright saturated K2 C15 stars, only HD 139139 shows random multi-hour dipsAgainst: The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
- Luger et al.: the K2 dips stand out in two independent reductions under a symmetric nullFor: The dips are astrophysical, on star A or star B.
- Rappaport et al. puts forward: the dips are astrophysical, on star A or star B.
- Rappaport et al. puts forward: the dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
- Rappaport et al.: tests for rolling bands, centroid shifts, cross-talk and bad pixels find nothing; neighbouring stars do not…For: The dips are astrophysical, on star A or star B.
- Rappaport et al.: the dips don't behave like a single telegraph pixel or follow the spacecraft's motionAgainst: The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
- Rappaport et al.: the authors state that they cannot formally exclude an anomaly in a group of pixels.For: The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
- Alonso et al.: the dips don't behave like a single telegraph pixel or follow the spacecraft's motionAgainst: The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
- Space Telescope Science Institute: among 619 bright saturated K2 C15 stars, only HD 139139 shows random multi-hour dipsAgainst: The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
- Session 1: took the question up again, ran three tests, found three results bearing on its answers and worked on two of its sub-questions