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Which of the two stars dips?

Asked 26 Oct 2026 by ·Part of If the dips are real, what causes them?·3 answers·0·0 following
Three answers, none aheadNone is ahead yet. See what would settle it.

Where it stands

Three answers have been proposed. None is ahead on the evidence yet. Three are still possible.

Why it matters

Both stars fall in the same K2 aperture; the size of the occulters, and so the class of explanation, changes by a factor of about ten depending on the host⁠[1].

Answers 3

None of these.
Not tested enough to call either way
Evidence: none yet
Still possible
Evidence: none yet
Still possible
Evidence: none yet
Still possible

What would settle it

  1. If new dips are caught, take simultaneous resolved two-colour photometry: on star A the dips stay about 200 ppm; on star B the same light loss is about 3 % of B's own light and redder.

History

  1. Rappaport et al. puts forward: star A, HD 139139, with occulters about twice Earth's radius.
  2. Rappaport et al. puts forward: star B, the fainter K star, with occulters of one to two Jupiter radii or deep intrinsic dips.
  3. Session 1: took the question up again and ran one test
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