HD 139139 - Numerous strange aperiodic transit-like events

The Random Transiter -- EPIC 249706694/HD 139139
https://arxiv.org/abs/1906.11268

Quote :

We have identified a star, EPIC 249706694 (HD 139139), that was observed during K2 Campaign 15 with the Kepler extended mission that appears to exhibit 28 transit-like events over the course of the 87-day observation. The unusual aspect of these dips, all but two of which have depths of 200±80 ppm, is that they exhibit no periodicity, and their arrival times could just as well have been produced by a random number generator. We show that no more than four of the events can be part of a periodic sequence. We have done a number of data quality tests to ascertain that these dips are of astrophysical origin, and while we cannot be absolutely certain that this is so, they have all the hallmarks of astrophysical variability on one of two possible host stars (a likely bound pair) in the photometric aperture. We explore a number of ideas for the origin of these dips, including actual planet transits due to multiple or dust emitting planets, anomalously large TTVs, S- and P-type transits in binary systems, a collection of dust-emitting asteroids, `dipper-star' activity, and short-lived starspots. All transit scenarios that we have been able to conjure up appear to fail, while the intrinsic stellar variability hypothesis would be novel and untested.

Very weird but interesting ,I have never seen something like that

How bright is this star maybe RV bring some answer?

That kind of thing is pretty easy to look up in SIMBAD.
It has a magnitude of 9.84 ± 0.04 in V band according to SIMBAD.

Recent update:

Jean Schneider (2019) "What is Transiting HD 139139?"
https://iopscience.iop.org/article/10.3847/2515-5172/ab465c

RV limits are <10 m/s over 4 days. This rules out the 50 Jupiter mass "planet" scenario proposed in an earlier note.

Quote :

Finally, we clearly need more data (more transits, radial velocities and imaging).

Isn't that always the way these things go?

Brzycki et al. "Breakthrough Listen Follow-up of the Random Transiter (EPIC 249706694/HD 139139) with the Green Bank Telescope"
https://arxiv.org/abs/1910.03711

No transmissions detected. How surprising.