Astronomers have discovered a new star experiencing extreme dimming in our galaxy, and they're not sure what's causing it. It is much more dramatic than the dimming of Boyajian’s star, which shot to fame in 2016 for its still unexplained 22 percent dip in brightness. The discovery of the object is reported in the Monthly Notices of the Royal Astronomical Society.
The new star, known as EPIC 204376071, dimmed by up to 80 percent, and lasted for an entire day. The dip in brightness was quite sudden but the return to normal was much more gradual, which is intriguing as a dip in light usually indicates an object passing in front of a star.
The object that obscured the star – which is a young low-mass red dwarf just 16 percent the mass of the Sun and a quarter of its volume – doesn’t have to be particularly big, it just needs to fit the skewed light profile seen by the astronomers.
The asymmetric dip in light and the age of the star led the researchers to consider two different scenarios; either the star is orbited by dusty material that blocked the light (nicknamed the dust sheet model), or the mysterious dip was caused by the dusty disk of an orbiting ringed planet.
Graphic representation of the dusty disk scenario by redditor GrandpaFluffyClouds
Both scenarios can explain the feature but they are not the exact right fit for it. Having a permanent dusty feature would be very exciting but the team thinks that is unlikely. The star is only 10 million years old, and it might still be absorbing material from its neighborhood. For this reason, they consider it a one-off event.
For the planet with a ring scenario, the team expects the dusty disk to have a diameter 4.2 times the radius of the host star. The planet that hosts the ring would have to be about three times the mass of Jupiter and the ring would be roughly the same mass as Saturn’s. The only issue with this model is the timing of the object in the model. The simulation expected the potential planet to orbit once every 28 days but the researchers only spotted a dip once during 160 days of observations.
The mystery of this star is probably going to have to remain just that for a while. The team doesn’t expect it to be studied again in any planned short- or medium-term planet-hunting campaigns. Boyajian’s star faced the same issue, and the continued study of that object is all down to community crowdfunding.