The contact binary system KIC 9832227 is worth another look.
Astronomers have seen some incredible occurrences across space and time.
There are novae: fusion flares on white dwarf stars’ surfaces.
There are supernovae: explosive stellar cataclysms.
In between those two are a novel phenomenon: luminous red novae.
These outbursts persist for months, glowing and echoing in visible and infrared light.
V838 Monocerotis emitted a spectacular one in 2002.
The leading explanation is a mergeburst: when two stars, already in contact, merge into one.
The merging contact binaries V4332 Sagittarii and V1309 Scorpii created luminous red novae.
Such identifications led to a question, “can we predict the next luminous red nova?”
Perhaps: by observing contact binaries with quickening orbital periods.
As the period shortens, the two stars approach a merger.
When a critical “closeness” is reached, it triggers a luminous red nova.
The binary system KIC 9832227 looked perfect: a contact binary whose period is shortening.
A 2017 prediction, using new and archival data, indicated an upcoming merger in 2022.
However, a timing error was swiftly uncovered and corrected, negating the 2022 prediction.
Instead, the period first lengthened before recently shortening, presenting yet another mystery.
KIC 9832227 may eventually make a luminous red nova, but probably not in 2022.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Starts With A Bang is written by Ethan Siegel, Ph.D., author of Beyond The Galaxy, and Treknology: The Science of Star Trek from Tricorders to Warp Drive.