What’s the Buzz About Link Star? Why Scientists Are Thrilled About This “Teen Vampire” White Dwarf

Astronomers have identified “missing links,” manifested as a “teenage vampire” white dwarf, that connect the demise of a sun-like star to the formation of a white dwarf’s remnants.

However, this vampire isn’t after your blood. The specific white dwarf is known as Gaia22ayj and is situated approximately 8,150 light years from Earth, eagerly devouring plasma from its companion star. Stars.

The discovery team utilized the Zwicky Transient Facility (ZTF) at the Palomar Observatory in California to observe this white dwarf. Researchers scanned the nocturnal sky across the Northern Hemisphere, searching for “transient” astronomical phenomena that exhibit rapid variability.

Gaia22ayj first garnered the attention of astronomers due to its rapidly pulsating signals, leading to its initial classification as an isolated double white dwarf.

Yet, further observations of Gaia22ayj proved inconsistent with this classification, revealing it to be one of the most extreme pulsating objects documented, with a brightness surge of 700% in a mere 2 minutes.

This is because Gaia22ayj is actually a white dwarf that feeds off a companion star, existing in a rare and short-lived phase of its life cycle.

Understanding Your Dead Star

The demise of a star occurs when it exhausts its nuclear fusion fuel. Regardless of their end or what follows, their fate hinges on their mass.

A star exceeding eight solar masses undergoes a violent supernova explosion, potentially becoming a very dense neutron star or a black hole. Conversely, stars with a mass similar to our Sun will not “go Nova” but instead transform into a white dwarf after a more subdued end.

Our Sun is expected to undergo this transition in about 6 billion years after expelling most of its mass during its red giant phase, ultimately ending as a fading stellar remnant.

Nevertheless, nearly half of all stars analogous to the Sun have binary companions. If these companions approach too closely, the white dwarf can revitalize by siphoning stellar material. This mass transfer process is precisely what seems to be occurring between Gaia22ayj and its companion star.

Gaia22ayj initially perplexed astronomers, as the variations in light intensity—its light curve—were inconclusive for the binaries of the stripped double white dwarf.

This led Tony Rodriguez, a graduate student from the ZTF Stellar Group at Caltech, to reevaluate the nature of the light emissions. After compiling additional data, Rodriguez and colleagues deduced that Gaia22ayj is likely a white dwarf orbited by a “normal” low-mass star, rather than a second white dwarf. They also established that Gaia22ayj possesses significant magnetism, with its white dwarf component rotating rapidly.

This resemblance to a white dwarf pulsar—a highly magnetic deceased star that emits electromagnetic radiation like a cosmic lighthouse—was noted. However, the feeding behavior observed in Gaia22ayj is typically not associated with white dwarf pulsars.

The research team concluded that Gaia22ayj serves as a missing link in the life cycle of white dwarf pulsars, representing a rare and transient early stage for these celestial objects.

“We have already documented two infant systems with white dwarfs in binary configurations where rapid rotation generates strong magnetic fields. Moreover, we have witnessed numerous mature systems with slowly spinning white dwarf stars,” Rodriguez remarked in a statement.

“However, this is the first star we’ve encountered that has already developed a robust magnetic field while being in the ‘teenage’ phase, during which it starts concentrating material from its companion star,” he continued. “We’ve never observed a system demonstrating such rapid spinning activity, but it is notably slowing down as it accrues mass from its companion.”

This discovery is particularly thrilling given that this phase lasts only around 40 million years. While that might sound significant, it’s relatively brief compared to the lifespan of a sun-like star, which spans about 10 billion years before it transitions into a white dwarf. Thus, this “teenage phase” comprises merely 0.4% of the star’s overall lifespan. To put it in perspective, if the star were an average human, this teenage phase would last around 107 days.

There’s hardly enough time for rebellious decoration.

“Data obtained from the WM Keck Observatory provided compelling evidence of the system’s sturdy magnetic field and material concentration around the white dwarf,” Rodriguez explained. “Further insights gathered from specialized instruments at the Palomar Observatory indicated that the system is significantly decelerating.”

The findings from this research were published in February in the Publications of the Pacific Astronomical Association.

This article was originally published Space.com.