Astronomers Discover White Dwarf Consuming Pluto-Like Object

Astronomers using the Hubble Space Telescope have observed a white dwarf star, designated WD 1647+375, consuming the remnants of a Pluto-like object. This discovery, detailed in a paper published on September 18, 2023, in the Monthly Notices of the Royal Astronomical Society, reveals the intense cosmic processes taking place as dying stars interact with nearby celestial bodies.

The white dwarf, which is the core remnant of a dying star, was found to be “snacking” on fragments from an icy planet that once orbited in the local version of the Kuiper Belt. Researchers believe that the star’s gravitational force captured the icy planet, leading to its eventual destruction. Analysis of the debris indicated the presence of key elements such as carbon, sulfur, nitrogen, and oxygen, suggesting that the object may have contained water before its demise.

Unusual Chemical Signatures

Typically, the atmosphere of a white dwarf consists primarily of hydrogen and helium. However, WD 1647+375 exhibited an unusual abundance of volatiles, which are chemical substances with low melting points. This anomaly prompted the research team to investigate further. According to study lead author Snehalata Sahu, “White dwarfs act like cosmic crime scenes. When a planetesimal falls in, its elements leave chemical fingerprints in the star’s atmosphere, letting us reconstruct the identity of the ‘victim.’”

The team noted a significant amount of nitrogen in WD 1647+375’s atmosphere, a crucial indicator of icy worlds. Additionally, the star’s accumulation of oxygen was notably higher than expected if the consumed object had been rocky. “We know that Pluto’s surface is covered with nitrogen ices,” Sahu explained. “We think that the white dwarf accreted fragments of the crust and mantle of a dwarf planet.”

From Hubble’s ultraviolet signals, researchers determined that the star has been consuming this icy object for at least the last 13 years, at a staggering rate of approximately 440,925 pounds (200,000 kilograms) per second. This suggests that the original icy planet had a minimum diameter of about 3 miles (5 kilometers).

A Glimpse into Cosmic Evolution

This finding provides a unique perspective on both the history and future of cosmic systems. The researchers noted that comets and icy planetesimals like the one consumed by WD 1647+375 are crucial for delivering water and other volatiles to terrestrial planets in extrasolar systems, which is essential for the emergence of life.

The existence of such icy planetesimals opens avenues for further exploration, particularly with the recent interstellar comet 3I/ATLAS. Sahu remarked that, while WD 1647+375 serves as an intriguing case study, it also offers insights into the fate of our own solar system. “When our Sun eventually burns out and collapses into a white dwarf like WD 1647+375, the planets may face a similar fate as this icy planetesimal,” she stated. “If an alien observer looks into our solar system in the far future, they might see the same kind of remains we see today around this white dwarf.”

The implications of this research extend beyond our immediate understanding of white dwarfs and their interactions. They highlight the complex processes that govern the life cycles of stars and the potential for life-sustaining materials to be delivered to planets across the universe.