Nestled within the open star cluster Messier 37, an enigmatic object situated 4,500 light-years away from Earth may offer a glimpse into our future 5 billion years from now. According to Space.com, it’s a stunning planetary nebula with a white dwarf at its core, and it represents the remnants of a relatively recent “stellar death.”
Messier 37 star cluster, home to an intriguing planetary nebula – Image: Klaus Tubingen and colleagues
The term “planetary nebula” is a long-standing misnomer, referring to a cloud of gas and dust left behind by an exploded star. This intriguing object was discovered by a research team led by GS Werner at the University of Tübingen, Germany. It promises to provide insights into the fate of our Solar System, including Earth, five billion years from now.
This marks the point in time when scientists estimate that our Sun, our parent star, will have exhausted its energy reserves. Initially, it will expand into a red giant, swallowing up several nearby planets, including our own. Subsequently, the star, along with the engulfed planets, will undergo a cataclysmic explosion before collapsing into a white dwarf.
The planetary nebula within Messier 37, with a white dwarf at its center and a spherical cloud of debris, gas, and dust, indirectly portrays that future scenario. Stellar deaths have long been known but still hold many mysteries. One aspect yet to be fully understood is the relationship between a star’s initial mass and its eventual fate.
While stars like our Sun lose only about half of their mass, larger stars, eight times or more massive, can lose up to 80% of their mass. GS Werner argues that this may be due to heavier stars consuming nuclear core fuel more rapidly by fusing hydrogen into helium, thus leading to a shorter lifespan and quicker evolution into a white dwarf.
The white dwarf within the recently discovered planetary nebula has a mass approximately 85% that of the Sun, estimated at 2.8 solar masses during its prime. As a large star, it lost around 70% of its mass upon its death. Its surface also lacks hydrogen, suggesting it underwent a violent event, akin to a supernova explosion, which gave rise to the planetary nebula. Supernovae supply the necessary material to form the next generation of stars and, as such, provide a piece of the puzzle on how the universe has evolved.
Hence, the planetary nebula nestled within Messier 37 not only tells the story of our future but also contributes to our understanding of how the cosmos has unfolded.