Mysterious 900-year-old nebula mapped in stunning detail

Somewhere in deep space there is a beautiful space weed spewing its metaphorical pollen from its core at ridiculous speeds. For nearly 900 years, the powerful cosmic explosion that caused this weed to bloom remained a mystery. Now a modern telescope allows us to get a better look at the results.

It is actually a nebula called the Pa 30 nebula, and its shape has some eccentricities. In 2023, astronomers from Dartmouth College and Louisiana State University described matter is torn away from the explosion, clumping together into threads that sprout from the center like a tuft of dandelions. Following this research, other astronomers mapped these filaments for the first time.

Humanity’s interest in the nebula can be traced back to 1181, when astronomers in Japan and China recorded the sighting of a nova. Six months later it passed, but was not forgotten. In 2013, an amateur astronomer named Dana Patchik was looking at images taken by NASA’s now-decommissioned Wide-field Infrared Survey Explorer. He discovered a nebula in a region of space where a star could be located, 7,500 light-years from Earth, in the constellation Cassiopeia. Over the next decade, astronomers concluded that the Pa 30 nebula was likely the remnant of a supernova that ancient astronomers had witnessed many years ago.

Nebulae are brightly luminous and often gigantic collections of matter, such as ionized gas and cosmic dust. But not all nebulae are the same. Some consist of the remains of stars that die in powerful explosions. This is exactly what happened in the case of the Pa 30 nebula, and some of the results are unique among known nebulae. At its core there remains a remnant of the star that gave birth to it, with a surface temperature of 360,000 degrees Fahrenheit (200,000 Celsius). For reference, the surface temperature of our Sun is about 10,000 degrees Fahrenheit (5,500 Celsius). The star is also throwing material away from itself at a ridiculous rate of 620 miles (1,000 kilometers) per second.

“We found that the material in the filaments expands ballistically,” said Tim Cunningham, a NASA Hubble scientist at the Harvard-Smithsonian Center for Astrophysics, in his paper. statement. “This means that the material has not slowed down or accelerated since the explosion. From the measured velocities, looking back in time, it is almost certain that the explosion occurred in 1181.”

Cunningham and his colleagues wanted to get a better idea of ​​the shape of these threads. They turned to a device in Hawaii called the Keck Cosmic Web Imager (KCWI), which detects light in the visible spectrum. Different colors move with different amounts of energy. For example, blue has a relatively high energy level compared to red. The difference in energy allowed astronomers to determine which matter was moving towards Earth and which was moving away. The result was a three-dimensional map of the nebula’s filaments. The shape is asymmetrical, hinting that the original explosion was also asymmetrical. There is also a strange cavity of nothingness up to 3 light years wide between the star remnant in the middle and the filaments, which is likely the result of an explosion that destroyed all matter that was too close to its center. (It should be noted that the Pa 30 nebula is far from the only strange shaped celestial body.)

“A standard image of a supernova remnant would look like a static photograph of fireworks,” said Christopher Martin, a professor of physics at Caltech who worked on the follow-up study, which was published in the journal. Letters from an Astrophysical Journal. “KCWI gives us something of a ‘movie’ in that we can measure the movement of the embers of the explosion as they shoot outward from the central explosion.”

The question remains why this nebula took this shape. Cunningham said this could have happened because the shock wave condensed the flying dust into beams, but he wasn’t sure. Even after almost a millennium, some mysteries continue to persist.