Nearest supernova in a decade confirms such stars lose mass prior to exploding

Gemini North image of supernova in Pinwheel Galaxy
Arrow points to supernova. Click for original image,
taken by the Gemini North telescope in Hawaii.

Astronomers making a detailed analysis of the data from the nearest supernova in a decade, SN 2023ixf and located in the Pinwheel Galaxy only 20 million light years away, has confirmed what other research had suggested, that such stars lose significant mass prior to exploding.

Within hours of going supernova, core-collapse supernovae produce a flash of light that occurs when the shock wave from the explosion reaches the outer edge of the star. SN 2023ixf, however, produced a light curve that didn’t seem to fit this expected behavior. To better understand SN 2023ixf’s shock breakout, a team of scientists led by CfA postdoctoral fellow Daichi Hiramatsu analyzed data from the 1.5m Tillinghast Telescope, 1.2m telescope, and MMT at the Fred Lawrence Whipple Observatory, a CfA facility located in Arizona, as well as data from the Global Supernova Project— a key project of the Las Cumbres Observatory, NASA’s Neil Gehrels Swift Observatory, and many others. This multi-wavelength study, which was published this week in The Astrophysical Journal Letters, revealed that, in sharp contradiction to expectations and stellar evolution theory, SN 2023ixf’s shock breakout was delayed by several days.

“The delayed shock breakout is direct evidence for the presence of dense material from recent mass loss,” said Hiramatsu, adding that such extreme mass loss is atypical of Type II supernovae. “Our new observations revealed a significant and unexpected amount of mass loss— close to the mass of the Sun— in the final year prior to explosion.”

The press release overstates the surprise of this discovery. Research in the last two decades of massive stars that are thought to be the progenitors of supernovae has shown that they lose mass in great amounts during eruptions. It was therefore not that surprising that this star experienced its own eruption prior to going supernova.

Gemini telescope in Hawaii fixed, captures nearby supernova

Gemini North image of supernova in Pinwheel Galaxy
Click for original image.

The Gemini telescope in Hawaii, which was damaged in 2022 during normal maintenance operations, has now been fixed and resumed observations, beginning with a spectacular image of the newly discovered supernova in the Pinwheel Galaxy, only 20 million light years away.

The Gemini North telescope, one half of the International Gemini Observatory operated by NSF’s NOIRLab, has returned from a seven-month hiatus literally with a bang, as it has captured the spectacular aftermath of a supernova, a massive star that exploded in the large, face-on, spiral Pinwheel Galaxy (Messier 101). The supernova, named SN 2023ixf [as indicated by the arrow], was discovered on 19 May by amateur astronomer Koichi Itagaki.

Since its discovery, observers around the globe have pointed their telescopes toward Messier 101 to get a look at the burst of light. Over the coming months, Gemini North will allow astronomers to study how the light from the supernova fades and how its spectrum evolves over time, helping astronomers better understand the physics of such explosions.

As one of the closest supernova to occur in years, SN 2023ixf has become a major target by astronomers. This type of supernova signals the collapse and death of a star 8 to 10 times the mass of the Sun. Since the life cycle of such massive stars is not yet fully understood, this nearby supernova provides a great opportunity for astronomers to learn more.

Watch a still brightening new supernova only 20 million light years away

A new still brightening supernova has been discovered in the Pinwheel Galaxy, also known as Messier 101, only 20 million light years away, one of the closest such supernovae in years.

The discovery was made on May 19, 2023. Because the supernova is so close, it was discovered very early in its explosion and is still brightening to maximum. It is also an object that ordinary amateur astronomers can spot using their own telescopes. The Pinwheel Galaxy is located in the Big Dipper, making it a good target for amateurs in the northern hemisphere.

A live stream of the supernovae, dubbed SN 2023ixf, is also being broadcast today by the Virtual Telescope Project, and will be available here starting at 3 pm (Pacific).

No supernovae have occurred within our own galaxy, the Milky Way, since the invention of the telescope, so any such event in a nearby galaxy is an important opportunity for astronomers to learn more about these explosions.