On March 25, 2024, Dr. Hanjie Tan, a PhD student in astronomy in Prague, Czech Republic, discovered a comet in a photo. ESA/NASA Solar Heliosphere Observatory (SOHO) spacecraft confirmed to be the 5,000th comet discovered using SOHO data. Even though this observatory was not designed as a comet hunter, it took him 28 years in space to accomplish this milestone.

SOHO, a joint ESA and NASA mission, was launched in December 1995 to study the dynamics of the Sun and its outer atmosphere, called the corona.

spaceship Large angle spectroscopic coronagraph‘s instrument uses an artificial disk to block the sun’s bright light, allowing scientists to study the sun’s immediate corona and environment.

This will allow SOHO to do something that many other spacecraft cannot: see comets flying close to the Sun, known as sun-grazing comets or sungrazers.

Many of these comets only become bright when they are too close to the Sun to be seen by other observatories, otherwise they would go undetected and get lost in the bright glare of our star.

Astronomers had hoped that SOHO would discover a comet by chance during its mission, but the spacecraft’s comet-finding capabilities made it the most prolific comet detector in history, making it the most prolific comet detector known today. We have discovered more than half of the comets.

In fact, soon after the spacecraft launched, people around the world started spotting so many comets in images that mission scientists needed a way to track them all.

In the early 2000s, we launched the NASA-funded Sungrazer project to allow anyone to report comets they saw in SOHO images.

“When LASCO was launched, no one imagined that it would become the most prolific discoverer in history,” said Dr. Carl Battams, a research scientist at the U.S. Naval Research Laboratory who is the principal investigator for LASCO and the Sungraser program. Ta.

“The amount of data and science that has been returned is simply beyond our imagination.”

The 5,000th discovery was made by Hanjie Tang, an amateur astronomer from Guangzhou, China. He is currently completing his PhD in astronomy. Student in Prague, Czech Republic.

Tan has been part of the Sungrazer project since he was 13 years old and is one of the project’s youngest comet discoverers.

He discovered comet SOHO-5000 in images from LASCO’s C2 camera.

Unlike most SOHO comets, this one very likely survived the Sun’s passage.

It will pass approximately 8.2 million km (5.1 million miles) from the Sun. This is slightly farther from the Sun than the current orbit of NASA’s Parker Solar Probe.

“Since 2009, we have discovered more than 200 comets,” Tan said.

“I joined the Sungrazer Project because I love looking for comets.”

“It’s really exciting to be the first to see a comet that has been traveling through space for thousands of years brighten so close to the sun.”

SOHO-5000 is a small, short-period comet that belongs to the Marsden family of comets, named after Dr. Brian Marsden, who first recognized the group.

The Marsden Group was unknown until SOHO/LASCO discovered it.

This group is believed to be an ancient descendant. Comet 96P/Machholtz near the sunLASCO observes every 5.3 years.

Of SOHO’s 5,000 comets, only about 75 belong to this group.

“Looking at the statistics of 5,000 comets and their orbits and trajectories through space is a very unique data set and really valuable science,” Dr. Battams said.

“This is a testament to the countless hours project participants have put into this.”

“We simply could not have reached this milestone without the work of our project volunteers.”