Astronomers Take to the Skies to View Meteor Shower

A team of world-class scientists, in collaboration with the University of Southern Queensland, has recently taken to the skies to study the cometary debris left after the fragmentation of the Schwassman-Wachman 3 comet. This was the first opportunity in recent history to observe debris from a newly fragmented comet, and the resulting meteor shower did not disappoint.  

Schwassman-Wachman 3 is a periodic comet that was discovered in 1930 as it passed just 9.3-million kilometres from Earth. In 1995 as it transited towards the Sun from the cold, outer reaches of the Solar system (as it does roughly every 5.4 years), its outer surfaces reacted to the Sun’s heating and the comet began to disintegrate.

Once a rock with a diameter of over 2-kilomteres, Schwassman-Wachman 3 has now split into around 70 main fragments with associated dust and debris. The fragments provide astronomers with an excellent opportunity to examine the cometary breakup process and shed some light on why some comets seem to disrupt more easily than others.

Each year as the Earth orbits through the plume of dust and debris left behind by Schwassman-Wachman 3 we are treated to a meteor shower known as the Tau Herculids. Generally, it is one of the less spectacular showers of the year, unable to match the Perseids in August or the Geminids in December in intensity. But some computer models suggested the Tau Herculids may be more of a meteor storm than a minor shower this year, and astronomers were able to organise an airborne observation mission on short notice.

“Although the potential meteor shower has been predicted for some time, the decision to fly an airborne observation mission was only made two weeks prior,” Dr Zander, a rocket scientist at the University of Southern Queensland and part of the scientific team, said.

“This demonstrates the capability and flexibility of the team to mount a complex airborne observation mission in a very short amount of time.”

The 3-hr flight took place on a Phenom 300 business jet, and the flight plan was designed to pass between several ground-based stations to allow triangulation of the meteors. Being around 40,000 feet above the Earth during the observations provided the team with some important advantages.

“By flying at a high altitude, we were able to detect significantly more meteors from the ground. We were able to avoid the significant atmospheric absorption which occurs due to the dense air at low altitudes, and we could see more sky which is restricted from the ground due to the curvature of the Earth.”

The team was able to capture data from hundreds of objects as they glowed brightly from the friction caused when they entered the atmosphere at speeds of around 12-km/s. The mission will help astronomers gain a better understanding of the composition of cometary objects, their physical properties, and their flight trajectories.

“From this mission, we hope to validate the modelling of the 1995 break-up event of the Schwassman-Wachmann 3 comet (the break-up was hypothesised to be quite unique), and using the spectral data we recorded gain insight into the composition of the comet. As this break-up was quite recent in astronomical terms, this is a rare opportunity to essentially see inside a comet,” said Dr Zander.

Of course, this is not the first time aircraft have been used for observational astronomy. Perhaps the best-known airborne mission is NASA’s SOFIA, the Stratospheric Observatory for Infrared Astronomy, which became fully operational in 2014. SOFIA can best be described as a 2.7-m diameter telescope built into the back of a Boeing 747SP, one that was previously operational at the airline Pan Am.

Over the years, SOFIA has observed the Moon, planets, stars, star-forming regions, and nearby galaxies. Among its many achievements was the discovery of water molecules on the sunlit side of the Moon in 2020. Unfortunately, SOFIA’s mission concludes in September this year, with NASA refocussing its priorities, and funding, elsewhere.

The recent mission to study Schwassman-Wachman 3 is proof enough that the era of airborne space observations will not be over with the retirement of SOFIA. As Dr Zander pointed out, aircraft provide a unique capability to observe various phenomena.

“The SOFIA aircraft was targeting more deep space measurements which are quite different to this. However, the future of our style of airborne observations is very promising. In addition to meteor showers, we also want to fly missions to measure space capsule re-entries, space debris, and hypersonic flight tests. Across all these areas there is a lot of data to be collected!”

This mission's success demonstrates Australia's sovereign capability to lead and execute internationally-significant research projects.