MHS Alumna a Star in Astronomy Research

By Catherine Cluett Pactol, Editor

When she was a freshman at Molokai High School in 2017, Mallory Go set her sights on the stars and proposed astronomy research that would become groundbreaking. She captured the first look at magnetic fields within the iconic and beautiful Horsehead Nebula. Six years later, a paper she co-authored has been published in an astronomy journal.

“[A nebula is] a big cloud of dust and the Horsehead Nebula is a very cold cloud of dust,” explained Go.

Horsehead Nebula with magnetic fields plotted. Credit Hwang et al. 2023

At the time, not much research existed on the Horsehead Nebula, which has a district and identifiable shape as its name describes.

“I randomly did a search for nebulas. I don’t know why those nebulas, thinking back now, but I saw the Horsehead Nebula and there’s very few but very stunning images of it,” said Go. “And I don’t think there’s a lot of research around it, so I chose that as my project and then I applied to Maunakea Scholars program and I was very pleasantly surprised when I got in.”

Maunakea Scholars allows Hawaii high school students interested in astronomy to propose research and get competitive telescope time atop Maunakea. A handful of Molokai students have been accepted to participate in the program.

Dr. Harriet Parsons, an astronomer with the East Asian Observatory and head of operations at the James Clerk Maxwell Telescope, became Go’s mentor.

Parsons said Go’s proposal was personally significant to her.

“Mallory was the one that came to me saying, ‘Let’s investigate this [Horsehead Nebula] further,’ and I thought, “‘Fantastic, yeah, absolutely,’” said Parsons. “I’ve had [a picture of the] Horsehead Nebula on my wall ever since I was a little girl and I was interested in astronomy. So for me… it was coming full cycle.”

Parsons describes the nebula as “a beautiful, beautiful region.”

In 2018, using the James Clerk Maxwell Telescope in 2018, Go obtained unique images of the Horsehead Nebula in polarized light — a technique astronomers use to reveal the magnetic field within a nebula. Despite the Horsehead being iconic among astronomers, Go was the first to propose this type of research.

Mallory Go, left, and Dr. Harriet Parsons at Molokai High science fair. Photo courtesy of Mallory Go.

Together, Go and Parsons used a new instrument called the POL-2, a polarimeter, which is able to take measurements of the alignment of interstellar dust that can be influenced by magnetic fields in space.

Parsons describes a nebula as a “stellar nursery.” It’s a place where stars are sometimes born, under the right conditions. Go investigated some particularly dense areas within the horse’s head that could indicate the beginnings of a star formation. 

“We thought there might be stars there because of the gravitational pull of that very dense lump in the throat,” Go said. “And stars form because of that very strong gravitational pressure and that makes it so compressed that eventually become a star.”

Parsons said it appears no stars are actually forming within the nebula as of now – but the research is no less significant.

“How do stars form out of gas and dust clouds? Are they influenced by stars that have been there before? For example, the Horsehead region has a star close by that is sculping that gas and dust material near it,” explained Parsons. “What we’re seeing in the Horsehead is there is a clump that could go on and form a star but right now it looks like it’s not going to form a star. When you form a star, you want gravity to overcome the forces of turbulence, magnetic pressure and thermal radiation and you really want gravity to win. Once gravity wins… a star can be born…. But what we’re finding is magnetic pressure in this environment is enough to keep this star from collapsing.”

Another piece of the puzzle is that everything astronomers observe in space is actually taking place in the past.

“When we do astronomy, we are looking back in time,” said Parsons. “This star is 1500 light years away. I don’t know what’s happened since then in that environment. Perhaps another part of this region has another star that might influence it. I think it looks pretty stable long term, but things may change.”

Along with exploring the possibility of a star forming within the nebula, Go and other researchers found that the horse’s head shape is due to the forces of nearby stars and nebulae, as indicated by the magnetic fields they mapped.

“The data are impressive and what they tell us is even more impressive,” said astronomer Dr Kate Pattle, from University College London (UCL), UK, who was also a co-author of the paper. “I am delighted that Mallory has given us the chance to work on such a beautiful and iconic region of the sky- – and what we’ve found helps us to understand why the Horsehead Nebula has the shape that it does. These observations tell us a story of two dense regions hidden in the Horsehead. We see a ridge of warm gas and dust — the head and mane of the horse – that is interacting with the ultraviolet photons from nearby bright young stars. But sheltered behind that ridge, we see a cold clump of dense material which we think will go on to form a new solar system like our own. What’s so new and exciting about these observations is that we get to see for the first time what the magnetic field within these regions is doing.”

Go explained that despite all the research she did on the Horsehead Nebula, she “couldn’t point out this out to my friends.”

“I should mention that you can’t see it from the naked eye, but if you look at Orion’s belt… under the eastern most star under the Orion Nebula, is where you see the Horsehead Nebula,” said Go.

“We’re so lucky to see such amazing views of the sky from here in Hawaii,” explained Parsons. “You’ll see… beautiful patches of lots of stars… But then you’ll also see dark patches, and those dark patches aren’t just holes in space. They’re just where there’s so much gas and dust that they’re blocking out the background starlight. So that’s what those dark patches come from. Those are dark clouds, and the Horsehead Nebula is a dark cloud.”

Go proposed her project as a freshmen in 2017, was accepted as a Maunakea Scholar, and gathered the data in 2018 and 2019 – all without ever stepping foot within the telescope.

Parsons said coincidentally in 2019, shortly before the pandemic hit, the James Clerk Maxwell Telescope switched to remote operation, in which astronomers don’t need to be present on Maunakea to execute their research.

“So the data itself was taken remotely, but [Go] requested it,” explained Parsons. “And that’s oftentimes… the key in any scientific project is questioning and it’s the ‘why.” It’s the, ‘Can we look at this?’ and that’s a bit of where the excitement comes from.”

Go presented her work at Molokai High’s science fair, and the data was shared with top astronomers in the field who perused the project further. They built on Go’s observations to perform a quantitative analysis of the strength and role of magnetic fields in the region.

But after wrapping up her project, Go didn’t hear anything more about it.

“I honestly thought they forgot about it, and I didn’t blame them because it was four years ago and with all of COVID and they definitely had other ongoing projects at their respective telescopes,” Go said of the astronomers. “So I said, ‘Well, that was a cool thing we had in 2018 and 2019. I thought that was the last I would hear of the Horsehead Nebula.”

Much to her surprise, Go said she got a call from Parsons over a month ago letting her know the paper about her research had been published in the Astronomical Journal.

“That was really wild,” Go said.

“I’m really thankful that I had the mentors and the teachers I had, who pushed for me to continue doing things that I was interested in,” she added.

Go graduated from Molokai High in 2021 and is now entering her junior year at Brown University. Go’s family owns Molokai Drugs, and as the daughter of a pharmacist and a dietician, she is pursuing a degree in public health.

This summer, she’s pursuing an internship that researches gestational diabetes in Asian, Asian American, and Pacific Islander (AAPI) communities.

“I think one of the main chronic conditions that kind of plagues Hawaii is diabetes,” she said. “That was really personal to me and that’s why I decided to pursuit it at Brown.”

She encourages other students not to be limited by their career goals but instead take opportunities to study what interests them.

“I really think that you should pursue things that you just think are cool and interesting because you only might get to do it once – like this [astronomy research],” she said. “So I definitely advise people to pursue their interests, no matter if it’s outside of their field or not.”

In doing so, Go has proved that the sky’s the limit for Molokai students.