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Finding Alien Worlds in Queensland -- A Decade of MINERVA-Australis

This paper reviews the first decade of MINERVA-Australis, the University of Southern Queensland's dedicated ground-based facility that has confirmed and characterized 40 new exoplanets by providing essential follow-up observations for NASA's TESS mission.

Original authors: Jonathan Horner, Robert A. Wittenmyer, Stephen R. Kane, John Kielkopf, Duncan Wright

Published 2026-05-08

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CC BY 4.0

Original authors: Jonathan Horner, Robert A. Wittenmyer, Stephen R. Kane, John Kielkopf, Duncan Wright

Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Imagine the universe as a giant, bustling city. For a long time, we only knew about our own neighborhood (the Solar System). But over the last 30 years, we've realized that almost every "house" (star) in this cosmic city has its own family of "pets" (planets). We've found over 6,000 of these alien worlds so far!

This paper is a celebration of a specific tool built in Queensland, Australia, to help us find and study these new neighbors. Here is the story of MINERVA-Australis, told in simple terms.

The Problem: Too Many Candidates, Not Enough Detectives

Think of NASA's TESS spacecraft as a giant, high-tech security camera sweeping across the entire night sky. It's incredibly good at spotting "winks" in the starlight—tiny dips in brightness that suggest a planet is passing in front of a star.

However, TESS is like a camera that takes a snapshot of a suspect but can't arrest them. It gives us a list of "suspects" (candidates), but we need ground-based telescopes to act as detectives to confirm they are real planets and not just tricks of the light.

A few years ago, astronomers realized a problem: TESS was going to find so many suspects that the world didn't have enough "detectives" (telescopes) to check them all. Most telescopes are shared tools; astronomers from many different fields have to fight over time to use them. There was a fear that TESS would find thousands of planets, but we wouldn't have the time or resources to confirm them.

The Solution: A Dedicated "Planet Squad"

To solve this, a team in Toowoomba, Queensland, built MINERVA-Australis.

Instead of building one massive, expensive, custom-made telescope (which is like buying a custom luxury limousine), they used a clever trick. They bought four identical, off-the-shelf telescopes (like buying four reliable, mass-produced sedans).

The "Ford Model T" Approach: By putting four of these smaller telescopes together, they created a light-collecting power equivalent to one giant 1.4-meter telescope, but for a fraction of the cost.
The Teamwork: Because they have four telescopes, they can do multiple things at once. One can measure the star's "wobble" (Radial Velocity), while another watches for the "wink" (Transit), all on the same night.
The Location: It's located on Mt. Kent, a spot with very dark skies just outside Toowoomba. Its location is perfect because it can see the southern sky (where TESS spends a lot of time) and can also watch stars while it's daytime in Europe and the Americas, filling in the gaps when other telescopes are sleeping.

The Results: A Decade of Success

Since it started working in 2018, MINERVA-Australis has been incredibly busy. Here is what they have found:

40 Confirmed Planets: They have helped confirm 40 new alien worlds.
The "Warm Sub-Saturn" (TOI-257b): A planet about the size of Saturn but orbiting a hot star. It's like a gas giant that's been baked in an oven.
The "Puffy" Planet (TOI-1842b): A planet that is huge but incredibly light—like a giant balloon made of cotton candy. It's so light it's one of the least dense planets ever found. The star it orbits is dying and getting brighter, so this planet is slowly being "whittled away" and will eventually be swallowed by its host star.
The "Hot Jupiter" (TOI-778b): A massive planet orbiting a very young, fast-spinning star. It's so close to its star that it's scorching hot, and its orbit is weirdly tilted, suggesting it might have been kicked into its current spot by another invisible planet.
The "Mini-Neptune" (HIP 94235 A b): A small, rocky/icy world orbiting a very young star. Finding planets around young stars is hard because the stars are "active" and noisy, but this team managed to do it.

Bonus Science: The "Legacy" Work

While their main job is checking TESS suspects, the team also uses their telescopes to keep an eye on old targets from a previous project called the Anglo-Australian Planet Search.

The Long Game: They are looking for "Jupiter twins"—planets that take decades to orbit their stars. This is like watching a snail race; you have to keep looking for a very long time to see the finish line. They recently found a planet with a very strange, stretched-out orbit, suggesting a chaotic history where planets might have crashed into each other long ago.
Binary Stars: They also study pairs of stars orbiting each other, helping to understand how these cosmic dance partners move and spin.

Why This Matters

The paper concludes that MINERVA-Australis is a massive success story. For a relatively small investment (about $6 million AUD), a regional university in Australia built a facility that is now a key part of the global effort to find alien worlds.

It proves you don't always need the biggest, most expensive machine to do great science. Sometimes, a smart, dedicated team with a few well-chosen tools can find more than the giants. As the authors say, they are just getting started, and with thousands of new candidates waiting in the wings, their "detective squad" has plenty of work to do for the next ten years.

Technical Summary: Finding Alien Worlds in Queensland – A Decade of MINERVA-Australis

Problem Statement
The exoplanet community faces a critical bottleneck in the "Exoplanet Era." While space-based missions like NASA's TESS (Transiting Exoplanet Survey Satellite) have identified thousands of candidate planets through the transit method, these discoveries require rigorous ground-based follow-up for confirmation and characterization. The primary challenge is the scarcity of dedicated facilities; most existing telescopes are shared instruments where astronomers from diverse fields compete for observing time. This lack of dedicated resources risks squandering the "harvest" of TESS candidates, leaving many potential planets unconfirmed or poorly characterized. Furthermore, there is a need to continue long-term radial velocity (RV) surveys to detect Jupiter-analog planets with multi-decade orbital periods, a legacy left by the Anglo-Australian Planet Search (AAPS) program.

Methodology and Facility Design
To address the resource gap, the MINERVA-Australis facility was constructed at the University of Southern Queensland's Mt Kent Observatory. The facility represents a shift from bespoke, single-mirror telescope construction to a "Ford Model T" approach, utilizing four off-the-shelf PlaneWave CDK-700 telescopes.

Architecture: The array consists of four 0.7-meter telescopes. By combining their light-collecting area, the facility achieves the equivalent of a single 1.4-meter monolithic telescope at a cost approximately one order of magnitude lower than a custom-built instrument.
Operational Modes: The telescopes can operate in two modes via a 45° tertiary flip mirror:
1. Photometric Mode: For transit observations using broadband optical and near-infrared filters.
2. Radial Velocity (RV) Mode: Light is fed via fiber optics to a high-resolution (R~80,000) spectrograph housed in a thermally stabilized (±0.01 K), vacuum-sealed class 100,000 cleanroom. The spectrograph utilizes an iodine cell for wavelength calibration to correct for instrumental variations.
Strategic Advantages: Located at 27.8°S, the facility offers access to the TESS continuous viewing zone in the southern sky while retaining visibility of targets up to 40°N. Its longitude allows for time-critical observations during daylight hours in the Americas, Europe, and Africa.
Performance: Since first light in 2018, the facility has achieved RV precision of ~10 m/s for TESS targets (V magnitude 10–11) and photometric precision of a few millimagnitudes.

Key Contributions and Results
Since its commissioning, MINERVA-Australis has been involved in the discovery and characterization of 40 confirmed exoplanets. Key contributions include:

TESS Follow-up: The facility has confirmed numerous TESS Objects of Interest (TOIs), often combining its data with observations from other global facilities (e.g., FEROS, HARPS, LCOGT, CHEOPS).
- TOI-257b: The first MINERVA-Australis-led discovery, a "warm sub-Saturn" with a mass of ~0.138 $M_J$ and density similar to Saturn.
- TOI-1842b: An extremely low-density ("puffy") planet (~0.214 $M_J$ , ~1.04 $R_J$ ) orbiting an evolved star, with a bulk density of ~0.252 g cm $^{-3}$ .
- TOI-778b: An ultra-hot Jupiter (~2.76 $M_J$ ) orbiting a rapidly rotating young star, characterized by a highly eccentric and misaligned orbit.
- HIP 94235 A b: A mini-Neptune (~3 $R_\oplus$ ) orbiting a young (120 Myr) Sun-like star in a binary system, representing one of the smallest planets found around such a young star.
- HIP 133103 b & c: Two small planets (~1.83 and ~2.40 $R_\oplus$ ) in a near 2:1 mean-motion resonance around a young K-dwarf.
Ancillary Science:
- AAPS-Legacy Survey: The facility continues the radial velocity legacy of the Anglo-Australian Planet Search. This led to the discovery of HD 83443 c, a massive (~1.35 $M_J$ ), highly eccentric ( $e \approx 0.76$ ) planet on a 22-year orbit, likely the result of a past scattering event in a system that also contains a hot Jupiter.
- Binary Star Characterization: Detailed RV and photometric studies of eclipsing binaries (e.g., TIC 48227288) to measure spin-orbit alignments, revealing potential misalignments that challenge current formation models.
- Rossiter-McLaughlin Effect: Measurement of the spin-orbit alignment for AU Mic b, the youngest planet to have such a measurement successfully achieved.

Significance and Claims
The paper asserts that MINERVA-Australis is Australia's only professional, dedicated exoplanet discovery and follow-up facility. Its significance lies in its cost-effectiveness and operational efficiency; for an investment of approximately $6 million AUD, the facility has become a pivotal component of the global effort to validate TESS candidates. The authors highlight that the facility progressed from construction to science data acquisition faster than any other precise RV instrument on Earth.

The paper claims that the facility has successfully mitigated the risk of TESS candidates being unconfirmed due to a lack of telescope time. By providing a dedicated, flexible array capable of simultaneous RV and photometric observations, MINERVA-Australis has secured a role in the global network, with NASA purchasing significant observing time to guarantee access for US institutions. The authors conclude that with over 7,700 TESS candidates still awaiting follow-up, the facility is well-positioned to continue its work for the next decade, while simultaneously expanding into legacy surveys and binary star dynamics.