ProfessorPeter Tuthill

Project Opportunities

Title: Searching for Tatooine: the PAVO Planet Hunt

Summary of opportunity:

This project is one of the first to hunt for planets in orbit around double-star systems, and it will use a pioneering approach in advanced instrumentation to achieve an unprecedented sensitivity in revealing distant worlds.

Opportunity synopsis:

The new PAVO instruments, just brought online at the SUSI and CHARA arrays, have now achieved the highest sensitivity and resolution ever obtained. With this PhD project, you will develop a new astrometric interferometer mode for PAVO at the SUSI telescope which will probe nearby bright binary star systems for planetary companions. Double star systems have been largely overlooked in conventional planet hunts to date for which they are problematic, but our high precision methods exploit the properties of the binary to make the extremely high precision measurements needed to reveal the presence of planets. This challenging and ambitious project is among the key objectives for the facility. You will participate in the design and construction of advanced optical instrumentation, and then set the experiment in motion by leading an observational program targeting a handful of bright southern binary stars. Success in finding a planet in even one of these systems would be a signature result, commanding attention from the astronomical community worldwide.

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Project Opportunities

Title: Galactic Paleontology with Metal Poor Stars

Summary of opportunity:

Metal-poor stars are fascinating relics coming to us across vast shores of time from the ancient cosmos. In this project, we will make the first ever detailed study of their basic properties: temperature, radius and mass.

Opportunity synopsis:

Ultra metal-poor stars are the living fossils of the stellar kingdom. Although elements heavier than Helium only make up a tiny fraction of any star, they have a profound effect on the stellar structure.
Consequently stars born when the universe was substantially younger, before heavy elements were formed, should stand out from the crowd exhibiting dramatically different physical and thermal structure -- or so the theoretical models tell us. Because these fossil stars are rare and far from Earth, nobody has ever been able to examine one in detail. Until now. Your job in this project will put these stars under the microscope using the most powerful imaging arrays ever built: The Sydney University Stellar Interferometer and the CHARA array in Southern California. In making the first accurate measurements of the basic properties of metal-poor stars, you will determine whether these exotic objects are indeed as weird as theorists predict. The project then takes direct aim at one of the key questions in cosmology: the lithium abundance of very old stars is significantly lower than Big-Bang nucleosynthesis predicts. Where is the missing Lithium hiding, or is this a chink in the armour for Big-Bang cosmology?

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Project Opportunities

Title: The Stellar Surface Imaging Project

Summary of opportunity:

Our powerful new PAVO optical instrument will be used to make the first ever detailed images of the actual surfaces of distant stars. In this project, you will target some of the most spectacular stellar performers displaying bizarre physics such as magnetic stars with huge dark patches, and rotationally/tidally distorted stars.

Opportunity synopsis:

The twin PAVO instruments (PAVO is the Southern constellation of the Peacock) have just been commissioned at the SUSI (NSW) and CHARA (California) arrays. These instruments now set the standard for sensitivity and resolution in optical interferometic imaging, for the first time enabling us to answer a question which countless generations must have dreamed about: “What would it look like if I could zoom up to see a distant star at close quarters?”.  The sunspots and prominences exhibited by our own sun may be quite tame in comparison with the fireworks displayed by many of the exotic stars in our galaxy. The surfaces of several classes of strongly magnetic star should show strong surface mottling, with spectacular patterns of light and dark regions criss-crossing the stellar disk. Still other stars are distorted from the normal circular disk by rotation rates approaching break-up, or by tidal effects from an extremely close binary companion star stretching the surface into an egg shape. New observations, for the first time enabled by the PAVO instruments, will open a unique new window into the exotic physics which governs such extreme astrophysical environments. In this project, you will learn about design of leading edge astronomical instrumentation, construct your own observing program and conduct observations at both the SUSI array in Narrabri and the CHARA array in California.

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Project Opportunities

Title: The Riddle of the Red Square

Summary of opportunity:

This project is a detailed study of one of the most fascinating new nebulae to be discovered in recent years by Astronomers: The Red Square. As a likely imminent supernova precursor, this system may give us the best example of a structure which may be responsible for the ring system seen in the only naked-eye supernova in living memory: SN 1987A.

Opportunity synopsis:

The ``Red Square'' is a spectacular, newly-discovered bipolar nebula (Tuthill et al, Science 2007). Using cutting-edge imaging techniques such as Adaptive Optics and Optical Interferometry implemented at some of the world’s largest observatories (e.g. Keck, Gemini), we have revealed beautiful and startlingly detailed structures. A striking set of rungs crossing the nebula imply the existence of a highly regular series of nested bicones: possibly a relic of previous episodes of eruption or instability in the host star MWC 922 at the heart of the system. What is particularly compelling about this object is the correspondence between the sharp rung structures we see in The Red Square, and the beautiful polar rings now exhibited by the only naked-eye supernova since the invention of the telescope: SN 1987A. The origin of these mysterious rings stands out as one of the foremost unsolved problems in Supernova astronomy, and in the Red Square, we may have found the best example of a candidate progenitor for these structures. For this project, you will unravel the physics of this fascinating target and participate in new observing programs for the Keck telescopes (Hawaii) and VLT telescopes (Chile). In revealing the true nature of the enigmatic star MWC 922, we hope to solidify the links between this new nebula and the relic structures around SN 1987A.

----------Current Research Projects----------

Project Opportunities for PhD or Masters in Physics/Astrophysics

• Imaging Newborn Exoplanets
• Interferometry with the JWST space telescope
• Peering into the cradle with VAMPIRES
• The stellar surface imaging project
• The Riddle of the Red Square
• Galactic Paleontology with Metal Poor Stars