Chris Tinney's Research Projects - Exoplanets and Brown Dwarfs

Project ID: 



Chris Tinney



Working with Veloce Rosso - Australia's Exoplanet Foundry


The $3m Veloce Rosso will go into operation at the 3.9m Anglo-Australian Telescope in early 2017. It is specifically designed to be able to measure masses for low-mass, potentially habitable planets rbiting cool M-dwarf stars, as discovered by NASA's Transiting Exoplanet Survey Satellite mission. Veloce is a precision Dopler spetcroagraph that detects exoplanets by searching for the reflex Doppler wobble the induce in their host star, at velocities of less than 1m/s up to over 100 m/s.


Honours studenrs can be involved in undertaking observations with this instrument, developing calibration techniques, analysing data, and publishing results on new exoplanet detections and mass measurements.





Exploiting the FunnelWeb Survey


The FunnelWeb survey will start operation in Nov 2017, and will undertake a ground-breaking survey of all of the bright stars in the Southern Sky. It is remarkable that the brightest stars – while the easiest to observe – have remained amongst the most poorly characterised. The largest extant all-sky spectroscopic star catalogue (the Henry Draper Catalogue with ~ 300,000 stars) was compiled using photographic material between 1918 and 1936 and extends down to only 9th magnitude. However, over the last 2 decades the focus of the highest priority science in astronomy has shifted to exactly this range between 9th and 14th magnitude. The time is therefore right for a major survey that can target these stars.



The FunnelWeb survey seeks to create the "HD Catalogue of the 21st century" by obtaining a spectrum for every stars in the southern sky down to I=12, supplemented by a spectrum of every object that might be an M-dwarf down to I=14. This is made possible by the TAIPAN spectrograph using the revolutionary new Starbug technology developed at the Australian Astronomical Observatory. TAIPAN can reposition its 150 on-sky apertures for the observation of a new field of targets in just minutes. This enables observations of large numbers of fields with short exposures so that TAIPAN can obtain moderate-resolution spectroscopy (λ/Δλ ≈ 2300) for huge numbers of bright stars. This capability makes possible a survey of unprecedented scale and scope in just a few years, obtaining spectra for millions of stars distributed over the entire sky accessible from the South.



NASA TESS Exoplanet mission


FunnelWeb strategically links critically with NASA's next exoplanet survey mission - TESS. NASA’s Kepler mission has revolutionised our knowledge of the Galaxy’s stars and planets‡. But it has its problems, which include observing only faint stars clustered in a single northern field. Even more critically, its target stars were barely characterised when Kepler launched, and remain so to this day. Since what we know about Kepler’s planets relies on how well we understand its stars, this is a serious issue. The TESS satellite – with its all-sky survey of brighter stars that can be more readily followed up – is set to once more revolutionise our understanding of exoplanets (planets orbiting other stars). But for TESS to fully exploit its potential, its target stars must be fully characterised. 


TESS mission scanning on sky

Figure: Left. | The instantaneous combined field of view of the four TESS cameras. Middle. | Division of the celestial sphere into 26 observation sectors (13 per hemisphere). Right. | Duration of observations on the celestial sphere, taking into account the overlap between sectors. The dashed black circle encloses the ecliptic pole.




FunnelWeb can obtain a high-quality spectrum for every southern star that TESS can observe, delivering an input catalogue that (a) contains no giants or double-lined spectroscopic binaries around which exoplanets cannot be found, and (b) provides a stellar temperature, surface gravity, metallicity and radial velocity in advance for every star that TESS can observe. This will make it possible to interpret TESS results on planet frequency and system architectures as a function of host star mass, age, and stellar population in a direct and rapid way that has been problematic for Kepler without the investment of hundreds of nights of large telescope time (valued at tens of millions of dollars). FunnelWeb can carry out those characterization observations in advance of TESS launching for a fraction of this cost.




FunnelWeb will provide critical input data for a variety of exoplanetary science projects by using the FunnelWeb sectra to hunt for rare and otherwise difficult to find types of star.

  1. The Hunt for Young Stars suitable for use as direct imaging targets for exoplanets.
  2. Provision of Sun-like Target stars for the NASA TESS mission, delivering short-period transiting gas- and ice-giant planets suitable for follow-up to determine masses, densities, and spin-orbit alignments.
  3. Provision of M-dwarf target stars for the NASA TESS mission, delivering transiting low-mass planets in the habitable zones of low-mass stars.
  4. Plus a Plethora of Galactic Structure, Binary star and Serendipitous Science

Honours students can work with Prof Tinney in any of these areas.




Finding the Cold Neighbours of our Sun


In 2014, it was announced that the NASA WISE satellite had discovered a previously unknown 250K brown dwarf just 2pc away from the Sun ( Despite detailed analysis of the WISE database, this object (WISE0855) had escaped detection due to a combination of a very large proper motion, and two fortuitous background objects that masked its ridiculously cold nature. In this project you would examine the WISE database looking for similar examples of objects that could have escaped previous detection, that can then be taken to the Magellan telescope for follow-up observation.

Artists conception of WISE J085510.83-071442.5, the coldest known brown dwarf

(Credit: NASA/JPL-Caltech/Penn State University)

Finding the Cold Neighbours of our Sun


Over the last 2 years, astronomers in the Exoplanetary Science at UNSW group led by Prof Chris Tinney have been studying a sample of the coolest Y-type brown dwarfs (objects with temperatures as cool as 400K) to measure their distances via trigonometric parallax.


In this project you will be using that data (acquired on the Magellan 6.5m telescope in Chile) to look for other objects in the field of view of the camera that share a common motion across the sky with the planetary-mass brown dwarfs we are studying.