A5042962135- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Spectroscopy and Laser Applications
- Space Satellite Systems and Control
- Atomic and Molecular Physics
- Spectroscopy and Chemometric Analyses
- Magnetic properties of thin films
- Physics of Superconductivity and Magnetism
- Tribology and Lubrication Engineering
- Spacecraft and Cryogenic Technologies
- Infant Development and Preterm Care
- Atmospheric Ozone and Climate
- Birth, Development, and Health
- Galaxies: Formation, Evolution, Phenomena
- Colorectal Cancer Screening and Detection
- Scientific Research and Discoveries
- Maternal and Neonatal Healthcare
Australian National University
2016-2024
Uppsala University
2022-2024
Macquarie University
2020
Mount Stromlo Observatory
2020
National Astronomical Observatory of Japan
2016
Astrobiology Center
2016
James Cook University
2014
University of Rochester
2003
Context . General circulation models of gas giant exoplanets predict equatorial jets that drive inhomogeneities in the atmospheric physical parameters across planetary surface. Aims We studied transmission spectrum hot Jupiter WASP-127 b during one transit K band with CRIRES + Methods Telluric and stellar signals were removed from data using SYSREM signal was investigated cross-correlation technique. After detecting a spectral indicative inhomogeneities, we employed Bayesian retrieval...
ABSTRACT In order to accurately determine stellar properties, knowledge of the effective temperature stars is vital. We implement Gaia and 2MASS photometry in InfraRed Flux Method apply it over 360 000 across different evolutionary stages GALAH DR3 survey. derive colour-effective relations that take into account effect metallicity surface gravity range $4000\, \rm {K}\lesssim T_{\rm {eff}}\lesssim 8000\, {K}$, from very metal-poor supersolar metallicities. The internal uncertainty these...
Context. When observing the atmospheres of transiting exoplanets using high-resolution spectroscopy, aim is to detect well-resolved spectral features with high signal-to-noise ratios (S/Ns), as possible today modern spectrographs. However, obtaining such high-quality observations comes a trade-off: lower cadence fewer, longer exposures across transit collects more photons thanks reduced overheads, enhancing S/N each observation, while higher several shorter minimises feature smearing due...
The dayside atmospheres of ultra-hot Jupiters (UHJs) are predicted to possess temperature inversion layers with extremely high temperatures at altitudes. We observed the thermal emission spectra WASP-18b and WASP-76b new CRIRES+ high-resolution spectrograph near-infrared wavelengths. Using cross-correlation technique, we detected strong CO lines in both planets, which confirms existence inversions on their hemispheres. two planets first UHJs orbiting F-type stars detected; previous...
Accurately estimating the C/O ratio of hot Jupiter atmospheres is a promising pathway towards understanding planet formation and migration, as well clouds overall atmospheric composition. The atmosphere WASP-43b has been extensively analysed using low-resolution observations with HST Spitzer, but these previous did not cover K band, which hosts prominent spectral features major carbon-bearing species such CO CH 4 . As result, ability to establish precise constraints on was limited. Moreover,...
Despite recent progress in the spectroscopic characterization of individual exoplanets, atmospheres key ultra-hot Jupiters (UHJs) still lack comprehensive investigations. These include WASP-178b, one most irradiated UHJs known to date. We observed dayside emission signal this planet with CRIRES + spectral K band. By applying cross-correlation technique and a Bayesian retrieval framework high-resolution spectra, we identified signature 12 CO ( S/N = 8.9) H 2 O 4.9), strong atmospheric thermal...
Magnetic field investigations of Sun-like stars, using Zeeman splitting non-polarised spectra, in the optical and H-band have found significantly different magnetic strengths for same cause which is currently unknown. We aim to further investigate this issue by systematically analysing ξ Boo A, a magnetically active G7 dwarf, spectral lines at wavelengths. used polarised radiative transfer accounting departures from local thermodynamic equilibrium generate synthetic spectra. To find optical,...
The ultra-hot Jupiter (UHJ) TOI-2109b marks the lower edge of equilibrium temperature gap between 3500,K and 4500,K, an unexplored thermal regime that separates KELT-9b, hottest planet yet discovered, from all other currently known gas giants. To study thermochemical structure TOI-2109b's atmosphere, we obtained high-resolution emission spectra both planetary day- nightsides with CAHA/CARMENES VLT/CRIRES^+. By applying cross-correlation technique to spectra, identified signatures Fe i...
The nearest region of massive star formation - the Scorpius-Centaurus OB2 association (Sco-Cen) is a local laboratory ideally suited to study wide range astrophysical phenomena. Precision astrometry from Gaia mission has expanded census this by an order magnitude. However, Sco-Cen's vastness and complex substructure make kinematic analysis its traditional three regions, Upper Scorpius, Centaurus-Lupus Lower Centaurus-Crux, challenging. Here we use Chronostar, Bayesian tool for age...
We aim to characterise the small-scale magnetic fields for a sample of 16 Sun-like stars and investigate capabilities newly upgraded near-infrared (NIR) instrument CRIRES$^+$ at VLT in context field studies. Our targets also had their studied optical, which allows us compare properties different spatial scales on stellar surface contrast measurements wavelengths. analyse Zeeman broadening signature six magnetically sensitive insensitive \ion{Fe}{I} lines H-band measure surface. use polarised...
The RHEA Spectrograph is a single-mode echelle spectrograph designed to be replicable and cost effective method of undertaking precision radial velocity measurements. Two versions currently exist, one located at the Australian National University in Canberra, Australia (450 - 600nm wavelength range), another Subaru Telescope Hawaii, USA (600 800 nm range). Both instruments have novel fibre feed consisting an integral field unit injecting light into 2D grid single mode fibres. This fibres...
SCExAO is the premier high-contrast imaging platform for Subaru Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K band) with stable pointing and coronagraphs extremely small inner working angles, optimized faint companions very close to host. In visible, it has several interferometric imagers which offer polarimetric spectroscopic capabilities. A recent addition RHEA spectrograph enabling spatially resolved resolution spectroscopy of surfaces giant stars, example. New...
In the current era of Gaia and large, high signal to noise stellar spectroscopic surveys, there is an unmet need for a reliable library fundamentally calibrated effective temperatures based on accurate diameters. Here we present set precision diameters sample 6 dwarf, 5 sub-giant, giant stars observed with PIONIER beam combiner at VLTI. Science targets were in least two sequences five unique calibration each visibility reduce impact bad calibrators. We use standard data reduction pipeline,...
Aims. We aim to characterise the magnetic field of eclipsing binary CU Cancri, which consists two M-dwarf components. The determination parameters this target enables comparisons with both observations similar stars and theoretical predictions strength in Cnc. therefore provides an excellent opportunity test our understanding generation fields low-mass its impact on stellar structure. Methods. used spectropolarimetric obtained ESPaDOnS at CFHT investigate properties To improve signal, we...
ABSTRACT Detailed chemical studies of F/G/K – or solar-type stars have long been routine in stellar astrophysics, enabling both Galactic chemodynamics and exoplanet demographics. However, similar understanding the chemistry M late-K dwarfs most common Galaxy has greatly hampered observationally theoretically by complex molecular their atmospheres. Here, we present a new implementation data-driven Cannon model, modelling Teff, log g, [Fe/H], [Ti/Fe] trained on low–medium resolution optical...
General circulation models of gas giant exoplanets predict equatorial jets that drive inhomogeneities across the planetary atmosphere. We studied transmission spectrum hot Jupiter WASP-127b during one transit in K band with CRIRES+. Telluric and stellar signals were removed from data using SYSREM signal was investigated cross-correlation (CCF) technique. After detecting a spectral indicative atmospheric inhomogeneities, we employed Bayesian retrieval framework 2D modelling approach tailored...
We present the results of a medium resolution optical spectroscopic survey 92 cool ($3,000 \lesssim T_{\rm eff} 4,500\,$K) southern TESS candidate planet hosts, and describe our spectral fitting methodology used to recover stellar parameters. quantify model deficiencies at predicting fluxes, while technique works well for $T_{\rm eff}$, further improvements are needed [Fe/H]. To this end, we developed an updated photometric [Fe/H] calibration isolated main sequence stars built upon sample 69...
The stars of the Milky Way carry chemical history our Galaxy in their atmospheres as they journey through its vast expanse. Like barcodes, we can extract fingerprints from high-resolution spectroscopy. fourth data release (DR4) Galactic Archaeology with HERMES (GALAH) Survey, based on a decade observations, provides abundances up to 32 elements for 917 588 that also have exquisite astrometric $Gaia$ satellite. For first time, these include life-essential nitrogen complement carbon, and...
The Replicable High-resolution Exoplanet and Asteroseismology (RHEA) spectrograph is being developed to serve as a basis for multiple copies across network of small robotic telescopes. operates at the diffraction-limit by using single-mode fiber input, resulting in compact modal-noise-free unit. optical design mainly based on off-the-shelf available components comprises near-Littrow configuration with prism cross-disperser. échelle format covers wavelength range 430-650 nm R=75,000 resolving...
RHEA is a single-mode ´echelle spectrograph designed to be replicable and cost effective method of undertaking precision radial velocity measurements. The instrument has novel fiber feed with an integral field unit injecting into grid fibers reformatted form pseudo-slit, increasing throughput enabling highspatial resolution observations when operating behind Subaru the SCExAO adaptive optics system. past 18 months have seen replacement cable constructed for address modal noise caused by...
In the past few years, there has been a resurgence in studies of space-based optical/infrared interferometry, particularly with vision to use technique discover and characterize temperate Earth-like exoplanets around solar analogs. One key technological leaps needed make such mission feasible is demonstrating that formation flying precision at level for interferometry possible. Here, we present Pyxis, ground-based demonstrator future small satellite aim demonstrate metrology interferometry....
ABSTRACT In the Gaia era, majority of stars in Solar neighbourhood have parallaxes and proper motions precisely determined while spectroscopic age indicators are still missing for a large fraction low-mass young stars. this work, we select 756 overluminous late K early M star candidates southern sky observe them over 64 nights with ANU 2.3-m Telescope at Siding Spring Observatory using Echelle (R = 24 000) Wide Field spectrographs (WiFeS, R 3000–7000). Our selection is kinematically unbiased...