The ESA Gaia astrometric mission and deep photometric surveys have revolutionized our knowledge of the Milky Way. There are many ongoing efforts to search these data for substructure to find evidence of individual accretion events that built up the Milky Way and its halo. One of these newly identified features, called Nyx, was announced as an accreted stellar stream traveling in the plane of the disk.

Paper PDF: 

Nix_on_Nyx.pdf

Open clusters are unique tools to study the chemical distribution of elements along the Galactic disk and its evolution with time. Thanks to precise astrometry and parallaxes from Gaia DR2, it is possible to identify the stars observed by GALAH (and by other spectroscopic surveys) that are members of these stellar associations. Once the cluster members are identified, radial velocities and chemical abundances from spectroscopy will allow us to characterise the Galactic cluster population as a function of kinematic, space, time and chemical abundances.

Paper PDF: 

GALAH_OCs_1910.pdf

Due to its proximity the Orion star forming region is often used as a proxy to study processes related to star formation and observe young stars in the environment they were born in. Orion is getting additional attention within the Gaia DR2, as distance measurements are now good enough that a three dimensional structure of the complex can be explored.

Paper PDF: 

Orion_chemistry-5.pdf

We implement Gaia and 2MASS photometry in the InfraRed Flux Method and apply it to stars across different evolutionary status in the GALAH DR3 survey. We derive colour-effective temperature relations that take into account the effect of metallicity and surface gravity over the range 3600 - 9000 K. Comparison against solar-twins, Gaia benchmark stars and the latest interferometric measurements validates the precision and accuracy of these calibrations for spectral types later than F. We assess the impact of various sources of uncertainties and provide guidelines to use our relations.

Paper PDF: 

colte.pdf

We present lithium abundances for 105 dwarf stars in the halo of the Milky Way that were accreted as part of the Gaia-Enceladus-Sausage (GES). We use these stars to investigate the ``cosmological lithium problem'' --- the observed discrepancy between the amount of lithium in old, metal-poor dwarf stars in our Galaxy, and the amount of lithium predicted to have been produced during the Big Bang. In particular, we investigate whether the formation environment of stars plays a role in the lithium abundance and scatter of the Spite Plateau.

Paper PDF: 

The_GALAH_Survey__Accreted_dwarf_stars_show_the_Lithium_Spite_Plateau-4.pdf

In this paper, we apply the spectroscopy-based stellar color regression (SCR) method proposed by Yuan et al. to perform accurate photometric calibration for the second data release of the SkyMapper Southern Survey (SMSS DR2). By using a total number of over 200,000 dwarf stars with stellar atmospheric parameters taken from the GALAH DR3 and with homogeneous accurate photometry from the Gaia DR2, strong reddening dependent zero-point (ZP) errors are detected in the photometric catalog of SMSS DR2.

Paper PDF: 

SMSS-PC.pdf

We explore the fundamental relations governing the radial and vertical velocity dispersions of stars in the Milky Way. We determine stellar age estimates from combined studies of complementary surveys including GALAH, LAMOST, APOGEE, and the NASA Kepler and K2 missions, and obtain parallax and proper motion from {\it Gaia} DR2. We find that stellar samples from these surveys, even though they target different tracer populations and employ a variety of age estimation techniques, follow the same set of fundamental relations.

Paper PDF: 

veldisp_mw.pdf

Finding a planet that's truly like our own will need a holistic, multi-disciplinary approach to solve. Whilst there are multiple criteria for what constitutes a planet like ours, we can utilise large scale galactic archaeology surveys in exoplanetary science to refine the physical properties of planet-hosting stars, whilst uncovering their chemical makeup.

Gaia DR2 has revealed numerous substructures in velocity space and in the R-Vphi plane for stars within a few kpc of the solar position. Some of these substructures trace ridges of constant energy, others trace ridges of constant angular momentum. In addition, GALAH has identified that more than 40% of local stars have super solar metallicities, and their origin in the solar neighbourhood has long been a mystery.

Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present complete results from the K2-HERMES survey, which uses the HERMES multi-object spectrograph on the Anglo-Australian Telescope to obtain R$\sim$28,000 spectra for more than 30,000 K2 stars. We present complete host-star parameters, masses, and radii for 178 K2 candidate planets from C1-C13.

Paper PDF: 

K2_Hermes_II__The_Revenge__Deluxe_MNRAS_Edition_.pdf