Homogeneously analysing the chemical signatures of the Milky Way’s most pristine metal-poor stars is essential to reconstruct its early assembly and first-star nucleosynthetic yields. Over the next few years, WEAVE in the North and 4MOST in the South will enable high-resolution, multi-object spectroscopic follow-up of millions of Gaia stars. We present a machine learning pipeline for the...
Ultraviolet observations provide a direct view of young stellar populations associated with recent star formation in galaxies, complementing longer-wavelength observations that trace older stellar populations. The Canadian-led Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR) will provide wide-field coverage with deep imaging fields, enabling large samples of...
Carbon-enhanced metal-poor (CEMP) stars are some of the oldest and most chemically primitive stars in the Milky Way. They are defined by excess carbon and low metallicity, and further classified by neutron-capture enrichment. The origin of this unique enrichment varies between CEMP subclasses. Neutron-capture-enriched CEMP stars reflect previous extrinsic enrichment events, whereas CEMP stars...
Despite the traditional model of a Yellow Supergiant as a brief transitional phase in a star’s life before the onset of core helium burning, there is an increasing catalog of supernovae explosions that have had their progenitors identified as Yellow Supergiants from pre-explosion imaging. Notably, these supernovae are both partially-stripped and hydrogen-poor. The widespread interpretation for...
Measurements of massive star formation from Galactic and extragalactic cloud-scale observations produce conflicting results. Theory predicts that gas surface density, velocity dispersion, virial parameter, and gravitational freefall time should play a key role in setting the timescale for star formation. Milky Way observations support this prediction. In extragalactic systems, observations...
Understanding the mechanisms that drive and halt star formation requires an assessment of both the stellar and gaseous components of a large statistical sampling of galaxies. For Canadian astronomers, large optical surveys have adequately serviced the stellar components, but large samples of resolved molecular gas observations are challenging to acquire. However after 13+ years of operations,...
Using high-resolution ALMA millimeter observations, we investigate the formation of massive star clusters within the nuclear ring in NGC 3351, a nearby Milky Way analog galaxy. The dense, high-pressure conditions within nuclear rings are among the most extreme star-forming settings in the local universe, providing the ideal conditions for massive cluster formation. Nevertheless, the mechanisms...
With the advent of JWST imaging in the Local Group, young stellar objects (YSOs) are being observed in a broader range of environments than ever before, which will revolutionize our understanding of star formation if their properties can be modelled accurately. We present a new approach to characterizing YSO populations by applying the technique of population synthesis originally developed for...
Neutral atomic hydrogen is the primary raw material from which stars form in galaxies; and understanding its spatial distribution, kinematics, and thermal state across cosmic time is therefore fundamental to our comprehension of how galaxies assemble and evolve. The 21-cm hyperfine transition of neutral hydrogen is a powerful probe of cold gas in and around galaxies across cosmic time. When a...
Protostellar accretion streamers are coherent filamentary structures that channel material from envelope scales and beyond into protostellar cores. Largely found serendipitously, streamers have emerged as a potentially important yet poorly characterized mode of mass assembly in early star formation, with occurrence rates, class dependence, and environmental dependence still unconstrained....
The physical and chemical conditions present during planet formation are established during the earliest embedded Class 0/I phases of star formation. At this stage, protostellar systems are still being shaped by infall, outflows, irradiation, and chemical processing. Understanding how these processes set the initial conditions for star and planet formation requires observations that can...
The distribution of stellar masses within a globular cluster (GC) at the time of formation, referred to as the Initial Mass Function (IMF), is directly linked to the evolution of the cluster, including the rate of binary black hole (BH) mergers that produce gravitational waves. Recent studies suggest that GCs may have formed with a bottom-light IMF, meaning fewer low mass stars and more BH...
Models of the Galactic electron density are widely used to predict distances and scattering of compact radio sources, and to account for interstellar medium foregrounds in extragalactic studies. The recently updated NE2025 model (Ocker & Cordes 2026) offers improvements over its predecessor, the commonly referenced NE2001. However, its scattering predictions have yet to be tested by...
Common envelope (CE) evolution occurs when one, often more massive, star in a binary system completely engulfs a nearby companion. The companion continues its inspiral inside the shared envelope, leading to one of two outcomes: the companion merges with the primary star, or its liberated orbital energy unbinds and ejects the envelope. In the latter case, the ejection of the envelope leaves...
The nature of historical supernovae is often unknown, but supernova remnants and their environments can serve as powerful tools for probing the progenitor system. RCW 86 is a peculiar supernova remnant, thought to be associated with the historical supernova SN 185. A prevailing theory is that it was a cavity explosion, leading to questions about the nature of the progenitor system. To better...
Super-resolution microscopy is a rapidly evolving field, and analytical tools are struggling to keep up with novel imaging techniques. 'MINFLUX' (minimal fluorescence photon fluxes) is one such technique; it uses targeted emission to track molecules down to the nanometer scale. However, 'MINFLUX' outputs localizations of these molecules rather than viewing the protein superstructure directly,...
