As the statistical power of galaxy weak lensing reaches per cent level precision, large, realistic, and robust simulations are required to calibrate observational systematics, especially given the increased importance of object blending as survey depths increase. To capture the coupled effects of blending in both shear and photometric redshift

A30 belongs to a class of planetary nebulae identified as "born-again", containing dense, hydrogen-poor ejecta with extreme abundance discrepancy factors (ADFs), likely associated with a central binary system. We present intermediate-dispersion spectroscopy of one such feature-the J4 equatorial knot. We confirm the apparent physical and chemical

Stellar ejecta gradually enrich the gas out of which subsequent stars form, making the least chemically enriched stellar systems direct fossils of structures formed in the early Universe 1. Although a few hundred stars with metal content below 1,000th of the solar iron content are known in the Galaxy 2-4, none of them inhabit globular clusters

Close binary evolution is widely invoked to explain the formation of axisymmetric planetary nebulae, after a brief common envelope phase. The evolution of the primary would be interrupted abruptly, its still quite massive envelope being fully ejected to form the PN, which should be more massive than a planetary nebula coming from the same star

Mid-Infrared imaging is vital for the study of a wide variety of astronomical phenomena, including evolved stars, exoplanets, and dust enshrouded processes such as star formation in galaxies. However, infrared detectors have traditionally been expensive and it is difficult to achieve the sensitivity needed to see beyond the overwhelming mid

Asteroid 162173 Ryugu is a carbonaceous asteroid that was visited by Japan's Hayabusa2 spacecraft in 2018. The formation mechanism of the "spinning-top" shape of Ryugu is a vital clue to the dynamical history of the near-Earth asteroid. In this study, we address the long-term evolution of its spin state induced by the Yarkovsky-O'Keefe-Radzievskii