Untapped: Veloce detects calcium in the atmosphere of WASP-189b

Abstract High-resolution transmission spectroscopy has become a powerful tool for detecting atomic and ionic species in the atmospheres of ultra-hot Jupiters. In this study, we demonstrate for the first time that the Australian-built Veloce spectrograph on the 3.9-m Anglo-Australian Telescope can resolve atmospheric signatures from transiting exoplanets. We observed a single transit of the ultra-hot Jupiter WASP-189b – a favourable target given its extreme irradiation and bright host star – and applied the cross-correlation technique using standardised templates. We robustly detect ionised calcium ( $\mathrm{Ca}^{+}$ ) and find evidence for hydrogen (H), sodium (Na), magnesium (Mg), neutral calcium (Ca), titanium (Ti), ionised titanium ( $\mathrm{Ti}^{+}$ ), ionised iron ( $\mathrm{Fe}^{+}$ ), neutral iron (Fe), and ionised strontium ( $\mathrm{Sr}^{+}$ ). The strongest detection was achieved in the red arm of Veloce, consistent with expectations due to the prominent $\mathrm{Ca}^{+}$ triplet at wavelengths around 850–870 nm. Our results validate Veloce’s capability for high-resolution atmospheric studies, highlighting it as an accessible, flexible facility to complement larger international telescopes. If future observations stack multiple transits, Veloce has the potential to reveal atmospheric variability, phase-dependent spectral changes, and detailed chemical compositions of highly irradiated exoplanets.