Stellar observations with the Hubble Space Telescope
Pro Research Analysisby 
Searched over 200M research papers
Hubble Space Telescope Stellar Observations: Key Achievements and Insights
Exoplanet Transits and Stellar Contamination
The Hubble Space Telescope (HST) has played a crucial role in observing exoplanet transits, providing detailed spectra from the near-ultraviolet to the near-infrared. Studies of 20 exoplanets using HST’s STIS and WFC3 instruments have revealed that stellar activity can contaminate up to half of the observed exoplanet atmospheres, significantly affecting measurements of atmospheric properties such as molecular abundances and temperature. This highlights the importance of accounting for stellar contamination, especially in the optical and UV ranges where such effects are most pronounced and detectable .
Mapping Stellar Populations in Nearby Galaxies
HST’s high-resolution imaging capabilities have enabled the creation of extensive stellar catalogs. For example, the PHATTER survey mapped 22 million stars in the Triangulum Galaxy (M33) across ultraviolet to infrared wavelengths, revealing the spatial distribution of young and old stellar populations and providing the largest stellar catalog for M33 to date . Similarly, the PHANGS-HST survey has imaged 38 nearby spiral galaxies, cataloging tens of thousands of star clusters and associations, and enabling systematic studies of star formation and the cycling of gas and stars in diverse galactic environments .
Unveiling Complex Stellar Populations in Globular Clusters
HST’s multi-band photometry has uncovered the complexity of stellar populations in globular clusters. Observations of clusters like ω Centauri and NGC 2808 have revealed multiple distinct stellar populations, each with unique chemical compositions and helium abundances. These findings have transformed our understanding of globular cluster formation and evolution, showing that multiple stellar generations are common and that their origins are closely linked to the clusters’ formation history Bellini2010Milone2015Piotto2014.
Precision Measurements of Interstellar Abundances
HST’s spectrographs, such as the Goddard High-Resolution Spectrograph (GHRS), have provided precise measurements of elemental abundances in various interstellar environments. These observations have advanced knowledge of the composition of interstellar dust, the origins of high-velocity clouds, and the processes that move gas between the Galactic disk and halo. They have also established reference values for cosmological and stellar evolution studies .
Observing Massive Stellar Clusters Near the Galactic Center
HST’s NICMOS instrument has enabled the identification and study of massive young clusters near the Galactic center, such as the Arches and Quintuplet clusters. These observations have provided the first determinations of the initial mass function in this region and have shown that these clusters are among the most massive young clusters in the Galaxy .
Advancing Ultraviolet Stellar Libraries
The ULLYSES program, the largest HST UV spectroscopic survey to date, is building a comprehensive library of O and B stars in low-metallicity galaxies and accreting low-mass stars in the Milky Way. This resource is essential for understanding massive star evolution, the production of ionizing photons, and the properties of young, accreting stars, with broad implications for galaxy evolution and planet formation studies .
Overcoming Observational Challenges
HST observations in the far-ultraviolet are often affected by contamination from Earth’s airglow. Recent work has developed reliable methods to subtract airglow emission from HST/COS spectra, allowing accurate recovery of stellar emission lines and improving the study of stellar chromospheres and activity .
Conclusion
Stellar observations with the Hubble Space Telescope have revolutionized our understanding of stars, star clusters, and galaxies. From mapping millions of stars in nearby galaxies and uncovering the complexity of globular clusters, to refining measurements of exoplanet atmospheres and interstellar abundances, HST continues to provide critical data that shapes modern astrophysics. Its legacy surveys and innovative data analysis techniques ensure that HST remains at the forefront of stellar research.
Sources and full results
Most relevant research papers on this topic