What does this number measure?
A red supergiant known for its widely differing size estimates. The disc shown represents its diameter, twice the adopted radius of 909 nominal solar radii (1 nominal solar radius = 695 700 km). The value is a dated estimate, not an established size record. The documentary summary reports approximately 909 solar radii from the Healy et al. (2024) catalogue, using a revised Gaia distance. The 2013 estimate of 1 708 ± 192 solar radii used a greater distance. These values do not constitute a precise measurement at a single moment.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
The documentary synthesis reports about 909 solar radii based on the catalogue of Healy et al. (2024), with a revised Gaia distance. The 2013 estimate of 1 708 ± 192 solar radii used a larger distance. These values do not form a precise measurement of a single moment.
UY Scuti: an artistic illustration of a stellar photosphere. Shared generic pattern for comparing diameters; not a photograph or a reconstruction of this star. The value and its uncertainties come from the entry.