"A geometric calibration of the tip of the red giant branch in the Milky Way using Gaia DR3" - Dixon et al. (2023)
Alan Duffy
How do you measure distances in space? There’s no tape measure to stretch between the stars of course, but instead there are a series of techniques that work over ever increasing distances with one technique handing over to the next - the first rung on that distance ladder is Parallax (I once tried to explain this live on national Breakfast TV!) and my student Mitchell Dixon has just published a definitive study on that technique as it maps to the next rung of a special class of stars known as Tip of the Red Giant Branch (TRGB) stars which have a known (or at least calibrated!) brightness that depends on how rapidly the brighten and fade.
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