I think it's just a headline writer thing. Searching for "astronomer discovers" it appears there's often an "extra" word. When it's a plurality of astronomers doing the discovering, less so.
Thinking that of Spaniards when we were behind the first steps of CRISPR, having an astronomical observatory in Tenerife, making crazy revolutionary surgery on transplants in Valencia (and so on), that's a non-issue for actual scientific environments where they are more than aware on our skills.
HN it's mainly a US site, OFC it adds information to the news by pointing that an Spaniard did it. By just putting the surname of the author of the discovery, he might seem to be from any point at the US Southern to the Patagonia in Argentina or the Iberian peninsula.