2019-11-13

exciting stars

Stars and Exoplanets Meeting at Flatiron was a delight today. Lachlan Lancaster (Princeton) showed his results on a really interesting object he found in the ESA Gaia data. He was inspired by the idea that star clusters might have central black holes, which might retain a very dense, very luminous nuclear star cluster even after the cluster disrupts. But his search of the Gaia data was so simple: Look for things that are apparently bright but low in parallax (large in distance). Duh! And what he found is a very bright “star” that is variable, shows emission lines, and is above the top of the H–R diagram! The ideas from the room ranged from extremely young star to microquasar to technosignatures (who suggested that?). And the thing is incredibly variable.

But there was lots more! I won't do everything, but I will say that Thankful Cromartie (Virginia) showed data from pulsar monitoring (as part of a pulsar-timing project for gravitational waves). She showed that she can very clearly see the Shapiro time delay in the pulses when they pass by the neutron star that is in orbit around the pulsar. This lets them measure the mass of the neutron star accurately. It is very massive! i think it must be one of the most massive neutron stars known, which, in turn, will put pressure on the equations of state. Beautiful results from beautiful data.

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