#m dwarfs

HAbitable Zones and M dwarf Activity across Time

Planets Around Low-Mass Stars

The PALMS survey is a search for giant planets in orbit around low-mass stars using the Keck-II and Subaru telescopes on Mauna Kea in Hawaii.

M dwarf stars are the most abundant stars in the Milky Way. Due to their huge numbers, we expect them to be the host of the most planets in the galaxy. However, the formation of giant planets around these stars is not very well understood. The PALMS survey is attempting to address these by performing a high contrast AO imaging survey around nearby young M dwarfs to look for young giant planets.

I had a great visit today by John Bochanski, now a postdoc at Penn State.  I'm always blown away by his sample of 30 million M dwarfs from SDSS-- let's just say our (Reid & Gizis) old 8 parsec luminosity function is a bit smaller. The new luminosity functions are still affected by systematic errors, but they've made amazing progress.  There's lots of interest in measuring metallicities of M dwarfs, partly because they're limiting progress on M dwarfs and partly because one would like to understand planet hosts.

One interesting plot he showed was the mass function. It was somewhat amusing that various authors (myself included) who bitterly fought over the slope of the mass function (if you fit a power law) or a log-normal actually had almost identical mass functions when you plot them. I suppose the lesson is derivatives are hard to measure, but in this case they're not really important.