#m dwarfs

[astronyms]

HAZMAT

HAbitable Zones and M dwarf Activity across Time

HAZMAT is a program to studying and modeling the atmospheres and stellar activities of Type M dwarf stars. Several terrestrial planets ("super-earths") have been discovered to be orbiting in the habitable zones of M dwarfs. However, there is still much to learn about the activity and evolution of M dwarf stars. Currently, this program is studying UV emission from M dwarfs in order to study the evolution of these stars and provide constraints on models describing the upper atmosphere of these stars. This understanding can lend a huge help in understanding the habitable zones of the stars and the possibilities for the development of life. Much of the initial work involved in HAZMAT is described in this paper.

[astronyms]

PALMS

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.

More information about the project is available here, reporting the first discovery from the survey.

[gizis-astronomy]

30 Million M Dwarfs Can't Be Wrong

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.

In the afternoon I was planning to grade quizzes, but instead I worked on my M dwarf proper motion paper. Progress by procrastination! John gave me a good reference for a color-color relationship and so I also made a nice figure for the paper.