Temperatures and Luminosities of M Type Dwarfs from Infrared Photometry

Citation

Veeder, Glenn John, Jr. (1974) Temperatures and Luminosities of M Type Dwarfs from Infrared Photometry. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/CRWW-Y818. https://resolver.caltech.edu/CaltechETD:etd-09052008-144355

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Broad-band infrared photometry at 1.65, 2.2 and 3.5[...] has yielded the first accurate bolometric magnitudes for a large number of M dwarfs. The intrinsic dispersion in these stars is found to be […] 0.4 magnitudes in M[…] vs. V-K and M[…] vs. R-I magnitude-color diagrams. This dispersion in the lower main sequence may be the result of differential blanketing in the UBVRI filter bands and thus there may be no such thing as a unique main sequence for the intrinsically faint M dwarfs. Scanner observations from 4500[…]to 10000[…] show severe blanketing by TiO in cool M dwarfs, but analysis shows that one parameter is sufficient to describe the blanketing in all of the UBVRI bands for all types of M dwarfs. In general, late M dwarfs seem to have lower effective temperatures than are predicted by theoretical models. Stars with hydrogen lines in emission average 0.2 to 0.3 bolometric magnitudes brighter than M dwarfs without any emission lines. The existence of flare stars with old disk space motions and also the existence of some flare stars below the main sequence complicates the picture of these stars as a pre-main sequence evolutionary stage. M dwarfs that belong to the halo population on the basis of their large space motions tend to be subluminous in M[…] vs. V-K and M[…] vs. R-I magnitude-color diagrams although there is a large scatter among the few objects of this type. The data for late dwarfs with known masses imply the empirical mass-luminosity relation: […] for stars fainter than M[…] = 7.5. In addition, the late M dwarfs are found to account for all of the "missing mass" in the plane of the galaxy.

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