Galaxy population structure from proper motions

Structure of proper motions in a sunspot penumbra

Stellar Kinematics from Hipparcos Proper Motions

From Hipparcos proper motions, we have analyzed the local kinematics of the Milky Way from the young O-B5 stars, classical Cepheids, and the late-type K-M giants. Comparing the derived results, the kinematical discrepancies between each subset of stars have been analyzed, and the possible reasons for the kinematical di erences have been discussed.

Local galactic kinematics from Hipparcos proper motions

The stellar velocity field within two kiloparsecs of the solar system is investigated from the Hipparcos proper motions and parallaxes of about 20 000 single stars farther than 100 pc. The motion of the sun relative to the Local Standard of Rest and the relative systematic velocity field due to the galactic rotation are studied simultaneously for several categories of stars ranging from early t...

Macho Proper Motions From Optical/Infrared Photometry

Optical/infrared photometry can double the number of proper motion measurements of Massive Compact Objects (MACHOs) relative to single band photometry. The proper motion of a MACHO can be measured by nding the ratio q of the (known) radius of the source star to the Einstein radius of the MACHO, q = s= e. A classic method for doing this is to look for the e ect on the light curve of the nite siz...

structure of proper motions in a sunspot penumbra