We searched for evidence of tidal stripping in the spatial structure of the dwarf satellite galaxy Carina using data from the European Space Agency satellite Gaia. The satellites of our Milky Way Galaxy are remnants of clues to its birth. Carina is intriguing because it has a more extended star formation history than other dwarf satellite galaxies of similar mass. In larger satellite galaxies the gas is retained longer, and this allows star formation to continue. The star formation history of Carina suggests that it was once more massive, and has been truncated by the gravitational forces of the Milky Way or some other satellite. Gaia data provides precise photometry, proper motions, parallaxes, and positions for over one billion stars. The proper motion and parallax data are especially intriguing, as measurements of such precision were not previously available for most of the stars. We selected potential members of Carina based on proper motion and position in the color-magnitude diagram over an area of the sky 6.5 degrees across, and used these stars to search for low-surface-density indications of tidal interaction, such as non-axisymmetric distortions of the outer regions of Carina or extended tails along the direction of orbital motion that would indicate tidally-removed stars. This project has been supported by funding from National Science Foundation grant PHY-1560077.
American Astronomical Society Meeting Abstracts #234
- Pub Date:
- June 2019