"The star streams
that have been mapped so far are like creeks compared to the giant river of stars we predict will be observed eventually.
Such star streams
stick out from the rest of the stars in the sky as they are dense and coherent, much like contrails from airplanes easily stick out from regular clouds."
This led to a collaborative partnership between Martinez-Delgado and GaBany, who have since published 13 papers in leading journals on the discovery of tidal star streams
and rings in the outer halos of large spiral galaxies (S&T: Jan.
The star streams
are 260,000 light-years long--more than twice the length of the Milky Way.
Gill's collaboration with Kapteyn on the Cape Photographic Durchmusterung (CPD) and subsequent repeat observations had led to the discovery of two "star streams
", or preferential groups of proper motions, shared by certain stars [now known to be a reflection of halo and disc populations or old and young stars].
The new model shows a series of dense star streams
, which are similar to the distribution of stars observed in our solar neighbourhood.
Between the top of Orion and Zeta (Q Tauri, the southern horn-tip of Taurus, is a 7[degrees] sprawl of three star streams
forming the Beach Umbrella, another reminder of summer.
In a separate set of findings, astronomers looking at the outskirts of the Milky Way found two new star streams
, remnants torn from dwarf galaxies or star clusters.
Even better, the two-decade baseline will give more accurate proper motions as well, so we'll be able to predict precise stellar positions for the rest of the century-and be able to better map the Milky Way's rotation, the motions of star streams
, and members of widely dispersed moving groups (disintegrated clusters and associations whose stars were born around the same time and place).
To learn more about how galaxies form, astronomers need to determine not only how many star streams
are present but also how bright they are and how many came from now-dead satellite galaxies, comments theorist Kathryn V.
The remains of these mergers should be visible as faint arcs and loops known as tidal star streams