Digital Universe Guide - Hayden Planetarium
Digital Universe Guide - Hayden Planetarium
Digital Universe Guide - Hayden Planetarium
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3.3. MILKY WAY DATA GROUPS 143<br />
Not all stars are so well behaved. Some move wildly above and below the Galactic disk. Imagine<br />
how your night sky will appear under these circumstances. If we were living on a planet whose host star<br />
was high above or below the disk, we would have a magnificent, face-on view of the Galaxy. The star<br />
PM J13420-3415 is an example of such a star. At its maximum distance above the Galactic disk, the<br />
night sky on a planet similar to Earth would appear fully illuminated by the Galaxy for part of the year,<br />
and appear dark the remaining time as we look away from the Galaxy.<br />
PM J13420-3415 is only one of billions of stars that orbit the Galaxy in this fashion. The Milky Way<br />
contains a population of old, mainly dim, stars that are distributed spherically about its center.<br />
Astronomers call these halo stars. We cannot see many of these stars, let alone derive accurate<br />
distances to them. The most visible objects in the Galactic halo (halo) are the globular clusters (gc),<br />
which are dense concentrations of halo stars.<br />
Hidden Orbits For clarity, we show only 4 trajectories by default. To display the other three stars,<br />
open the mw.cf file and follow the instructions in the starorbits group. Alternatively, you can change<br />
the color of the trajectories and labels in Partiview. For example, to see the seventh star<br />
LSR J0822+1700, type cment 7 1 1 1 and textcment 7 1 1 1. The “7” represents the seventh<br />
star’s orbit, and the “1 1 1” is the red-green-blue color, which in this case is white. Frankly, it is easier to<br />
open the config file in a text editor and decide what you want to see, just scroll to the starorbits<br />
group in the mw.cf file.