#Parts of a barred spiral galaxy full#

NGC 1300, shown here, is a barred spiral galaxy. Showing great originality, astronomers call these galaxies barred spirals.įigure 26.5 Barred Spiral Galaxy. All spirals rotate, and the direction of their spin is such that the arms appear to trail much like the wake of a boat.Ībout two-thirds of the nearby spiral galaxies have boxy or peanut-shaped bars of stars running through their centers ( Figure 26.5). Spiral galaxies contain a mixture of young and old stars, just as the Milky Way does. Open star clusters can be seen in the arms of nearer spirals, and globular clusters are often visible in their halos. In galaxies that we see face on, the bright stars and emission nebulae make the arms of spirals stand out like those of a pinwheel on the fourth of July. (credit a: modification of work by Hubble Legacy Archive, NASA, ESA, and Judy Schmidt credit b: modification of work by “Jschulman555”/ Wikimedia) (b) We view this spiral galaxy, NGC 4565, almost exactly edge on, and from this angle, we can see the dust in the plane of the galaxy it appears dark because it absorbs the light from the stars in the galaxy. (a) The spiral arms of M100, shown here, are bluer than the rest of the galaxy, indicating young, high-mass stars and star-forming regions. The disks are often dusty, which is especially noticeable in those systems that we view almost edge on ( Figure 26.4).įigure 26.4 Spiral Galaxies. Bright emission nebulae and hot, young stars are present, especially in the spiral arms, showing that new star formation is still occurring. Interstellar material is usually spread throughout the disks of spiral galaxies.

They consist of a central bulge, a halo, a disk, and spiral arms. Our own Galaxy and the Andromeda galaxy are typical, large spiral galaxies (see Figure 26.2). Many smaller galaxies, in contrast, have an irregular shape. As it turns out, the biggest and most luminous galaxies come in one of two basic shapes: either they are flatter and have spiral arms, like our own Galaxy, or they appear to be elliptical (blimp- or cigar-shaped). Remember, the first step in understanding stellar spectra was simply to sort them according to appearance (see Analyzing Starlight). The first step in trying to understand a new type of object is often simply to describe it. Today, larger telescopes and electronic detectors have made this task less difficult, although observing the most distant galaxies (those that show us the universe in its earliest phases) still requires enormous effort.

#Parts of a barred spiral galaxy full#

This was a daunting task in the 1920s when obtaining a single photograph or spectrum of a galaxy could take a full night of tireless observing. Having established the existence of other galaxies, Hubble and others began to observe them more closely-noting their shapes, their contents, and as many other properties as they could measure. Explain what may cause a galaxy’s appearance to change over time.Describe the properties and features of elliptical, spiral, and irregular galaxies.By the end of this section, you will be able to: