March 4, 2014
NGC 7129, a reflection nebula in Cepheus
Image Credit: NASA/JPL-Caltech/T. Megeath (Harvard-Smithsonian CfA)
NGC 7129 (also known as the Rosebud Nebula) is a reflection nebula of about 10 light-years across, located some 3,330 light-years away from Earth in the northern constellation of Cepheus (named after the King of Aethiopia in Greek mythology).
This rosebud-shaped nebula (hence its nickname) is home to a young open cluster which contains more than 130 stars less than 1 million years old, very young by astronomical standards. These stars, that are responsible for illuminating the surrounding nebula, formed from a massive cloud of gas and dust that contains enough raw materials to create a thousand Sun-like stars..
The young stars have blown a large bubble in the molecular cloud that once surrounded them at their birth. The rosy pink hue is produced by glowing dust grains on the surface of the bubble being heated by the intense light from the embedded young stars. Upon absorbing ultraviolet and visible-light photons produced by the stars, the surrounding dust grains are heated and re-emit the energy at the longer infrared wavelengths observed by Spitzer. The reddish colors trace the distribution of molecular material thought to be rich in hydrocarbons.
Three very young stars near the center of the nebula are sending jets of supersonic gas into the cloud. The collision of these jets heats carbon monoxide molecules in the nebula. This produces the complex nebulosity that appears like a stem of a rosebud. There are also two smaller nebulae, to the left and bottom of the central “rosebud,” each containing a stellar nursery with only a few young stars
In addition, a small number of deep red crescent shapes around NGC 7129 indicate regions where new stars are forming (but are not yet visible directly). These regions are outflows of gas called Herbig Haro (HH) objects. The molecules in this gas region – H2O (water!) – are quite important (to us).
By analyzing the amount and type of (infrared) light emitted by nearly every star in the cluster within NGC 7129, scientists can find out which stars support the rings of debris, called circumstellar disks, in which planets may eventually form. Roughly half of the stars observed were found to have these disks. These observations will help astronomers determine how stellar nurseries shape the development of planetary systems similar to our own.
Astronomers believe that our own Sun may have formed billions of years ago in a cluster similar to the one in NGC 7129. Once the radiation from new cluster stars destroys the surrounding placental material, the natal gas and dust in this region will be dispersed, the stars drifting apart as the loose cluster orbits the center of the Galaxy
This four-color composite image of NGC 7129 is taken on December 12, 2004 by NASA’s Spitzer Space Telescope, with an infrared array camera that is sensitive to invisible infrared light at wavelengths that are about ten times longer than visible light. In this image, emission at 3.6 microns is depicted in blue, 4.5 microns in green, 5.8 microns in orange, and 8.0 microns in red. The image covers a region that is about one quarter the size of the full moon.