This NASA/ESA Hubble Space Telescope image features a visually stunning collection of interstellar gas and dust.
This is the nebula called RCW 7, which is located just over 5,300 light years from Earth, in the constellation of Puppis.
Nebulae are areas rich in the raw material needed to form new stars. Under the influence of gravity, parts of these molecular clouds collapse until they coalesce into very young developing stars, called protostars, which are still surrounded by rotating disks of leftover gas and dust. The protostars that form in RCW 7 are particularly massive, emitting strongly ionizing radiation and fierce stellar winds that transformed the nebula into an H II region.
H II regions are filled with hydrogen ions: HI refers to a normal hydrogen atom, while H II is hydrogen that has lost its electron and become an ion. Ultraviolet radiation from massive protostars excites the hydrogen in the nebula, causing it to emit light that gives this nebula its soft pink glow.
The Hubble data shown in this image come from the study of a particularly massive protostellar binary system called IRAS 07299-1651, which still resides in its bright cocoon of gas in the clouds that curl toward the top of the image. To expose this star and its siblings, astronomers used Hubble’s Wide Field Camera 3 in near-infrared light.
The massive protostars in this image are brightest in ultraviolet light, but they also emit a lot of infrared light. The longer wavelength of infrared light allows it to pass through much of the cloud’s gas and dust, allowing Hubble to capture it. Many of the stars that appear larger in this image are foreground stars that are not part of the nebula. Instead, they lie between the nebula and our solar system.
The creation of an H II region marks the beginning of the end for a molecular cloud like RCW 7. In just a few million years, radiation and winds from massive stars will gradually disperse the nebula’s gas, even more so as the More massive stars reach the end of their lives in supernova explosions. The new stars in this nebula will incorporate only a fraction of the nebula’s gas, the rest will spread throughout the galaxy to eventually form new molecular clouds.
