Ripe for Stars? Spitzer Spies 'Pitch Black' Cosmic Cloud
NASA/JPL-Caltech/University of Zurich
Astronomers have found cosmic clumps so dark, dense and dusty that they throw the deepest shadows ever recorded. The clumps were discovered within a huge cosmic cloud of gas and dust.
NASA/JPL-Caltech/K. Su (Univ. of Arizona)
NASA's Spitzer Space Telescope was launched 10 years ago and has since peeled back an infrared veil on the Cosmos. The mission has worked in parallel with NASA's other "Great Observatories" (Hubble and Chandra) to provide coverage of the emissions from galaxies, interstellar dust, comet tails and the solar system's planets. But some of the most striking imagery to come from the orbiting telescope has been that of nebulae. Supernova remnants, star-forming regions and planetary nebulae are some of the most iconic objects to be spotted by Spitzer. So, to celebrate a decade in space, here are Discovery News' favorite Spitzer nebulae.
First up, the Helix Nebula -- a so-called planetary nebula -- located around 700 light-years from Earth. A planetary nebula is the remnants of the death throes of a red giant star -- all that remains is a white dwarf star in the core, clouded by cometary dust.
NASA/JPL-Caltech/B. Williams (NCSU)
Spitzer will often work in tandem with other space telescopes to image a broad spectrum of light from celestial objects. Here, the supernova remnant RCW 86 is imaged by NASA's Spitzer, WISE and Chandra, and ESA's XMM-Newton.
Staring deep into the Messier 78 star-forming nebula, Spitzer sees the infrared glow of baby stars blasting cavities into the cool nebulous gas and dust.
The green-glowing infrared ring of the nebula RCW 120 is caused by tiny dust grains called polycyclic aromatic hydrocarbons -- the bubble is being shaped by the powerful stellar winds emanating from the central massive O-type star.
NASA/JPL-Caltech/J. Stauffer (SSC/Caltech)
Spitzer stares deep into the Orion nebula, imaging the infrared light generated by a star factory.
X-Ray: NASA/CXC/J.Hester (ASU); Optical: NASA/ESA/J.Hester & A.Loll (ASU); Infrared: NASA/JPL-Caltech/R.Gehrz (Univ. Minn.)
In the year 1054 A.D. a star exploded as a supernova. Today, Spitzer was helped by NASA's other "Great Observatories" (Hubble and Chandra) to image the nebula that remains. The Crab Nebula is the result; a vast cloud of gas and dust with a spinning pulsar in the center.
The Tycho supernova remnant as imaged by Spitzer (in infrared wavelengths) and Chandra (X-rays). The supernova's powerful shockwave is visible as the outer blue shell, emitting X-rays.
NASA/JPL-Caltech/E. Churchwell (University of Wisconsin - Madison)
Over 2,200 baby stars can be seen inside the bustling star-forming region RCW 49.
X-ray: NASA/CXC/Univ.Potsdam/L.Oskinova et al; Optical: NASA/STScI; Infrared: NASA/JPL-Caltech
The "Wing" of the Small Magellanic Cloud (SMC) glitters with stars and warm clouds of dust and gas. By combining observations by Spitzer, Chandra and Hubble, the complex nature of this nebulous region can be realized.
NASA’s Spitzer Space Telescope has uncovered the darkest cloud of interstellar dust and gas ever seen; it is so dense that even background infrared radiation is blocked, casting an ominous shadow across an otherwise sparkling star field.
Though the cloud may look dark and foreboding, it’s future is going to be a lot brighter. The cloud, which is about 50 light-years wide, contains enough mass for 70,000 suns and the region is ripe for the creation of potentially thousands of the most massive O-type stars, providing us with an unprecedented insight to the earliest stages of massive star formation.
“The map of the structure of the cloud and its dense cores we have made in this study reveals a lot of fine details about the massive star and star cluster formation process,” said Michael Butler, a postdoctoral researcher at the University of Zurich in Switzerland. Butler is lead author of the study that has been published in The Astrophysical Journal Letters.
Stars are often born in stellar nurseries where dense clouds of gas and dust collapse under mutual gravity. When the material reaches a certain density, fusion is sparked, forming the cores of baby stars. Clusters of young stars then blast away and consume the remaining stellar material, carving out bright star clusters. Our sun was born in such a cluster but it has since drifted far from its stellar siblings over the billions of years since its early stellar nursery days.
Although stellar evolution is fairly well understood, the creation of the most massive O-type stars is something of a mystery. O-type stars are at least 16 times the mass of our sun, the biggest can be tens to a hundred solar masses — how do they ‘bulk up’ to such extreme masses?
These stars live fast and die young as a consequence, rapidly ending their lives as powerful supernovae. Heavy elements are created in the supernova fireballs, seeding the universe with the elemental building blocks for planets and complex molecules that underlie chemical reactions and, ultimately, life. The formation and life cycle of O-type stars are therefore of the utmost importance for astronomers, hence the excitement surrounding this black cloud located approximately 16,000 light-years away that appears to have enough mass to support O-type star formation.
“In this rare kind of cloud, Spitzer has provided us with an important picture of massive star cluster formation caught in its earliest, embryonic stages,” said astronomer Jonathan Tan, of the University of Florida, Gainesville, and study co-author.
“We still do not have a settled theory or explanation of how these massive stars form,” said Tan. “Therefore, detailed measurements of the birth clouds of future massive stars, as we have recorded in this study, are important for guiding new theoretical understanding.”