Partly Cloudy, For Now

The Dark Cloud Lupus 4Lupus 4, a spider-shaped blob of gas and dust, blots out background stars like a dark cloud on a moonless night. Although dark and gloomy for now, dense pockets of material within such clouds are where new stars form and where they will later burst into radiant life. Lupus 4 is about 400 light-years away, straddling the constellations of Lupus (The Wolf) and Norma (The Carpenter’s Square).

Image Credit: ESO

A New Star Factory

Star cluster NGC 6193 and nebula NGC 6188Star cluster NGC 6193 is in the center of this image. It contains thirty or so bright stars and forms the heart of the Ara OB1 association (so named because it is in the southern constellation of Ara, the Altar). The two brightest stars are very hot giants. Together, they provide the main source of illumination for the nearby emission nebula, the Rim Nebula, or NGC 6188, visible to the right of the cluster.

The ultraviolet radiation and intense stellar wind from the stars of NGC 6193 seem to be driving the next generation of star formation in the surrounding clouds of gas and dust. As the gas and duct collapse, it forms new stars.

Image Credit: ESO


This red butterfly in space is a nebula, a giant cloud of gas and dust officially cataloged as W40. The “wings” of the butterfly are giant bubbles of gas being blown out by massive stars. The formation of those stars resulted in the destruction of the very cloud that helped create them. Stars form inside giant clouds of gas and dust as the force of gravity pulls material together into dense clumps. When a clump of matter reaches a critical density a star is born. Radiation and winds coming from the massive stars in W40 have blow  cosmic bubbles dispersing the gas and dust, breaking up smaller clumps of matter, and reducing or halting new star formation.

Image Credit: NASA


These six images are part of the Hubble Space Telescope’s Legacy ExtraGalactic UV Survey (LEGUS), the sharpest, most comprehensive ultraviolet-light survey of star-forming galaxies in the nearby universe. The survey data provide detailed information on young, massive stars and star clusters and how their environment affects their development. The six imaged galaxies include two dwarf galaxies (UGC 5340 and UGCA 281) and four large spiral galaxies (NGC 3368, NGC 3627, NGC 6744, and NGC 4258). The images are a blend of ultraviolet light and visible light from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys.
Image Credits: NASA / ESA / LEGUS

Stellar Explosions in Orion

Stellar explosions are usually associated with supernovae, the spectacular deaths of stars. New ALMA observations of the Orion Nebula provide insights into explosions at the other end of the stellar life cycle, star birth. This image shows the remains of a 500-year-old explosion from the birth of a group of massive stars; star formation can be a violent and explosive process too.

The colors in the ALMA data represent the relative Doppler shifting of the millimetre-wavelength light emitted by carbon monoxide gas. Blue data represents gas approaching at the highest speeds; the red data is from gas moving toward us more slowly.

The millimetre wave data is superimposed over optical and near-infrared images from the Gemini South and the ESO Very Large Telescope. The famous Trapezium Cluster of hot young stars appears towards the bottom of this image. The ALMA data only covers the central portion of the picture.

Image Credit: ESO

Yellow Balls

Volunteers using the web-based Milky Way Project brought star-forming features nicknamed "yellowballs" to the attention of researchers, who later showed that they are a phase of massive star formation.Infrared wavelengths of 3.6, 8.0, and 24 µm are mapped into visible colors red, green, and blue in this Spitzer Space Telescope image. The cloud of gas and dust is W33, a massive starforming complex some 13,000 light-years distant near the plane of our Milky Way Galaxy.

Amateur scientists of the web-based Milky Way Project found the features they called yellow balls as they scanned many Spitzer images and persistently asked that question of the pros. Now there is an answer. The yellow balls are  an early stage of massive star formation. They appear yellow in the false color IR images because they are overlapping regions of “red” and “green,” the colors that correspond to dust and organic molecules known as PAHs at the Spitzer detector wavelengths. Yellow balls represent the stage before newborn massive stars clear out cavities in their surrounding gas and dust.

Image Credit: NASA