Westerlund 2

 Westerlund 2

The glittering tapestry of young stars flaring to life in this NASA Hubble Space Telescope image resembles an exploding aerial shell in a fireworks display. The vibrant image is being released to celebrate Hubble’s 25 years of exploring the heavens.

The sparkling centerpiece of Hubble’s silver anniversary fireworks is a giant cluster of about 3,000 stars called Westerlund 2. The cluster resides in a raucous stellar breeding ground known as Gum 29, located 20,000 light-years away in the constellation Carina.

The stellar nursery is difficult to observe, because it is enshrouded in dust. But Hubble’s Wide Field Camera 3 peered through the dusty veil in near-infrared light, giving astronomers a clearer view of the nebula. Hubble’s sharp vision resolves the dense concentration of stars in the central cluster, which measures about 6 to 13 light-years across.

The giant star cluster is only about 2 million years old and contains some of our galaxy’s hottest, brightest, and most massive stars known. Some of the heftiest stars are carving deep cavities in the surrounding material by unleashing a torrent of ultraviolet light and gale-force stellar winds (streams of charged particles). These are etching away the enveloping hydrogen gas cloud in which the stars were born.

The image reveals a fantasy landscape of pillars, ridges, and valleys. The pillars, composed of dense gas, are resisting erosion from the fierce radiation and powerful winds. These gaseous monoliths are a few light-years tall and point to the central cluster. They may be incubators for new stars. Other dense regions surround the pillars, including reddish-brown filaments of dense gas and dust.

Besides sculpting the gaseous terrain, the brilliant stars can also help create a successive generation of offspring. When the stellar winds hit dense walls of gas, they create shocks, which may be generating a new wave of star birth along the wall of the cavity.

The red dots scattered throughout the landscape are a rich population of newly forming stars that are still wrapped in their gas-and-dust cocoons. These tiny, faint stars are between 1 million and 2 million years old and have not yet ignited the hydrogen in their cores to shine as stars. But Hubble’s near-infrared vision allows astronomers to identify these fledgling stars. The brilliant blue stars seen throughout the image are mostly foreground stars.

Because the cluster is very young, it has not had time to disperse, which occurs over time for these so-called open clusters. Astronomers can study this cluster within its star-birthing environment to gather information on how it formed.

Westerlund 2 is named for Swedish astronomer Bengt Westerlund, who discovered the grouping in the 1960s.

Constellation: Carina

Distance: 20,000 light-years (6,130 parsecs)

Instrument: Advanced Camera for Surveys and Wide Field Camera 3

Image Filters: ACS/WFC: F555W (V), F814W (I);
WFC3/IR: F125W (J)

About The Object
Object Name Westerlund 2 and Gum 29
About The Object
Object Name A name or catalog number that astronomers use to identify an astronomical object.
Object Description The type of astronomical object.
R.A. Position Right ascension – analogous to longitude – is one component of an object's position.
Dec. Position Declination – analogous to latitude – is one component of an object's position.
Constellation One of 88 recognized regions of the celestial sphere in which the object appears.
Distance The physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
Dimensions The physical size of the object or the apparent angle it subtends on the sky.
About The Data
Data Description
  • Proposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
  • Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
Instrument The science instrument used to produce the data.
Exposure Dates The date(s) that the telescope made its observations and the total exposure time.
Filters The camera filters that were used in the science observations.
About The Image
Image Credit The primary individuals and institutions responsible for the content.
Publication Date The date and time the release content became public.
Color Info A brief description of the methods used to convert telescope data into the color image being presented.
Orientation The rotation of the image on the sky with respect to the north pole of the celestial sphere.