Extremely intense radiation from newly born, ultra-bright stars has blown a glowing spherical bubble in the nebula N83B, also known as NGC 1748. A new NASA Hubble Space Telescope image has helped to decipher the complex interplay of gas and radiation of a star-forming region in a nearby galaxy. The image graphically illustrates just how these massive stars sculpt their environment by generating powerful winds that alter the shape of the parent gaseous nebula. These processes are also seen in our Milky Way in regions like the Orion Nebula.
The Hubble telescope is famous for its contribution to our knowledge about star formation in very distant galaxies. Although most of the stars in the Universe were born several billions of years ago, when the Universe was young, star formation still continues today. This new Hubble image shows a very compact star-forming region in a small part of one of our neighboring galaxies - the Large Magellanic Cloud. This galaxy lies only 165,000 light-years from our Milky Way and can easily be seen with the naked eye from the Southern Hemisphere.
Young, massive, ultra-bright stars are seen here just as they are born and emerge from the shelter of their pre-natal molecular cloud. Catching these hefty stars at their birthplace is not as easy as it may seem. Their high mass means that the young stars evolve very rapidly and are hard to find at this critical stage. Furthermore, they spend a good fraction of their youth hidden from view, shrouded by large quantities of dust in a molecular cloud. The only chance is to observe them just as they start to emerge from their cocoon - and then only with very high-resolution telescopes.
Astronomers from France, the U.S., and Germany have used Hubble to study the fascinating interplay between gas, dust, and radiation from the newly born stars in this nebula. Its peculiar and turbulent structure has been revealed for the first time. This high-resolution study has also uncovered several individual stars that are responsible for lighting up this cloud of gas.
The apparently innocuous-looking star at the very center of the nebula, just below the brightest region, is actually about 30 times more massive and almost 200,000 times brighter than our Sun. The intense light and powerful stellar "winds" from this ultra-bright star have cleared away the surrounding gas to form a large cavity. The bubble is approximately 25 light-years in diameter - about the same size as the famous star-forming Orion Nebula. The Orion Nebula is sculpted by intense radiation from newly born stars in the same way as N83B. Astronomers estimate that the spherical void in N83B must have been carved out of the nebula very recently - in astronomical terms - maybe as little as 30,000 years ago.
The hottest star in N83B is 45 times more massive than the Sun and is embedded in the brightest region in the nebula. This bright region, situated just above the center, is only about 2 light-years across. The region's small size and its intense glow are telltale signs of a very young, massive star. This star is the youngest newcomer to this part of the Large Magellanic Cloud. The Hubble image shows a bright arc structure just below the luminous star. This impressive ridge may have been created in the glowing gas by the hot star's powerful wind.
Measurements of the age of this star and neighboring stars in the nebula show that they are younger than the nebula's central star. Their formation may have been "triggered" by the violent wind from the central star. This "chain-reaction" of stellar births seems to be common in the Universe. About 20 young and luminous stars have been identified in the region, but it may well be that many more massive stars remain undetected in other areas of the Large Magellanic Cloud, hidden by dust in small clusters like N83B.
To the right of the glowing N83B is a much larger diffuse nebula, known as DEM22d, which is partly obscured by an extended lane of dust and gas.
This image is composed of three narrow-band-filter images obtained with Hubble's Wide Field Planetary Camera 2 in May 2000. The colors are red (ionized hydrogen, H-alpha), green (ionized oxygen), and blue (ionized hydrogen, H-beta). The blue corresponds to the warmest regions, the red to the coldest. The full image is 66 x 133 arc-seconds, which corresponds to 55 x 108 light-years at the distance of the Large Magellanic Cloud.
Credits
NASA, ESA, Mohammad Heydari-Malayeri (Observatoire de Paris, France)| About The Object | |
|---|---|
| Object Name | N83B, NGC 1748 |
| Object Description | Star-Forming Region in the Large Magallenic Cloud (LMC) |
| R.A. Position | 04h 54m 25.2s |
| Dec. Position | -69° 10' 59.99" |
| Constellation | Dorado |
| Distance | About 51 kpc (165,000 light-years) |
| Dimensions | The bubble is approximately 25 light-years in diameter. |
| About The Data | |
| Data Description | Principal Astronomers: M. Heydari-Malayeri (Observatoire de Paris, France), V. Charmandaris (Cornell University, United States), L. Deharveng (Observatoire de Marseille, France), M.R. Rosa (ST-ECF, Germany), D. Schaerer (Observatoire Midi-Pyre'ne'es, France), H. Zinnecker (Astrophysikalisches Institut Potsdam, Germany) |
| Instrument | HST>WFPC2 |
| Exposure Dates | February 7, 2000; May 21, 2000, Exposure Time: ~ 1 hour |
| Filters | F656N (Ha), F502N ([O III]), F487N (Hb) |
| 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 |
|
| 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. |
