This light-year-long knot of interstellar gas and dust resembles a caterpillar on its way to a feast. But the meat of the story is not only what this cosmic caterpillar eats for lunch, but also what's eating it. Harsh winds from extremely bright stars are blasting ultraviolet radiation at this "wanna-be" star and sculpting the gas and dust into its long shape.
The culprits are 65 of the hottest, brightest known stars, classified as O-type stars, located 15 light-years away from the knot, towards the right edge of the image. These stars, along with 500 less bright, but still highly luminous B-type stars make up what is called the Cygnus OB2 association. Collectively, the association is thought to have a mass more than 30,000 times that of our Sun.
The caterpillar-shaped knot, called IRAS 20324+4057, is a protostar in a very early evolutionary stage. It is still in the process of collecting material from an envelope of gas surrounding it. However, that envelope is being eroded by the radiation from Cygnus OB2. Protostars in this region should eventually become young stars with final masses about one to ten times that of our Sun, but if the eroding radiation from the nearby bright stars destroys the gas envelope before the protostars finish collecting mass, their final masses may be reduced.
Spectroscopic observations of the central star within IRAS 20324+4057 show that it is still collecting material quite heavily from its outer envelope, hoping to bulk up in mass. Only time will tell if the formed star will be a "heavy-weight" or a "light-weight" with respect to its mass.
This image of IRAS 20324+4057 is a composite of Hubble Advanced Camera for Surveys data taken in green and infrared light in 2006, and ground-based hydrogen data from the Isaac Newton Telescope in 2003, as part of the IPHAS H-alpha survey. The object lies 4,500 light-years away in the constellation Cygnus.
Credits
NASA, ESA, the Hubble Heritage Team (STScI/AURA), and IPHAS| About The Object | |
|---|---|
| Object Name | IRAS 20324+4057 |
| Object Description | Protostar in the Cygnus OB2 Association |
| R.A. Position | 20h 34m 14.11s |
| Dec. Position | 41° 8' 3.54" |
| Constellation | Cygnus |
| Distance | 4,500 light-years (1,380 parsecs) |
| About The Data | |
| Data Description | The image was created from Hubble data from proposal : R. Sahai (Jet Propulsion Laboratory), M. Morris (UCLA), C.S. Contreras (CSIC/INTA), M. Claussen (Associated Universities, Inc.), and S. Salim (Indiana University). The science teams include: N. Wright, J. Drake, M. Guarcello, and L. Hora (Harvard-Smithsonian Center for Astrophysics), J. Drew (University of Hertfordshire), R. Gutermuth (University of Massachusetts, Amherst), and K. Kraemer (Harvard-Smithsonian Center for Astrophysics/Boston College); and R. Sahai (Jet Propulsion Laboratory), M. Morris (UCLA), and M. Claussen (Associated Universities, Inc.). |
| Instrument | HST>ACS/WFC, and IPHAS>INT/WFC |
| Exposure Dates | July 22, 2006 |
| Filters | ACS/WFC: F606W (V) and F814W (I) INT/WFC: H-alpha |
| About The Image | |
| Color Info | Note: Hubble data of IRAS 20324+4057 have been combined with ground-based H-alpha observations taken in 2003 with the Isaac Newton Telescope (INT) to create the composite image. This image is a composite of separate exposures acquired by the ACS instrument and the Isaac Newton Telescope. Several filters were used to sample various wavelengths. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Cyan: H-alpha Blue: F606W (V) Orange: F814W (I) |
| Compass Image |  |
| 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. |
