This image shows a small portion of a nebula called the "Cygnus Loop." Covering a region on the sky six times the diameter of the full Moon, the Cygnus Loop is actually the expanding blastwave from a stellar cataclysm - a supernova explosion - which occurred about 15,000 years ago. In this image the supernova blast wave, which is moving from left to right across the field of view, has recently hit a cloud of denser than average interstellar gas. This collision drives shock waves into the cloud that heats interstellar gas, causing it to glow. Just as the microscope revolutionized the study of the human body by revealing the workings of cells, the Hubble Space Telescope is offering astronomers an unprecedented look at fine structure within these shock fronts. Astronomers have been performing calculations of what should go on behind shock fronts for about the last 20 years, but detailed observations have not been possible until Hubble. This image was taken with Hubble's Wide Field and Planetary Camera 2 (WFPC2). The color is produced by composite of three different images. Blue shows emission from "doubly ionized" oxygen atoms (atoms that have had two electrons stripped away) produced by the heat behind the shock front. Red shows light given off by "singly ionized" sulfur atoms (sulfur atoms that are missing a single electron). This sulfur emission arises well behind the shock front, in gas that has had a chance to cool since the passage of the shock. Green shows light emitted by hydrogen atoms. Much of the hydrogen emission comes from an extremely thin zone (only several times the distance between the Sun and Earth) immediately behind the shock front itself. These thin regions appear as sharp, green, filaments in the image. This supernova remnant lies 2,500 light-years away in the constellation Cygnus the Swan.
Credits
Credit: Jeff Hester (Arizona State University) and NASA| About The Object | |
|---|---|
| Object Name | Cygnus Loop |
| R.A. Position | 20h 51m 6.0s |
| Dec. Position | 30° 40' 59.99" |
| 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. |
