A NASA Hubble Space Telescope (HST) image of the core of the peculiar galaxy NGC 7252 reveals a striking "mini-spiral" disk of gas and stars, and about 40 exceptionally bright and young globular star clusters. The visible light image was taken with the Wide Field and Planetary Camera (WFPC) in PC mode, on October 10, 1992. The false-color image has been subject to computer image reconstruction. The strong spiral structure is 10,000 light-years across (7 arc seconds); the entire picture is 46,000 light-years across. Hubble's resolution is so good the astronomers can measure the diameters of the clusters (0.04 arc seconds, the apparent size of a dime at a distance of 60 miles). They turn out to be about 60 light-years in diameter, the same size as globular clusters that orbit our Milky Way galaxy. The globular star clusters are concentrated near the galaxy's core. Estimated to be mostly between 50 and 500 million years old, they were apparently born following the collision of two disk-shaped galaxies about a billion years ago. The pinwheel-shaped disk of gas and young stars has an uncanny resemblance to a face-on spiral galaxy. Yet the disk is only 1/20 the diameter of the total galaxy. The disk was probably fueled by the collision. The globular clusters found in NGC 7252 are considered the progenitors of similar clusters that orbit our own Milky Way galaxy. This discovery provides some of the best evidence to date for solving more than half a century of theory and conjecture about how giant elliptical galaxies form.
Credits
Credit: : B. Whitmore (STScI), and NASA Co-investigators: : Francois Schweizer of the Carnegie Institution of Washington, Washington, D.C., and Claus Leitherer, Kirk Borne, and Carmelle Robert of STScI.| About The Object | |
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| Object Name | NGC 7252 |
| R.A. Position | 22h 20m 44.77s |
| Dec. Position | -24° 40' 41.8" |
| About The Object | |
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| 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 |
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| 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. |
