[RIGHT] The core of the globular cluster 47 Tucanae, as imaged by the European Space Agency's Faint Object Camera (FOC) onboard NASA's Hubble Space Telescope. The FOC resolves several hundred stars where ground- based images only yield a few dozen stars. The image reveals so-called blue straggler stars (encircled) which are exceptionally bright in ultraviolet light. HST's UV sensitivity and high resolution allow it to easily separate the blue stragglers from the red giant stars which dominate the cluster.
Blue straggler stars may evolve from "old age" back to a hotter and brighter youth through stellar collisions and mergers. This high concentration of blue stragglers towards the core of 47 Tucanae suggests they are significantly more massive than most of the cluster's stars. Some of blue stragglers could be massive because they are really double star systems. Such binary systems may influence the motions of thousands of other stars within the cluster. The FOC observations were made in ultraviolet light (2200 angstroms) on November 16, 1990 with the FOC in F/96 mode. Field of view is 11 X 11 arc seconds corresponding to a width of .75 light years, at 47 Tucanae's distance of 15,000 light years. Resolution is 0.1 arc second.
[LEFT] A ground-based CCD image of the globular cluster 47 Tucanae taken in the blue light (4400 angstroms) with the European Southern Observatory 2.2 meter telescope in Chile and a charge-coupled device. Resolution is 0.8 arcsecond, field of view 1.75 x 1.75 arcminutes, and limiting magnitude of 16.
Credits
NASA, ESA, and F. Paresce (ESA/STScI), M. Shara (STScI)Ground Image: G. Meylan (ESA/STScI)/ESO)
| About The Object | |
|---|---|
| Object Name | 47 Tucanae |
| R.A. Position | 00h 24m 5.19s |
| Dec. Position | -72° 4' 49.9" |
| 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. |
