A star's light yields clues about its identity which are not revealed in an image. That's why astronomers use spectrographs to decode the light. A spectrograph disperses light into its component colors, providing information on a star's rotation velocity, temperature, and surface gravity. The spectrum above compares a computer-generated spectrum of a blue straggler star with one from the observation of the blue straggler in 47 Tucanae, taken by the Hubble Space Telescope's Faint Object Spectrograph. The model spectrum predicts the shape and depth of a blue straggler's spectral lines. Based on this comparison, the Hubble telescope observation clearly matches the model.
The Hubble spectrum was taken on Oct. 27, 1995.
Credits
R. Saffer (Villanova University) and NASA| About The Object | |
|---|---|
| Object Name | 47 Tucanae, NGC 104 |
| 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. |
