[Right] - HST View of Galactic Nucleus
A NASA's Hubble Space Telescope (HST) image of a "double nucleus" in the giant spiral galaxy in Andromeda, M31. Each of the two light-peaks contains a few million densely packed stars. The brighter object is the "classic" nucleus as studied from the ground. However, HST reveals that the true center of the galaxy is really the dimmer component. One possible explanation is that the brighter cluster is the leftover remnant of a galaxy cannibalized by M31. Another idea is that the true center of the galaxy has been divided in two by deep dust absorption across the middle, creating the illusion of two peaks. This green-light image was taken with HST's Wide Field and Planetary Camera (WF/PC), in high resolution mode, on July 6, 1991. The two peaks are separated by 5 light-years. The Hubble image is 40 light-years across.
[Center] - Ground View of Galaxy Core
The nucleus is at the center of the bulge of M31, a smooth system of old stars. The bulge is apparent as the bright center of M31 in standard pictuits of the galaxy. Individual points of light are globular star clusters each containing several hundred thousand stars. This ground-based telescopic image does not resolve the double nature of the nucleus. The background of the present picture is dark only because the contrast has been adjusted to show the lull detail in the nucleus which is much brighter then the surrounding bulge.
[Left] - Ground View of Galaxy
One of the closest (neighbors to our own Milky Way galaxy, M31 (the 31st object in a catalog of non-stellar objects compiled by French astronomer Charles Messier in 1774) dominates the small group of galaxies of which our own Milky Way is a member. M31 can be seen with the naked eye as a spindle-shaped "cloud" the width of the full moon.
| About The Object | |
|---|---|
| Object Name | M31, NGC 224 |
| R.A. Position | 00h 42m 44.3s |
| Dec. Position | 41° 16' 9.4" |
| 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. |
