These composite images from several observations by NASA's Hubble Space Telescope reveal a pair of newly discovered rings encircling the planet Uranus. The left composite image is made from Hubble images taken in 2003. The new dusty rings are extremely faint and required long exposures to capture their image. The background speckle pattern is noise in the image. The outermost ring (R/2003 U 1) is likely replenished by dust blasted off a newly discovered satellite called Mab, embedded in the ring and visible as a bright streak at the top of the outer ring. The new outermost ring is twice the radius of the previously known ring system around Uranus, as seen near image center. (The inner rings are much brighter, so no noise is visible in the background). Approximately halfway between the outermost ring and inner ring system is a second newly discovered ring (R/2003 U2). Only a faint segment of it appears at the 12:00 o'clock position. Because of the long exposures, the moons are smeared out and appear as arcs within the ring system.
This image also shows the positions of Uranus's other known satellites. The earliest Uranian moons discovered were primarily named for fairies and sprites taken out of English literature, and that trend continued through Voyager's discovery of Puck (from Shakespeare's A Midsummer Night's Dream) in late 1985. When the number of moons discovered by Voyager became so large, the rules were generalized so that names from traditional English literature could be used. Therfore the moons have names like Juliet, Rosalind, Ophelia, Cordelia, etc. The Hubble team actually identified the name Mab (Queen Mab the fairies' midwife in Romeo and Juliet) before their first Hubble observation, in the likelihood new moons would be discovered. Besides being a Roman god, Cupid is also a character in Shakespeare.
In the image at right, taken two years later, the rings appear more oblique because Uranus has moved along its solar orbit. The planet Uranus itself is approaching spring equinox, when the Sun will be directly shining over the planet's equator in 2007. Cloud bands and storms are becoming more pronounced in the atmosphere. A bright storm appears at northern latitudes in the 2005 images. The images were taken with the Advanced Camera for Surveys, using a clear filter.
Credits
NASA, ESA, and M. Showalter (SETI Institute)| About The Object | |
|---|---|
| Object Name | Uranus |
| Object Description | Planet |
| Distance | The semi-major axis of Uranus's orbit about the sun is 19.18 Astronomical Units (A.U.) or roughly 2.9 billion km. |
| Dimensions | Uranus (without rings) has a diameter of roughly 32,000 miles (51,000 km) at the equator. |
| About The Data | |
| Data Description | : M. Showalter (SETI Institute) and J. Lissauer (NASA Ames Research Center) |
| Instrument | HST>ACS/HRC |
| Exposure Dates | 2003 (left), and August 2005, Exposure Time: 3.7 hours (right) |
| Filters | Clear, F330W (U), F475W (g), F606W (V), F814W (I) |
| About The Image | |
| Compass Image |  |
| 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. |
