NASA's Hubble Space Telescope snapped pictures of a double system of icy bodies in the Kuiper Belt. This composite picture shows the apparent orbit of one member of the pair. In reality, the objects, called 1998 WW31, revolve around a common center of gravity, like a pair of waltzing skaters. This picture shows the motion of one member of the duo [the six faint blobs] relative to the other [the large white blob]. The blue oval represents the orbital path. Astronomers assembled this picture from six separate exposures, taken from July to September 2001, December 2001, and January to February 2002.
Astronomers used the Hubble telescope to study the orbit of this binary system. They then used that information to determine other characteristics of the duo, such as their total mass, and their orbital period (the time it takes them to orbit each other).
Credits
NASA and C. Veillet (Canada-France-Hawaii Telescope)| About The Object | |
|---|---|
| Object Name | 1998 WW31 |
| Object Description | Kuiper Belt Object |
| Distance | Distance from the Sun: The binary object has a semi-major axis of ~ 45 astronomical units (6.7 x 109 km or 4.2 x 109 miles). Distance from Earth: During the time of the HST observations (July 2001- February 2002) the binary system was ~ 46.5 astronomical units from the Earth. Distance between objects: The semi-major axis of the components of the binary system is ~ 22,300 km (13,900 miles). The eccentricity of the orbit makes this physical distance vary between 4,000 and 40,000 km (2,500 and 25,000 miles). Orbit: The binary objects have an orbital period about each other of ~ 570 days. The system orbits the Sun every 300 years. |
| Dimensions | The HST image is roughly 7 arcseconds (roughly 226,000 km or 141,000 miles) across. The binary objects are estimated to be roughly 150 km and 130 km in diameter. Total Mass: The binary objects have a total mass of 0.00021 that of Pluto. |
| About The Data | |
| Data Description | Principal Astronomers: C. Veillet (CFHT), J. W. Parker (SwRI), I. P. Griffin (STScI), B. G. Marsden (SAO), A. Doressoundiram, (Observatoire de Paris), D. J. Tholen (Univ. of Hawaii), M.W. Buie (Lowell Obs.), M. J. Holman (SAO) Summary of All Data KPNO 4-m telescope: November 1998; January and November 1999; November 2000 CFH 3.6-m telescope: January and December 2000; J HST WFPC2: July 2001- February 2002 |
| Instrument | HST>WFPC2 |
| Exposure Dates | July to September 2001, December 2001, and January to February 2002 |
| Filters | F555W (V), F675W (R), F814W (I) |
| 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. |
