Remus (moon)
Encyclopedia
Remus is the inner and smaller moon of the main-belt asteroid
87 Sylvia
. It follows an almost-circular close-to-equatorial orbit around the parent asteroid. In this respect it is similar to the other moon Romulus
.
Remus was discovered several years after Romulus on images taken starting on August 9, 2004, and announced on August 10, 2005. It was discovered by Franck Marchis
of UC Berkeley, and Pascal Descamps, Daniel Hestroffer, and Jérôme Berthier of the Observatoire de Paris, France, using the Yepun telescope of the European Southern Observatory
(ESO) in Chile
. Marchis, the project leader, was waiting for the completion of the image acquisition programme before starting to process the data. Just as he was set to
go on vacation in March 2005, Descamps sent him a brief note entitled "87 Sylvia est triple ?" pointing out that he could see two moonlets on several images of Sylvia. The entire team then focused quickly on analysis of the data, wrote a paper, submitted an abstract to the August meeting in Rio de Janeiro and submitted a naming proposal to the IAU.
Its full designation is (87) Sylvia II Remus; before receiving its name, it was known as S/2004 (87) 1.
The moon is named after Remus
, twin of the mythological founder of Rome
, one of the children of Rhea Silvia
raised by a wolf.
87 Sylvia has a low density, which indicates that it is probably a rubble pile
asteroid formed when debris from a collision between its parent body and another asteroid re-accreted gravitationally. Thus it is likely that both Remus and Romulus are smaller rubble piles which accreted in orbit around the main body from debris of the same collision. In this case their albedo and density are expected to be similar to Sylvia's.
Remus' orbit is expected to be quite stable: it lies far inside Sylvia's Hill sphere
(about 1/100 of Sylvia's Hill radius), but also far outside the synchronous orbit
.
From Remus' surface, Sylvia appears huge, taking up an angular region roughly 30°×18° across, while Romulus' apparent size varies between 1.6° and 0.5° across.
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
87 Sylvia
87 Sylvia
87 Sylvia is one of the largest main-belt asteroids. It is a member of the Cybele group located beyond the core of the belt . Sylvia is remarkable for being the first asteroid known to possess more than one moon....
. It follows an almost-circular close-to-equatorial orbit around the parent asteroid. In this respect it is similar to the other moon Romulus
Romulus (moon)
Romulus is the outer and larger moon of the main-belt asteroid 87 Sylvia, not to be confused with the directly Sun-orbiting asteroid 10386 Romulus. It follows an almost-circular close-to-equatorial orbit around the parent asteroid. In this respect it is similar to the other moon Remus.Romulus was...
.
Remus was discovered several years after Romulus on images taken starting on August 9, 2004, and announced on August 10, 2005. It was discovered by Franck Marchis
Franck Marchis
Franck Marchis , astronomer and planetary scientist, is best known for his discovery and characterization of multiple asteroids and its study of Io volcanism.The asteroid 6639 Marchis was named in his honor on April 4, 2007....
of UC Berkeley, and Pascal Descamps, Daniel Hestroffer, and Jérôme Berthier of the Observatoire de Paris, France, using the Yepun telescope of the European Southern Observatory
European Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
(ESO) in Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
. Marchis, the project leader, was waiting for the completion of the image acquisition programme before starting to process the data. Just as he was set to
go on vacation in March 2005, Descamps sent him a brief note entitled "87 Sylvia est triple ?" pointing out that he could see two moonlets on several images of Sylvia. The entire team then focused quickly on analysis of the data, wrote a paper, submitted an abstract to the August meeting in Rio de Janeiro and submitted a naming proposal to the IAU.
Its full designation is (87) Sylvia II Remus; before receiving its name, it was known as S/2004 (87) 1.
The moon is named after Remus
Romulus and Remus
Romulus and Remus are Rome's twin founders in its traditional foundation myth, although the former is sometimes said to be the sole founder...
, twin of the mythological founder of Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
, one of the children of Rhea Silvia
Rhea Silvia
Rhea Silvia , and also known as Ilia, was the mythical mother of the twins Romulus and Remus, who founded the city of Rome...
raised by a wolf.
87 Sylvia has a low density, which indicates that it is probably a rubble pile
Rubble pile
In astronomy, rubble pile is the informal name for an object that is not a monolith, consisting instead of numerous pieces of rock that have coalesced under the influence of gravity...
asteroid formed when debris from a collision between its parent body and another asteroid re-accreted gravitationally. Thus it is likely that both Remus and Romulus are smaller rubble piles which accreted in orbit around the main body from debris of the same collision. In this case their albedo and density are expected to be similar to Sylvia's.
Remus' orbit is expected to be quite stable: it lies far inside Sylvia's Hill sphere
Hill sphere
An astronomical body's Hill sphere is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit that lies within the planet's Hill sphere. That moon would, in turn, have a Hill sphere of its own...
(about 1/100 of Sylvia's Hill radius), but also far outside the synchronous orbit
Synchronous orbit
A synchronous orbit is an orbit in which an orbiting body has a period equal to the average rotational period of the body being orbited , and in the same direction of rotation as that body.-Properties:...
.
From Remus' surface, Sylvia appears huge, taking up an angular region roughly 30°×18° across, while Romulus' apparent size varies between 1.6° and 0.5° across.
External links
- Data on (87) Sylvia from Johnston's archive (maintained by W. R. Johnston)
- Rubble-Pile Minor Planet Sylvia and Her Twins (ESO news release, August 2005) Includes images and artists impressions
- IAUC 8582, reporting discovery of S/2004 (87) 1 and naming Romulus and Remus