Romulus (moon)
Encyclopedia
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 discovered in February 2001 from the Keck II telescope by Michael E. Brown
and Jean-Luc Margot
. Its full designation is (87) Sylvia I Romulus; before receiving its name, it was known as S/2001 (87) 1.
The moon is named after Romulus
, the mythological founder of Rome
, one of the twins of Rhea Silvia
raised by a wolf.
87 Sylvia has a low density, which indicates that it is probably a rubble pile
formed when debris from a collision between its parent body and another asteroid re-accreted gravitationally. Therefore it is likely that both Romulus and Remus
, the second of Sylvia's moons, 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.
Romulus' orbit is expected to be quite stable − it lies far inside Sylvia's Hill sphere
(about 1/50 of Sylvia's Hill radius), but also far outside the synchronous orbit
.
From Romulus' surface, Sylvia takes up an angular region 16°×10° across, while Remus's apparent size varies between 0.62° and 0.19°.
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....
, not to be confused with the directly Sun-orbiting asteroid 10386 Romulus
10386 Romulus
10386 Romulus is an outer main-belt asteroid discovered on October 12, 1996 by V. S. Casulli at Colleverde di Guidonia.- External links :*...
. It follows an almost-circular close-to-equatorial orbit around the parent asteroid. In this respect it is similar to the other moon Remus
Remus (moon)
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....
.
Romulus was discovered in February 2001 from the Keck II telescope by Michael E. Brown
Michael E. Brown
Michael E. Brown has been a professor of planetary astronomy at the California Institute of Technology since 2003....
and Jean-Luc Margot
Jean-Luc Margot
Jean-Luc Margot is a Belgian-born astronomer and a Professor at UCLA. He specializes in planetary sciences. He was awarded the H. C. Urey Prize by the American Astronomical Society in 2004....
. Its full designation is (87) Sylvia I Romulus; before receiving its name, it was known as S/2001 (87) 1.
The moon is named after Romulus
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...
, 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 twins 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...
formed when debris from a collision between its parent body and another asteroid re-accreted gravitationally. Therefore it is likely that both Romulus and Remus
Remus (moon)
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....
, the second of Sylvia's moons, 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.
Romulus' 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 1/50 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 Romulus' surface, Sylvia takes up an angular region 16°×10° across, while Remus's apparent size varies between 0.62° and 0.19°.
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
- Adaptive Optics System Reveals New Asteroidal Satellite (SpaceDaily.com, March 2001) Includes a discovery image.
- IAUC 7590, confirming the discovery of S/2001 (87) 1
- IAUC 8582, reporting discovery of S/2004 (87) 1 and naming Romulus and Remus