719 Albert

Orbit and classification

Albert orbits the Sun at a distance of 1.2–4.1 AU once every 4 years and 3 months (1,567 days). Its orbit has an eccentricity of 0.55 and an inclination of 12° with respect to the ecliptic. The asteroid's first observation is a precovery taken in September 1911 at Heidelberg Observatory, two weeks prior to its discovery at Vienna. The body's observation arc begins the night following its official discovery observation. Albert is also a Mars-crossing asteroid.

Close approaches

The asteroid has a minimum orbital intersection distance with Earth of 0.2030 AU, which translates into 79.1 lunar distances. On 8 September 1911, shortly before its discovery, it made its closest approach at 0.2054 AU. After another close encounter in 1941, Albert will not approach Earth to a similar distance until 2078.

Discovery

Discovered in 1911 by Johann Palisa, Albert was named after one of the Imperial Observatory in Vienna's major benefactors, Albert Salomon von Rothschild, who had died some months before. Due to inaccuracies in the asteroid's computed orbit it was subsequently lost and not recovered until 2000 by Jeffrey Larsen using data from the Spacewatch asteroid survey project. Prior to being recovered in 2000, Albert was the last lost asteroid among those assigned numbers (69230 Hermes was not numbered until 2003). The second-last lost numbered asteroid, 878 Mildred, had been recovered in 1991.

When it was rediscovered, Albert was mistakenly thought to be a new asteroid and was designated . Upon further investigation, however, it was noticed that its orbital plane matched up nicely with the last remaining lost asteroid and it was properly identified. Using the new observational data, the period was determined to be about 4.28 years instead of the 4.1 years calculated in 1911; this discrepancy was the primary reason the asteroid was lost.

Physical properties

In the SMASS classification, Albert is a common stony S-type asteroid. Others also characterized it as a stony asteroid, while a study using Sloan photometry considers it to be an X-type asteroid.

Most of what is known about 719 Albert comes from observations taken after its rediscovery. In 2001 it passed near the Earth, allowing for a series of observations at differing phase angles. During this pass its rotational period was calculated at 5.802 hours and a measured absolute magnitude of 15.43 together with an assumed albedo of 0.12 gave a diameter of 2.8 km. Another group led by R. P. Binzel measured an absolute magnitude of 15.8; they, however, used an assumed albedo of 0.15 leading to a calculated diameter of 2.4 km.

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.36 kilometers based on an absolute magnitude of 15.5.

Notes

References

References

1. (9 May 2000). "IAU Circular: IAUC 7420". IAU.
2. (2009). "Lost Asteroid".
3. Binzel, R. P.. (2002). "Asteroids III". [[University of Arizona Press]].
4. Cowen, Ron. (1 November 2002). "Astronomers Rediscover Long-Lost Asteroid". [[Science News]].
5. Binzel, R. P.. (August 2004). "Observed spectral properties of near-Earth objects: results for population distribution, source regions, and space weathering processes". [[Icarus (journal).