Roberta (

minor planet designation A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...

: 335 Roberta) is a large

main belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

. It was discovered on 1 September 1892, by German astronomer

Anton Staus Anton Staus (5 September 1872 – 21 July 1955) was a German astronomer. As a young man, he discovered the inner main-belt asteroid 335 Roberta at Heidelberg Observatory Heidelberg (; Palatine German: ') is a city in the German state of B ...

Heidelberg Observatory Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. ...

. ''Roberta'' was the 12th asteroid that was discovered using photography, and the only asteroid discovery made by Staus. Photometric observations of this asteroid from multiple sites during 2007 gave a

light curve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

with a period of 12.054 ± 0.003 hours and a brightness variation of 0.13 ± 0.02 in

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

. This agrees with a result reported in 1992, but differs from period estimates of 8.03 hours and 4.349 reported in 1987 and 2001, respectively. Under the

SMASS classification An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiat ...

taxonomy, this asteroid is listed as a B-type; a group that combines both the Tholen B and F types. The spectrum of this object suggests the presence of

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With the ...

(Fe₃O₄), which gives it the spectrally-blue coloration that is a characteristic of this SMASS class. The spectrum of this asteroid also displays a band feature near 2.9 μm that indicate the presence of a hydrated mineral. This suggests that the asteroid has undergone significant water-based alteration. 335 Roberta was identified as one of three asteroids that were likely to be a parent body for

chondrite A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primi ...

s along with

449 Hamburga Hamburga (minor planet designation: 449 Hamburga) is a carbonaceous asteroid from the background population of the intermediate asteroid belt, approximately 75 kilometers in diameter. It was discovered by German astronomers Max Wolf and Friedric ...

and

304 Olga 3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious or cultural significance in many societie ...

.Lunar and planetary science: abstracts of papers submitted to the ... Lunar and Planetary Science Conference, Volume 27, Part 1 - Lunar and Planetary Institute, Jan 1, 1996
/ref> All three asteroids were known to have low-albedo (not reflect as much light) and be close to "meteorite producing resonances". Chrondrites are the most common type of meteor found on Earth, accounting for over 80% of all meteors. They are named for the tiny spherical silicate particles that are found inside them (those particles are called chondrules).

References

External links

Lightcurve plot of 335 Roberta
Palmer Divide Observatory, B. D. Warner (2007)
Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Roberta 000335 Discoveries by Anton Staus Named minor planets 000335 000335 18920901