Editing 253 Mathilde (section)

==Characteristics==
[[File:253 Mathilde side.png|thumb|left|[[Damodar (crater)|Damodar]], a 20 km-wide [[Impact crater|crater]] on Mathilde]]
[[File:253 Mathilde Flyby.gif|thumb|left|Image sequence of Mathilde during NEAR Shoemaker's flyby]]

Mathilde is very dark, with an [[albedo]] comparable to fresh [[Asphalt concrete|asphalt]],<ref>{{cite web
 |last=Pon 
 |first=Brian 
 |date=30 June 1999 
 |url=http://eetd.lbl.gov/HeatIsland/Pavements/Albedo/ 
 |title=Pavement Albedo 
 |publisher=Heat Island Group 
 |access-date=2007-08-27 
 |archive-url=https://web.archive.org/web/20070829153207/http://eetd.lbl.gov/HeatIsland/Pavements/Albedo/ 
 |archive-date=29 August 2007 
 |url-status=dead 
}}</ref> and is thought to share the same composition as CI1 or CM2 [[carbonaceous chondrite]] [[meteorite]]s, with a surface dominated by [[Silicate minerals|phyllosilicate minerals]].<ref>{{cite conference
 | author=Kelley, M. S.
 | author2=Gaffey, M. J.
 | author3=Reddy, V.
 | title=Near-IR Spectroscopy and Possible Meteorite Analogs for Asteroid (253)
 | book-title=38th Lunar and Planetary Science Conference
 | pages=2366 | publisher=Lunar & Planetary Institute
 | date=12-16 March 2007 | location=League City, Texas
 | bibcode = 2007LPI....38.2366K
 }}</ref> The asteroid has a number of extremely large [[Impact crater|crater]]s, with the individual craters being named for [[coal]] fields and basins around the world.<ref>{{cite web
 | last=Blue | first=Jennifer | date=29 August 2007
 | url=http://planetarynames.wr.usgs.gov/append6.html#Asteroids
 | title=Categories for Naming Features on Planets and Satellites
 | publisher=USGS | access-date=2007-08-29 | archive-url= https://web.archive.org/web/20070824115900/http://planetarynames.wr.usgs.gov/append6.html| archive-date= 24 August 2007 | url-status= live}}</ref> The two largest craters, Ishikari (29.3&nbsp;km) and Karoo (33.4&nbsp;km), are as wide as the asteroid's average radius.<ref name="icarus140">{{cite journal
  | author=J. Veverka | title=NEAR Encounter with Asteroid 253 Mathilde: Overview
  | journal=Icarus | date=1999 | volume=140
  | issue=1 | pages=3–16
  | bibcode=1999Icar..140....3V | doi = 10.1006/icar.1999.6120
|display-authors=etal| doi-access=free}}</ref> The impacts appear to have spalled large volumes off the asteroid, as suggested by the angular edges of the craters.<ref name="flyby">{{cite web
 | last=Williams | first=David R.
 | date=18 December 2001
 | url=http://nssdc.gsfc.nasa.gov/planetary/mission/near/near_mathilde.html
 | title=NEAR Flyby of Asteroid 253 Mathilde
 | publisher=NASA | access-date=2006-08-10 | archive-url= https://web.archive.org/web/20060818193400/http://nssdc.gsfc.nasa.gov/planetary/mission/near/near_mathilde.html| archive-date= 18 August 2006 | url-status= live}}</ref> Uniformity in brightness and colour were visible in the craters and there was no appearance of layering, so the asteroid's interior must be very homogeneous. There are indications of material movement along the downslope direction.<ref name="icarus140"/>

The density measured by NEAR Shoemaker, 1,300&nbsp;kg/m<sup>3</sup>, is less than half that of a typical carbonaceous chondrite; this may indicate that the asteroid is very loosely packed [[rubble pile]].<ref name="Yeomans 1997">{{cite journal
  | author=D. K. Yeomans | title=Estimating the mass of asteroid 253 Mathilde from tracking data during the NEAR flyby
  | journal=[[Science (journal)|Science]]
  | volume=278 | issue=5346 | date=1997 | pages=2106–9
  | pmid=9405343
  | doi=10.1126/science.278.5346.2106 |bibcode = 1997Sci...278.2106Y |display-authors=etal}}</ref> The same is true of several C-type asteroids studied by ground-based telescopes equipped with [[adaptive optics]] systems ([[45 Eugenia]], [[90 Antiope]], [[87 Sylvia]] and [[121 Hermione]]). Up to 50% of the interior volume of Mathilde consists of open space. However, the existence of a 20-km-long scarp may indicate that the asteroid does have some structural strength, so it could contain some large internal components.<ref name="aisr33"/> The low interior density is an inefficient transmitter of impact shock through the asteroid, which also helps to preserve the surface features to a high degree.<ref name="icarus140"/>

Mathilde's [[orbit]] is [[eccentricity (orbit)|eccentric]], taking it to the outer reaches of the belt. Nonetheless, the orbit lies entirely between the orbits of [[Mars]] and [[Jupiter]]; it does not cross the planetary orbits. It also has one of the slowest rotation periods of the known asteroids&mdash;most asteroids have a rotation period in the range of 2&ndash;24 hours.<ref>{{cite web
 | last=Lang
 | first=Kenneth R.
 | date=2003
 | url=http://ase.tufts.edu/cosmos/view_chapter.asp?id=15&page=3
 | title=2. Asteroids and meteorites, Size, color and spin
 | work=NASA's Cosmos
 | publisher=NASA
 | access-date=2007-08-29
 | archive-date=26 May 2024
 | archive-url=https://archive.today/20240526031853/https://www.webcitation.org/69io1CLu5?url=http://ase.tufts.edu/cosmos/view_chapter.asp%3Fid=15
 | url-status=dead
 }}</ref> Because of the slow rotation rate, NEAR Shoemaker was only able to photograph 60% of the asteroid's surface. The slow rate of rotation may be accounted for by a satellite orbiting the asteroid, but a search of the NEAR images revealed none larger than 10&nbsp;km in diameter out to 20 times the radius of Mathilde.<ref>{{cite journal
 | author=W. J. Merline | title=Search for Satellites of 253 Mathilde from Near-Earth Asteroid Rendezvous Flyby Data
 | journal=Meteoritics & Planetary Science
 | date=1998 | volume=33
 | issue=S4 | pages=A105
 | doi=10.1111/j.1945-5100.1998.tb01327.x
 | bibcode=1998M&PSA..33..105M
 |display-authors=etal| doi-access=free
 }}</ref>