253 Mathilde

{{Infobox planet

| minorplanet=yes

| background=#D6D6D5

| name=253 Mathilde

| image=(253) mathilde crop.jpg

| image_scale =

| caption={{longitem|253 Mathilde as seen by NEAR in 1997|style=padding: 4px 0;}}

| discovery_ref=

| discoverer=J. Palisa

| discovery_site = Vienna Obs.

| discovered=12 November 1885

| mpc_name=(253) Mathilde

| alt_names=A885 VA, 1915 TN
{{mp|1949 OL|1}}

| pronounced={{IPAc-en|m|ə|ˈ|t|ɪ|l|d|ə}}

| named_after=Mathilde Loewy

| mp_category=Main belt

| epoch=31 July 2016 (JD 2457600.5)

| orbit_ref=Unless otherwise noted, parameters are per: {{cite web

| last=Yeomans | first=Donald K. | date=August 29, 2003

| url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=253

| title=253 Mathilde

| work=JPL Small-Body Database Browser

| publisher=NASA | access-date=12 May 2016 }}

| aphelion={{Convert|3.35003411|AU|Gm|abbr=on|lk=on}}

| perihelion={{Convert|1.9467702|AU|Gm|abbr=on}}

| semimajor={{Convert|2.648402147|AU|Gm|abbr=on}}

| eccentricity=0.26492652

| period=4.31 yr (1574.3 d)

| mean_anomaly=170.584348°

| inclination=6.7427122°

| asc_node=179.58936°

| arg_peri=157.39642°

| avg_speed=17.98 km/sFor semi-major axis a, orbital period T and eccentricity e, the average orbital speed is given by:

: $\begin{align}$

v_o & = \frac{2\pi a}{T}\left[1-\frac{e^2}{4}-\frac{3e^4}{64} - \dots \right] \\

& = 18.31\ \mbox{km/s} \left[ 1 - 0.0177 - 0.00008 - \cdots \right] \\

& \approx 17.98\ \mbox {km/s} \\

\end{align}\!\,

For the circumference of an ellipse, see:

{{cite book

| author=H. St̀eocker

| author2=J. Harris

| date=1998

| title=Handbook of Mathematics and Computational Science

| pages=[https://archive.org/details/handbookofmathem00harr/page/386 386]

| publisher=Springer

| isbn=0-387-94746-9

| url-access=registration

| url=https://archive.org/details/handbookofmathem00harr/page/386

}}

| dimensions=52.8 km
(66×48×46 km)

| mass={{val|1.033|0.044|e=17|u=kg}}

| density=1.3 g/cm³

| surface_grav={{Gr|1.033e-4|26.4|5}} m/s²

| escape_velocity=22.9 m/s

| rotation={{Convert|417.7|h|d|abbr=on|lk=on}}
17.406 ± 0.010 d{{cite journal

| author=Stefano Mottola | title=The slow rotation of 253 Mathilde

| journal=Planetary and Space Science

| date=1995 | volume=43 | issue=12 | pages=1609–1613

| bibcode=1995P&SS...43.1609M

| doi=10.1016/0032-0633(95)00127-1 |display-authors=etal}}
(17 d 9 h 45 min)

| spectral_type=Cb

| abs_magnitude=10.3

| albedo={{val|0.0436|0.004}}

| single_temperature=≈ 174For asteroid albedo α, semimajor axis a, solar luminosity $L_0$ , Stefan–Boltzmann constant σ and the asteroid's infrared emissivity ε (≈ 0.9), the approximate mean temperature T is given by:

: $\begin{align}$

T & = \left ( \frac{(1 - \alpha) L_0}{\epsilon \sigma 16 \pi a^2} \right )^{\frac{1}{4}} \\

& = \left ( \frac{(1 - 0.0436) (3.827 \times 10^{26}\ \mbox{W})} {0.9 (5.670 \times 10^{-8}\ \mbox{W/m}^2\mbox{K}^4) 16 \cdot 3.142 (3.959 \times 10^{11}\ \mbox{m})^2} \right )^{\frac{1}{4}} \\

& = 173.7\ \mbox{K}

\end{align}

See: {{cite book

| author=Torrence V. Johnson

| author2=Paul R. Weissman

| author3=Lucy-Ann A. McFadden

| date=2007

| title=Encyclopedia of the Solar System

| pages=[https://archive.org/details/encyclopediaofso0000unse_u6d1/page/294 294]

| publisher=Elsevier

| isbn=978-0-12-088589-3

| url=https://archive.org/details/encyclopediaofso0000unse_u6d1/page/294

}} K

| mean_motion={{Deg2DMS|0.22868000|sup=ms}} / day

| observation_arc=130.38 yr (47622 d)

| uncertainty=0

| moid={{Convert|0.939032|AU|Gm|abbr=on}}

| jupiter_moid={{Convert|2.06073|AU|Gm|abbr=on}}

| tisserand=3.331

}}

253 Mathilde is an asteroid in the intermediate asteroid belt, approximately 50 kilometers in diameter, that was discovered by Austrian astronomer Johann Palisa at Vienna Observatory on 12 November 1885. It has a relatively elliptical orbit that requires more than four years to circle the Sun. This tumbling asteroid has an unusually slow rate of rotation, requiring 17.4 days to complete a 360° revolution about its axis. It is a primitive C-type asteroid, which means the surface has a high proportion of carbon; giving it a dark surface that reflects only 4% of the light that falls on it.

Mathilde was visited by the NEAR Shoemaker spacecraft during June 1997, on its way to asteroid 433 Eros. During the short flyby, the spacecraft imaged a hemisphere of the asteroid, revealing many large craters that had gouged out depressions in the surface. It was the first carbonaceous asteroid to be explored and, until 21 Lutetia was visited in 2010, it was the largest asteroid to be visited by a spacecraft.

Observation history

File:Animation of NEAR Shoemaker trajectory.gif}}; {{legend2|Lime| 433 Eros}}; {{legend2|RoyalBlue|Earth}}; {{legend2|Cyan|253 Mathilde }}; {{legend2|Yellow|Sun;}}]]

In 1880, Johann Palisa, the director of the Austrian Naval Observatory {{Obscode|538}}, was offered a position as an assistant at the newly completed Vienna Observatory. Although the job represented a demotion for Johann, it gave him access to the new {{Convert|27|in|mm|adj=on}} refractor, the largest telescope in the world at that time. By this point Johann had already discovered 27 asteroids, and he would employ the Vienna {{Convert|27|in|mm|adj=on}} and {{Convert|12|in|mm|adj=on}} instruments to find an additional 94 asteroids before he retired.

{{cite web

| last=Raab

| first=Herbert

| date=2002

| url=http://www.astrometrica.at/Papers/Palisa.pdf

| title=Johann Palisa, the most successful visual discoverer of

| publisher=Astronomical Society of Linz

| access-date=2007-08-27

| archive-url=https://web.archive.org/web/20070928170558/http://www.astrometrica.at/Papers/Palisa.pdf

| archive-date=28 September 2007

| url-status=dead

| df=dmy-all

}}

Among his discoveries was the asteroid 253 Mathilde, found on 12 November 1885. The initial orbital elements of the asteroid were then computed by V. A. Lebeuf, another Austrian astronomer working at the Paris Observatory. The name of the asteroid was suggested by Lebeuf, after Mathilde, the wife of Moritz Loewy—who was the vice director of the observatory in Paris.{{Cite book |last=Moore |first=Sir Patrick |author-link=Patrick Moore |title=The Wandering Astronomer |date=1999 |publisher=CRC Press |isbn=0-7503-0693-9 |pages=[https://archive.org/details/wanderingastrono0000moor/page/59 59]-61 |ol=OL6899638M}}{{cite web

| author=Savage, D.

| author2=Young, L.

| author3=Diller, G.

| author4=Toulouse, A.

| date=February 1996

| url=http://www.nasa.gov/home/hqnews/presskit/1996/NEAR_Press_Kit/NEARpk.txt

| title=Near Earth Asteroid Rendezvous (NEAR) Press Kit

| publisher=NASA

| access-date=2007-08-29

| archive-date=19 March 2012

| archive-url=https://web.archive.org/web/20120319075326/http://www.nasa.gov/home/hqnews/presskit/1996/NEAR_Press_Kit/NEARpk.txt

| url-status=dead

}}

In 1995, ground-based observations determined that Mathilde is a C-type asteroid. It was also found to have an unusually long period of rotation of 418 hours.

On 27 June 1997, the NEAR Shoemaker spacecraft passed within 1,212 km of Mathilde while moving at a velocity of 9.93 km/s. This close approach allowed the spacecraft to capture over 500 images of the surface, and provided data for more accurate determinations of the asteroid's dimensions and mass (based on gravitational perturbation of the spacecraft). However, only one hemisphere of Mathilde was imaged during the fly-by.{{cite journal

| last=Cheng | first=Andrew F.

| title=Implications of the NEAR mission for internal structure of Mathilde and Eros

| journal=Advances in Space Research | date=2004 | volume=33

| issue=9 | pages=1558–1563

| bibcode=2004AdSpR..33.1558C

| doi=10.1016/S0273-1177(03)00452-6 | url=https://zenodo.org/record/997583

}} This was only the third asteroid to be imaged from a nearby distance, following 951 Gaspra and 243 Ida.

Characteristics

File:253 Mathilde side.png, a 20 km-wide crater on Mathilde]]

File:253 Mathilde Flyby.gif

Mathilde is very dark, with an albedo comparable to fresh asphalt,{{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

}} and is thought to share the same composition as CI1 or CM2 carbonaceous chondrite meteorites, with a surface dominated by phyllosilicate minerals.{{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

}} The asteroid has a number of extremely large craters, with the individual craters being named for coal fields and basins around the world.{{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}} The two largest craters, Ishikari (29.3 km) and Karoo (33.4 km), are as wide as the asteroid's average radius.{{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}} The impacts appear to have spalled large volumes off the asteroid, as suggested by the angular edges of the craters.{{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}} 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.

The density measured by NEAR Shoemaker, 1,300 kg/m³, is less than half that of a typical carbonaceous chondrite; this may indicate that the asteroid is very loosely packed rubble pile.{{cite journal

| author=D. K. Yeomans | title=Estimating the mass of asteroid 253 Mathilde from tracking data during the NEAR flyby

| 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}} 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. 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.

Mathilde's orbit is 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—most asteroids have a rotation period in the range of 2–24 hours.{{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

}} 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 km in diameter out to 20 times the radius of Mathilde.{{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

}}

References

External links

{{cite web

| author=Bowell, Ted

| author2=Koehn, Bruce

| name-list-style=amp | date=2 September 2007

| url=http://ftp.lowell.edu/pub/elgb/astorb.html

| title=The Asteroid Orbital Elements Database

| publisher=Lowell Observatory | access-date=2007-09-02 }}

{{cite web | author=Staff | date=28 August 2007 | url=http://cfa-www.harvard.edu/iau/lists/NumberedMPs.html | title=Discovery Circumstances: Numbered Minor Planets | publisher=Minor Planet Center | access-date=2007-09-02 | archive-url=https://web.archive.org/web/20080510154135/http://cfa-www.harvard.edu/iau/lists/NumberedMPs.html | archive-date=10 May 2008 | url-status=bot: unknown }}
{{cite magazine

| last=Hall | first=Alan | date=30 June 1997

| title=NEAR-ing Mathilde | magazine=Scientific American

| url=http://www.sciam.com/article.cfm?articleID=000944D0-BE16-1CF3-93F6809EC5880000

| access-date=2007-08-29 }}

[http://near.jhuapl.edu/Mathilde/mfb.gif Flyby gif] [http://near.jhuapl.edu/Mathilde/images.html parent page]
{{AstDys|253}}
{{JPL small body}}

{{Minor planets navigator |252 Clementina |number=253 |254 Augusta}}

Category:Background asteroids

Mathilde

19970627

Category:Slow rotating minor planets

Category:Cb-type asteroids (SMASS)

18851112

253 Mathilde

Observation history

Characteristics

See also

References

External links