(253) Matilda ( Mathilde ) - the asteroid of the main belt , which belongs to the dark spectral class C. Asteroids of this class are rich in various carbon compounds that absorb most of the light incident on it and, thus, provide a very low albedo value. Matilda is one of the few asteroids, characterized by extremely low speed of rotation around the axis, the time of one revolution for it is 17.4 days. It was opened on June 27, 1884 by the Austrian astronomer Johann Paliza at the Vienna Observatory [9] and named after the wife of French astronomer Maurice Levy , who later became vice-director of the Paris Observatory . The name was suggested by the staff member of the Paris Observatory, V. A. Lebouf ( fr. VA Lebeuf ), who calculated the Matilda orbital parameters [10] .
(253) Matilda | |
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Asteroid | |
Image of an asteroid (253) Matilda | |
Discovery [1] | |
Discoverer | Johann Paliza |
Detection point | Vein |
Date of discovery | November 12, 1885 |
Alternative designations | 1949 OL 1 ; A915 TN |
Category | Main ring |
Orbital characteristics [2] | |
The Age of March 14, 2012 JD 2456000.5 | |
Eccentricity ( e ) | 0.2665678 |
Semi-axis ( a ) | 395.773 million km (2.6455804 a. E.) |
Perihelion ( q ) | 290.273 million km (1,9403539 a. E.) |
Afhelia ( Q ) | 501.274 million km (3,3508069 a. E.) |
Period of circulation ( P ) | 1571,737 days (4,303 g. ) |
Average orbital speed | 17,982 km / s |
Inclination ( i ) | 6.74296 ° |
Ascending node longitude (Ω) | 179.61903 ° |
Perihelion Argument (ω) | 157.36574 ° |
Mean Anomaly ( M ) | 164.33429 ° |
Physical characteristics [8] | |
Diameter | 52.8 km ( IRAS ) 66 × 48 × 46 km [3] [4] |
Weight | (1,033 ± 0,044) ⋅ 10 17 kg [5] |
Density | 1,300 ± 0,2 g / cm³ [6] |
Acceleration of gravity on the surface | 0,00993 m / s² |
2nd cosmic speed | 0.02285 km / s |
Rotation period | 417.7 h [7] |
Spectral class | C (Cb) |
Apparent magnitude | 15.48 m (current) |
Absolute magnitude | 10.2 m |
Albedo | 0.0436 |
Average surface temperature | 174 K (−99 ° C ) |
Current distance from the Sun | 2.451 a. e. |
Current distance from Earth | 3.178 a. e. |
In 1997, Matilda became the third asteroid that was studied directly from space using a spacecraft. The American AMC NEAR Shoemaker , heading for the Eros asteroid, took several hundred photos of the asteroid from the flight path and from which many large craters can be easily distinguished. Until 2010, when Lutetia flew near the asteroid (21) flying the Rosette spacecraft, Matilda remained the largest non-planetary body studied using a spacecraft.
Content
Research
Although the asteroid was known for more than a century , new significant studies were carried out only in 1995, during which an unusually large rotation period was determined (over 17 days) and the asteroid was assigned to the carbon spectral class C [11] .
But a real breakthrough in the study of Matilda was made a little later, on June 27, 1997 , when the American AMC NEAR Shoemaker got close to the asteroid to a distance of 1212 kilometers, flying past it at a speed of 9.93 km / s. Such a close span allowed AMC to take more than 500 photographs of the asteroid (including seven color) [12] , which, however, due to the low speed of the asteroid, allowed to map only about 60% of the surface of this object [13] . The resolution of the most qualitative of which was 180 meters per pixel [14] . The station also, on the basis of gravitational perturbations , made measurements of the magnetic field and mass of the object, and also determined the mass and density of the asteroid. Thus, Matilda became the third asteroid, after (951) Gaspra and (243) Ida , which was studied from the board of the automatic interplanetary station.
Slow rotation
Matilda is one of the slowest rotating asteroids among all the known small bodies of the Solar System , most of which have rotation periods around its axis in the range from 2 to 24 hours [15] , while the Matilda rotation period is more than 17 Earth days . Initially, scientists put forward two possible explanations for the reasons for such a low rotational speed: the release of volatile substances from the surface of the asteroid, in the opposite direction of rotation and the tidal forces of a large satellite . However, in photographs taken in 1997 by a spacecraft flying past an asteroid, there were no signs of gas emissions , nor the presence of a satellite brighter than 6-7 m , corresponding to objects 200 to 300 meters in diameter [16] .
Today it is considered that the decrease in the rotation speed of the asteroid (253) Matilda could have been caused by a collision with another relatively large asteroid with a diameter of about 3 km, which formed one of the large craters on Matilda. Upon collision, this body moved in the direction opposite to Matilda's rotation, which gave it a significant impetus upon collision, which ensured the strongest braking of the asteroid's rotational motion [17] .
Surface Structure
Matilda is a very dark and old asteroid with an average radius of about 26.4 km and a volume of 78000 km³, whose age is estimated at about 4 billion years [17] . The albedo value of the surface of this asteroid is comparable to the albedo of fresh bitumen [18] . By chemical composition, its surface is close to the composition of carbon chondrites of the first or second type (CI1 or CM2), found in meteorites found on Earth, with a predominance of silicate minerals [19] . However, the density value (1300 kg / m³), measured with the NEAR Shoemaker apparatus, is less than half the density of typical carbonaceous chondrites , which may indicate the presence of voids inside the asteroid or its high porosity , which can be up to 50% of the total volume of this body. This in turn means that the asteroid is not a monolithic body, but only a conglomerate of several small bodies covered with a thick layer of dust (a pile of rubble ) [5] . However, the detection of a large 20-km crater on the surface suggests that there are several large internal components in the asteroid [13] . Such an internal structure of the asteroid makes the propagation of shock waves through the asteroid ineffective, which makes it possible to localize the damage from collisions and ensures a high degree of preservation of the surface details [4] [6] .
A total of 23 craters were discovered on the asteroid surface studied, which were named after the largest coal deposits in the world [20] . The largest of them, crater Karoo ( eng. Karoo ), has a diameter of 33.4 kilometers and a depth of 5 - 6 km [4] . It was not possible to measure the crater depth more precisely, since most of it was in the shadows in the photographs. Crater Karoo appears to have a clearer shape and is probably the youngest of the major asteroid craters. The second largest crater is called Ishikari ( eng. Ishikari ), and has a diameter of 29.3 km. Small percussion formations can be seen on the walls of large craters, but there their density is less than the density on the inside crater surfaces. No differences in brightness and color among the craters have been identified, so the panorama of the asteroid's surface should be a fairly monotonous spectacle.
It should be noted that such a highly porous structure is characteristic of many C-class carbon asteroids, such as (45) Eugene , (87) Sylvia , (90) Antiope , (121) Hermione , it is possible that the Tungus meteorite could have a similar structure [21 ] .
See also
- List of asteroids ( 201—300 )
- Small Planet Classifications
- List of craters on the asteroid (253) Matilda
Notes
- ↑ The Wandering Astronomer. - CRC Press, 1999. - ISBN 0-7503-0693-9 .
- ↑ At known values of the big semi-axis the orbital period and eccentricity asteroid orbital speed can be determined by the following formula:
- ↑ NEAR Encounter with Asteroid 253 Mathilde (Eng.) . The appeal date is September 26, 2008. Archived February 28, 2012.
- ↑ 1 2 3 J. Veverka et al . NEAR Encounter with Asteroid 253 Mathilde: Overview (Eng.) // Icarus : journal. - Elsevier , 1999. - Vol. 140 , no. 1 . - P. 3-16 . - DOI : 10.1006 / icar.1999.6120 . - .
- ↑ 1 2 DK Yeomans et al . Estimating the mass of asteroid 253 from tracking data during the NEAR flyby (eng.) // Science : journal. - 1997. - Vol. 278 , no. 5346 . - P. 2106-2109 . - DOI : 10.1126 / science.278.5346.2106 . - . - PMID 9405343 . Archived October 1, 2007.
- 2 1 2 NEAR's Flyby of 253 Mathilde: Images of a C Asteroid . The appeal date is September 28, 2008. Archived February 28, 2012.
- ↑ Stefano Mottola et al . The slow rotation of 253 Mathilde (Eng.) // Planetary and Space Science . - Elsevier , 1995. - Vol. 43 , no. 12 - P. 1609—1613 . - DOI : 10.1016 / 0032-0633 (95) 00127-1 . - .
- ↑ At known values of the big semi-axis , light albedo α , sunshine , by Stefan-Boltzmann constant σ and infrared albedo of the asteroid ε (~ 0.9), the average temperature of the asteroid can be determined by the following formula:
- Ab Raab, Herbert Johann Palisa, the most successful visual discoverer of (English) (PDF). Astronomical Society of Linz (2002). The appeal date is August 27, 2007. Archived September 28, 2007.
- ↑ Schmadel, Lutz D. Dictionary of Minor Planet Names . - Fifth Revised and Enlarged Edition. - B. , Heidelberg, N. Y .: Springer, 2003. - P. 36. - ISBN 3-540-00238-3 .
- ↑ Near Earth Asteroid Rendezvous (NEAR) Press Kit (English) . The appeal date is September 28, 2008. Archived February 28, 2012.
- ↑ Williams, David R. NEAR Flyby of Asteroid 253 Mathilde (Eng.) . NASA (18 December 2001). Circulation date August 10, 2006. Archived August 18, 2006.
- 2 1 2 Cheng, Andrew F. Mathilde and Eros mission for the internal structure of the United Kingdom // Advances in Space Research: journal. - 2004. - Vol. 33 , no. 9 - P. 1558-1563 . - DOI : 10.1016 / S0273-1177 (03) 00452-6 . - .
- ↑ NEAR Flyby of Asteroid 253 Mathilde (NS SDC) (English) . The date of circulation is November 17, 2008. Archived February 28, 2012.
- ↑ Lang, Kenneth R. 2. Asteroids and meteorites, Size, color and spin (English) . NASA's Cosmos . NASA (2003). The appeal date was August 29, 2007. Archived August 6, 2012.
- ↑ WJ Merline et al . Search for Satellites of 253 Mathilde from Near-Earth Asteroid Rendezvous Flyby Data (Eng.) // Meteoritics & Planetary Science : journal. - 1998. - Vol. 33 , no. 1 . - P. A105 . - .
- ↑ 1 2 The Collisional History of Asteroid 253 Mathilde (English) (inaccessible link - history ) . The appeal date is September 29, 2008.
- ↑ Pon, Brian Pavement Albedo (English) (inaccessible link) . Heat Island Group (30 June 1999). The appeal date is August 27, 2007. Archived August 29, 2007.
- ↑ Kelley, MS; Gaffey, MJ; Reddy, V. (March 12–16, 2007). " Near-IR Spectroscopy and Possible Meteorite Analogs for Asteroid (253) ". 38th Lunar and Planetary Science Conference : 2366, League City, Texas: Lunar & Planetary Institute. Checked on 2007-08-29 .
- ↑ Blue, Jennifer Categories for Naming Features on Planets and Satellites (English) . USGS (29 August 2007). The appeal date was August 29, 2007. Archived August 24, 2007.
- ↑ BBC News. Tunguska meteorite: no more secrets? The appeal date is September 28, 2008. Archived February 28, 2012.
Links
- NASA JPL Database on Small Bodies of the Solar System (253) (eng.)
- MPC Database on Small Bodies of the Solar System (253) (eng.)
- NEAR Flyby of Asteroid 253 Mathilde. (eng.)
- Minor Planet Center. Discovery Circumstances: Numbered Minor Planets. (eng.)
- Astronomy Picture of the Day. Lutetia: The Largest Asteroid Yet Visited (Eng.) (July 26, 2010). The appeal date is February 16, 2014.