67P/Tjurjumov-Gerasimenko
| 67P/Tjurjumov-Gerasimenko | |
|---|---|
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| Opdaget | |
20. september 1969, af Klim Ivanovitj Tjurjumov og Svetlana Ivanova Gerasimenko | |
| Kredsløb om Solen | |
| Halve storakse | 8,560 108 km |
| Halve lilleakse | 1,933 108 km |
| Excentricitet | 0,6315 |
| Banehældning | 7,1205° |
| Fysiske egenskaber | |
| Diameter | 4 km |
| Rumfang | ca. 25 km³ |
| Masse | (1.0±0.1)×10×1013 kg |
| Massefylde | ca. 400 kg/m³ |
| Temperatur v. ovfl. | Min. -68 °C Maks. -43 °C |
Tjurjumov-Gerasimenko[1] (Чурюмова-Герасименко) (også kaldet 67P/Tjurjumov-Gerasimenko) er en komet i en bane om Solen med en omløbstid på 6,45 år og en rotationsperiode på 12,4 timer. Kometen havde sit sidste perihelium (nærmeste afstand til Solen) den 13. august 2015. Kometen måler ca. 4 km x 3,5 km x 3,5 km.
Tjurjumov-Gerasimenko var målet for ESA's Rosetta-mission, der begyndte den 2. marts 2004. Rosetta nåede kometen i august 2014, og den 12. november 2014 landede Rosettas landingsmodul, Philae, på kometen. Landingen var den første kontrollerede landing med et rumfartøj på en komet. Rosetta har optaget en lang række billeder af 67P/Tjurjumov-Gerasimenko på vej mod landsætningen. 67P/Tjurjumov-Gerasimenko er blevet den første komet, der er underkastet videnskabelige nærundersøgelser[2][3] og filmet i nærbillede.[4][5] På grund af Tjurjumov-Gerasimenkos dobbeltstruktur er det blevet foreslået at den er en binær komet med to forbundne kerner[6]. Tjurjumov-Gerasimenko har en lille måne.[7]
Opdagelse
Kometen blev opdaget i 1969 af Klim Ivanovich Tjurjumov fra Kijevs astronomiske observatorium,[8] der gennemgik fotografier, der var taget af Svetlana Gerasimenko den 11. september 1969 ved det astrofysiske institut i Almaty med henblik på at lede efter den periodiske komet 32P/Comas Solà. Tjurjumov fandt et kometlignende objekt i billedets periferi, men antog, at det var Comas Solà.[9]
Efter at være hjemvendt til Kijev undersøgte Tjurjumov de fotografiske plader mere grundigt. Den 22. oktober konstaterede han, at objektet ikke kunne være Comas Solà, da det befandt sig 1,8 grader fra den forventede position. Yderligere analyser viste, at der var et svagt billede af Comas Solà, der hvor Comas Solà var forventet at befinde sig på fotografiet, hvorved det var påvist, at det nye objekt måtte være en nyopdaget komet.[9]
I overensstemmelse med sædvanlig praksis er kometen opkaldt efter dens to opdagere. Tjurjumov-Gerasimenko er den 67. periodiske komet, man kender banen for, hvorfor kometen også benævnes 67P/Tjurjumov-Gerasimenko.
Galleri
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0Tjurjumov-Gerasimenko set fra Rosetta den 18. august 2014 i 88 km afstand
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0Tjurjumov-Gerasimenko set i 28 km afstand fra
Rosetta-rumsonden den 24. september 2014
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0Set fra Rosetta i 9,8 km afstand den 18. oktober
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0Set fra Rosetta den 30. oktober 2014 i 26,8 km afstand
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.02. november, 33,4 km fra overfladen
Observeret fra Jorden den 11. august ved hjælp af ESO's Very Large Telescope i Chile
Noter
- ^ Europæisk rumfartøj suste forbi Mars Arkiveret 27. februar 2007 hos Wayback Machine hentet d. 9. nov. 2009
- ^ "Catching a comet. Science Special Issue, 23. jan 2015". Arkiveret fra originalen 15. marts 2015. Hentet 11. marts 2015.
- ^ "Nyt fra Rosetta: Kometen er kulsort, støvet og fuld af organisk materiale. Videnskab.dk". Arkiveret fra originalen 26. januar 2015. Hentet 11. marts 2015.
- ^ "Rosettas første manøvre gik efter planen. Videnskab.dk". Arkiveret fra originalen 12. august 2014. Hentet 9. august 2014.
- ^ "European Spacecraft Pulls Alongside Comet After 10 Years and Four Billion Miles. New York Times, august 2014". Arkiveret fra originalen 11. august 2014. Hentet 9. august 2014.
- ^ Planetary Society (15. juli 2014). "Churyumov-Gerasimenko is a contact binary!". Arkiveret fra originalen 20. juli 2014. Hentet 21. juli 2014.
- ^ https://www.iflscience.com/space/comet-67p-has-its-own-tiny-churymoon/ Arkiveret 16. august 2019 hos Wayback Machine Comet 67P Has Its Own Tiny "Churymoon". IFLScience 2019
- ^ "Klim Ivanovich Churyumov". International Astronomical Union. Arkiveret fra originalen 10. april 2016. Hentet 8. august 2014.
- ^ a b Kronk, Gary W.; et al. (2010). "67P/1969 R1 (Churyumov-Gerasimenko)". Cometography: A Catalog of Comets; Volume 5: 1960-1982. Cambridge University Press. s. 241-245. ISBN 052187226X. Arkiveret fra originalen 30. december 2016. Hentet 4. november 2014.
Eksterne links
- Rosetta's target: Comet 67P/Churyumov-Gerasimenko - fra ESAs website (www.sci.esa.int) Arkiveret 21. august 2019 hos Wayback Machine
- NASA's hjemmeside om Rosetta-missionen Arkiveret 30. oktober 2014 hos Wayback Machine
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(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
Mosaic of four images taken by Rosetta's navigation camera (NAVCAM) on 24 September 2014 at 28.5 km from the centre of comet 67P/Churyumov-Gerasimenko.
The images used for this mosaic were taken in sequence as a 2×2 raster over a period of about 20 minutes, meaning that there is some motion of the spacecraft and rotation of the comet between the images. The mosaicking programme that was used (Microsoft ICE) seems to have done a nice job of stitching the images together, but if you refer to the four separate images you will see some differences in illumination and shadows. The four individual full-frame images are available as related images in the right-hand menu. Note this mosaic has been rotated by 180 degrees and cropped to remove most of the black space around the comet. The images were background subtracted to remove some striping and fixed noise patterns.
Read more about this image in the blog : CometWatch 21 & 24 September.
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
Rosetta navigation camera image taken on 18 August 2014 at about 84 km from comet 67P/Churyumov-Gerasimenko. The comet nucleus is about 4 km across.
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
Mosaic of four images taken by Rosetta's navigation camera (NAVCAM) on 2 November 2014 at 33.4 km from the centre of comet 67P/Churyumov-Gerasimenko – about 31.4 km from the surface. The image scale is 2.68 m/pixel.
The images used for this mosaic were taken in sequence as a 2×2 raster over a short period af about twenty minutes, meaning that there is some motion of the spacecraft and rotation of the comet between the images. The images have been cleaned to remove the more obvious bad 'pixel pairs' and cosmic ray artefacts. The mosaic has been slightly rotated and cropped and covers 4.1 x 4.1 km: some contrast enhancement has been applied.
The four individual images making up the mosaic are available via the blog : CometWatch – 2 November
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
This four-image NAVCAM mosaic shows Philae’s landing site as Rosetta departed its 10 km orbit last week in order to prepare for the deployment of Philae on 12 November 2014. The images comprising this montage were taken on 30 October, when the spacecraft was 26.8 km from the centre of the comet. The image resolution at this distance is 2.27 m/pixel, and the mosaic covers 4.0 x 3.7 km. The four individual images making up the mosaic are available via the blog : CometWatch 30 October – Farewell J
Forfatter/Opretter: Colin Snodgrass/ESO/ESA, Licens: CC BY 4.0
The bright, hazy smudge at the centre of this image is a comet known as 67P/Churyumov-Gerasimenko, or 67P/C-G for short. This is not just any comet; it is the target for ESA’s Rosetta spacecraft, which is currently deep within the comet’s coma and less than 100 kilometres from its nucleus [1]. With Rosetta so close to the comet, the only way to view the whole of 67P/C-G now is to observe it from the ground.
This image was taken on 11 August 2014 using one of the 8-metre telescopes of ESO’s Very Large Telescope (VLT) in Chile. It was composed by superimposing 40 individual exposures, each lasting 50 seconds, and removing background stars, to obtain the optimal view of the comet. Rosetta is contained within the central pixel of this image, and is too small to resolve.
The VLT is made up of four individual Unit Telescopes that can work together or individually to study the night sky. These observations used the FORS2 (FOcal Reducer and low dispersion Spectrograph 2) instrument on Unit Telescope 1, otherwise known as Antu, which is the indigenous Chilean Mapuche term for the Sun.
FORS2 can be used in various ways, but for the Rosetta campaign astronomers use it to image the comet and determine its brightness, size and shape; and also to analyse the coma’s composition.
Although 67P/C-G is faint in this image, it is clearly active, with a dusty coma extending some 19 000 kilometres out from the nucleus. This coma is asymmetric as the dust is being swept away from the Sun — which is located beyond the lower right corner of the image — and is beginning to form a characteristic cometary tail.
This VLT image is part of an ongoing collaboration between ESA and ESO to observe 67P/C-G from the ground while Rosetta is performing measurements at the comet. On average, the VLT obtains images of the comet every second night. These short exposures are used to monitor the comet's activity by studying how its brightness changes. The results are reported back to the Rosetta project and provide part of the information for planning how to orbit around it.
Notes
[1] Rosetta reached a distance of 100 kilometres from 67P/C-G’s nucleus on 6 August 2014, and has been moving closer to the comet since then.
(c) ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0
Full-frame Rosetta navigation camera (NAVCAM) image taken on 18 October 2014 at 9.8 km from the centre of comet 67P/Churyumov–Gerasimenko. NAVCAM image sequences are now being taken as small 2×2 rasters and only part of the comet is seen in each of the four images. A montage of all four images from this sequence is available here.
Forfatter/Opretter: Justin Cowart, Licens: CC BY 2.0
Approximate true color image of comet 67P taken by the Rosetta spacecraft's OSIRIS Narrow Angle Camera on March 17, 2015. This image is a four frame mosaic, with each color frame imaged through VIS_BLUE, VIS_GREEN, and VIS_RED filters. At the time this image was taken, Rosetta was located roughly 82 km (51 mi) from the comet's centre.
Image Credit: ESA / Rosetta / MPS for OSIRIS Team (MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA) / Justin Cowart