Messier 102

Messier 102 – jeden z obiektów katalogu Messiera. Nie ma całkowitej pewności co do galaktyki, którą wskazuje, gdyż wpis w katalogu nie opiera się na obserwacjach autora, lecz jego przyjaciela – Pierre'a Méchaina. Najprawdopodobniej Messier dodał wpis M102 do katalogu nie sprawdziwszy uprzednio jego poprawności. Najprawdopodobniej chodziło albo o Messier 101 lub o NGC 5866.

Najbardziej prawdopodobne obiekty

Od publikacji katalogu Messiera, wiele galaktyk zostało zidentyfikowanych przez astronomów jako pasujące do opisu M102.

Messier 101

(c) ESA/Hubble, CC BY 4.0

Messier 101 (znana także jako Galaktyka Wiatraczek lub NGC 5457) to galaktyka spiralna ze słabym jądrem i bardzo rozwiniętymi ramionami w gwiazdozbiorze Wielkiej Niedźwiedzicy. W liście napisanym w 1783 do J. Bernoulliego, Pierre Méchain (który podzielił się z informacją o jej odkryciu z Messierem) napisał, że M102 była faktycznie przypadkowym powtórzeniem M101 w katalogu[1][2][3].

NGC 5866

NGC 5866 widziana przez Kosmiczny Teleskop Hubble’a. Źródło: NASA/ESA.

NGC 5866 (zwana także Galaktyką Wrzeciono) to galaktyka soczewkowata w gwiazdozbiorze Smoka. Ta galaktyka pasuje do opisów Pierre'a Méchaina w drukowanej wersji katalogu z roku 1781, i pozycji obiektu danej przez Charles’a Messiera we własnoręcznych notatkach na temat katalogu[2][3].

Inne możliwe obiekty

Oprócz M101 i NGC 5866 jest jeszcze kilka możliwych obiektów, ale są one o wiele mniej prawdopodobne.

NGC 5879, NGC 5907, NGC 5908

NGC 5879, NGC 5907 oraz NGC 5908 są galaktykami znajdującymi się blisko NGC 5866. Wszystkie one mogą być M102, jednakże są one słabsze od NGC 5866[1].

NGC 5928

NGC 5928 to galaktyka o wielkości gwiazdowej równej 14 położona pomiędzy ο Boötis i ι Serpentis. John Dreyer, w jego Notatkach i Poprawkach do New General Catalogue, sugerował, że to mogła być M102, jednakże była ona raczej zbyt słaba, by Messier czy Méchain mogli ją dostrzec[1].

Zobacz też

Przypisy

  1. a b c Glyn Jones, Kenneth: Messier's nebulae and star clusters. Cambridge (Anglia): Cambridge University Press, 1991. ISBN 0-521-37079-5.
  2. a b H. Frommert, 2006. Messier 102: Status der Identifizierung dieses Messier-Objekts (niem.). Journal für Astronomie, No. 19 (I/2006), s. 69-71 (styczeń 2006)
  3. a b H. Frommert, 10 maja 1995. Messier 102. An article on the controversy. SEDS.org

Linki zewnętrzne


Media użyte na tej stronie

Ngc5866 hst big.jpg
From original NASA press release:
This is a unique view of the disk galaxy NGC 5866 tilted nearly edge-on to our line-of-sight. Hubble's sharp vision reveals a crisp dust lane dividing the galaxy into two halves. The image highlights the galaxy's structure: a subtle, reddish bulge surrounding a bright nucleus, a blue disk of stars running parallel to the dust lane, and a transparent outer halo. NGC 5866 is a disk galaxy of type "S0" (pronounced s-zero). Viewed face on, it would look like a smooth, flat disk with little spiral structure. It remains in the spiral category because of the flatness of the main disk of stars as opposed to the more spherically rotund (or ellipsoidal) class of galaxies called ellipticals. Such S0 galaxies, with disks like spirals and large bulges like ellipticals, are called lenticular galaxies. NGC 5866 lies in the Northern constellation Draco, at a distance of 44 million light-years. It has a diameter of roughly 60,000 light-years only two-thirds the diameter of the Milky Way, although its mass is similar to our galaxy. This Hubble image of NGC 5866 is a combination of blue, green and red observations taken with the Advanced Camera for Surveys in February 2006.

And from the image's page:

This is a unique NASA Hubble Space Telescope view of the disk galaxy NGC 5866 tilted nearly edge-on to our line-of-sight.
Hubble's sharp vision reveals a crisp dust lane dividing the galaxy into two halves. The image highlights the galaxy's structure: a subtle, reddish bulge surrounding a bright nucleus, a blue disk of stars running parallel to the dust lane, and a transparent outer halo.
Some faint, wispy trails of dust can be seen meandering away from the disk of the galaxy out into the bulge and inner halo of the galaxy. The outer halo is dotted with numerous gravitationally bound clusters of nearly a million stars each, known as globular clusters. Background galaxies that are millions to billions of light-years farther away than NGC 5866 are also seen through the halo.
NGC 5866 is a disk galaxy of type "S0" (pronounced s-zero). Viewed face on, it would look like a smooth, flat disk with little spiral structure. It remains in the spiral category because of the flatness of the main disk of stars as opposed to the more spherically rotund (or ellipsoidal) class of galaxies called "ellipticals." Such S0 galaxies, with disks like spirals and large bulges like ellipticals, are called 'lenticular' galaxies.
The dust lane is slightly warped compared to the disk of starlight. This warp indicates that NGC 5866 may have undergone a gravitational tidal disturbance in the distant past, by a close encounter with another galaxy. This is plausible because it is the largest member of a small cluster known as the NGC 5866 group of galaxies. The starlight disk in NGC 5866 extends well beyond the dust disk. This means that dust and gas still in the galaxy and potentially available to form stars does not stretch nearly as far out in the disk as it did when most of these stars in the disk were formed.
The Hubble image shows that NGC 5866 shares another property with the more gas-rich spiral galaxies. Numerous filaments that reach out perpendicular to the disk punctuate the edges of the dust lane. These are short-lived on an astronomical scale, since clouds of dust and gas will lose energy to collisions among themselves and collapse to a thin, flat disk.
For spiral galaxies, the incidence of these fingers of dust correlates well with indicators of how many stars have been formed recently, as the input of energy from young massive stars moves gas and dust around to create these structures. The thinness of dust lanes in S0s has been discussed in ground-based galaxy atlases, but it took the resolution of Hubble to show that they can have their own smaller fingers and chimneys of dust.
NGC 5866 lies in the Northern constellation Draco, at a distance of 44 million light-years (13.5 Megaparsecs). It has a diameter of roughly 60,000 light-years (18,400 parsecs) only two-thirds the diameter of the Milky Way, although its mass is similar to our galaxy. This Hubble image of NGC 5866 is a combination of blue, green and red observations taken with the Advanced Camera for Surveys in November 2005.
M101 hires STScI-PRC2006-10a.jpg
(c) ESA/Hubble, CC BY 4.0
Galaktyka Messier 101, znana również jako Galaktyka Wiatraczek.