பயனர்:TNSE MANI VNR/மணல்தொட்டி

Pinwheel Galaxy
M101 hires STScI-PRC2006-10a.jpg
கண்டறிந்த தகவல்கள் (J2000 ஊழி)
விண்மீன் குழுUrsa Major
வல எழுச்சிக்கோணம்14h 03m 12.6s
பக்கச்சாய்வு+54° 20′ 57″
தூரம்20.9 ± 1.8 Mly (6.4 ± 0.5 Mpc)
தோற்றப் பரிமாணங்கள் (V)28′.8 × 26′.9
தோற்றப் பருமன் (V)7.86
ஏனைய பெயர்கள்
Messier 101, M101, NGC 5457, UGC 8981, PGC 50063, Arp 26
இவற்றையும் பார்க்க: பேரடை, பேரடைகளின் பட்டியல்

The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy distanced 21 million light-years (six megaparsecs)[1] away from earth in the constellation Ursa Major. First discovered by Pierre Méchain on March 27, 1781, it was communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final entries.

On February 28, 2006, நாசா and the European Space Agency released a very detailed image of the Pinwheel Galaxy, which was the largest and most detailed image of a galaxy by Hubble Space Telescope at the time.[2] The image was composed of 51 individual exposures, plus some extra ground-based photos.

On August 24, 2011, a Type Ia supernova, SN 2011fe, was discovered in M101.

Discovery தொகு

Pierre Méchain, the discoverer of Messier 101, described it as a "nebula without star, very obscure and pretty large, 6' to 7' in diameter, between the left hand of Bootes and the tail of the great Bear. It is difficult to distinguish when one lits the [grating] wires."[3]

William Herschel noted in 1784 that "...in my 7, 10, and 20-feet [focal length] reflectors shewed a mottled kind of nebulosity, which I shall call resolvable; so that I expect my present telescope will, perhaps, render the stars visible of which I suppose them to be composed."[3]

Lord Rosse observed M101 in his 72-inch diameter Newtonian reflector during the second half of the 19th century. He was the first to make extensive note of the spiral structure and made several sketches.[3]

To observe the spiral structure in modern instruments requires a fairly large instrument, very dark skies, and a low power eyepiece.[4]

Structure and composition தொகு

M101 - combined infrared, visible, and x-ray images.

M101 is a large galaxy, with a diameter of 170,000 light-years. By comparison, the Milky Way has a diameter of 100,000 light years. It has around a trillion stars, ten times the amount in the Milky Way.[5] It has a disk mass on the order of 100 billion solar masses, along with a small central bulge of about 3 billion solar masses.[6]

M101 is noted for its high population of H II regions, many of which are very large and bright. H II regions usually accompany the enormous clouds of high density molecular hydrogen gas contracting under their own gravitational force where stars form. H II regions are ionized by large numbers of extremely bright and hot young stars; those in M101 are capable of creating hot superbubbles.[7] In a 1990 study, 1264 H II regions were cataloged in the galaxy.[8] Three are prominent enough to receive New General Catalogue numbers - NGC 5461, NGC 5462, and NGC 5471.[9]

M101 is asymmetrical due to the tidal forces from interactions with its companion galaxies. These gravitational interactions compress interstellar hydrogen gas, which then triggers strong star formation activity in M101's spiral arms that can be detected in ultraviolet images.[10]

In 2001, the x-ray source P98, located in M101, was identified as an ultra-luminous X-ray source - a source more powerful than any single star but less powerful than a whole galaxy - using the Chandra X-ray Observatory. It received the designation M101 ULX-1. In 2005, Hubble and XMM-Newton observations showed the presence of an optical counterpart, strongly indicating that M101 ULX-1 is an x-ray binary.[11] Further observations showed that the system deviated from expected models - the black hole is just 20 to 30 solar masses, and consumes material (including captured stellar wind) at a higher rate than theory suggests.[12]

Companion galaxies தொகு

M101 has five prominent companion galaxies: NGC 5204, NGC 5474, NGC 5477, NGC 5585, and Holmberg IV.[13] As stated above, the gravitational interaction between M101 and its satellites may have triggered the formation of the grand design pattern in M101. M101 has also probably distorted the companion galaxy NGC 5474.[13] M101 and its companion galaxies comprise most or possibly all of the M101 Group.[14][15][16][17]

Supernovae தொகு

On August 24, 2011, a Type Ia supernova, SN 2011fe, initially designated PTF 11kly, was discovered in M101. The supernova was visual magnitude 17.2 at discovery and reached magnitude 9.9 at its peak.[18][19][20] This was the fourth supernova recorded in M101. The first, SN 1909A, was discovered by Max Wolf in January 1909 and reached magnitude 12.1. SN 1951H reached magnitude 17.5 in September 1951 and SN 1970G reached magnitude 11.5 in January 1970.[21] On February 10, 2015, a luminous red nova, known as M101 OT2015-1 was discovered in the Pinwheel Galaxy by Dumitru Ciprian Vîntdevară from Planetarium and Astronomical Observatory of the Museum Vasile Parvan in Bârlad, Romania.[22]

Gallery தொகு

See also தொகு

  • Messier 74 – a similar face-on spiral galaxy
  • Messier 83 – a similar face-on spiral galaxy that is sometimes called the Southern Pinwheel Galaxy
  • Messier 99 – a similar face-on spiral galaxy
  • Triangulum Galaxy – another galaxy sometimes called the Pinwheel Galaxy

References தொகு

  1. பிழை காட்டு: செல்லாத <ref> குறிச்சொல்; shappee என்னும் பெயரில் உள்ள ref குறிச்சொல்லுக்கு உரையேதும் வழங்கப்படவில்லை
  2. "Hubble's Largest Galaxy Portrait Offers a New High-Definition View". NASA. 28 February 2006. பார்க்கப்பட்ட நாள் 4 February 2018.
  3. 3.0 3.1 3.2 Hartmut Frommert. "Messier 101". SEDS Messier Database. பார்க்கப்பட்ட நாள் 4 March 2018.
  4. "M 101". Messier Objects Mobile — Charts, Maps & Photos. பார்க்கப்பட்ட நாள் 4 March 2018.
  5. Plait, Phil (2006-02-28). "Hubble delivers again: M101" (in en-US). Slate. http://www.slate.com/blogs/bad_astronomy/2006/02/28/hubble_delivers_again_m101.html. 
  6. Comte, G.; Monnet, G.; Rosado, M. (1979). "An optical study of the galaxy M 101 - Derivation of a mass model from the kinematic of the gas". Astronomy and Astrophysics 72: 73–81. Bibcode: 1979A&A....72...73C. 
  7. Immler, Stefan; Wang, Q. Daniel (2001). "ROSAT X-Ray Observations of the Spiral Galaxy M81". The Astrophysical Journal 554 (1): 202. doi:10.1086/321335. Bibcode: 2001ApJ...554..202I. http://iopscience.iop.org/0004-637X/554/1/202/. பார்த்த நாள்: 12 May 2014. 
  8. Hodge, Paul W.; Gurwell, Mark; Goldader, Jeffrey D.; Kennicutt, Robert C., Jr. (August 1990). "The H II regions of M101. I - an atlas of 1264 emission regions". Astrophysical Journal Supplement Series 73: 661–670. doi:10.1086/191483. Bibcode: 1990ApJS...73..661H. 
  9. Giannakopoulou-Creighton, J.; Fich, M.; Wilson, C. D. (1999). "Star formation in the giant HII regions of M101". The Astrophysical Journal 522: 238. doi:10.1086/307619. Bibcode: 1999ApJ...522..238G. 
  10. Waller, William H.; Bohlin, Ralph C.; Cornett, Robert H.; Fanelli, Michael N. et al. (20 May 1997). "Ultraviolet Signatures of Tidal Interaction in the Giant Spiral Galaxy M101". The Astrophysical Journal 481 (1): 169. doi:10.1086/304057. Bibcode: 1997ApJ...481..169W. http://iopscience.iop.org/0004-637X/481/1/169. பார்த்த நாள்: 12 May 2014. 
  11. Kuntz, K.D. (10 February 2005). "The Optical Counterpart of M101 ULX-1". The Astrophysical Journal 620 (1): L31–L34. doi:10.1086/428571. Bibcode: 2005ApJ...620L..31K. http://iopscience.iop.org/1538-4357/620/1/L31/fulltext/19014.text.html. பார்த்த நாள்: 12 May 2014. 
  12. Liu, Jifeng; Bregman, Joel N.; Bai, Yu; Justham, Stephen et al. (2013). "Puzzling accretion onto a black hole in the ultraluminous X-ray source M101 ULX-1". Nature 503 (7477): 500. doi:10.1038/nature12762. Bibcode: 2013Natur.503..500L. 
  13. 13.0 13.1 A. Sandage; J. Bedke (1994). Carnegie Atlas of Galaxies. Carnegie Institution of Washington. பன்னாட்டுத் தரப்புத்தக எண்:0-87279-667-1. 
  14. R. B. Tully (1988). Nearby Galaxies Catalog. கேம்பிறிட்ஜ் பல்கலைக்கழகப் பதிப்பகம். பன்னாட்டுத் தரப்புத்தக எண்:0-521-35299-1. 
  15. P. Fouque; E. Gourgoulhon; P. Chamaraux; G. Paturel (1992). "Groups of galaxies within 80 Mpc. II – The catalogue of groups and group members". Astronomy and Astrophysics Supplement 93: 211–233. Bibcode: 1992A&AS...93..211F. 
  16. A. Garcia (1993). "General study of group membership. II – Determination of nearby groups". Astronomy and Astrophysics Supplement 100: 47–90. Bibcode: 1993A&AS..100...47G. 
  17. Giuricin, G.; Marinoni, C.; Ceriani, L.; Pisani, A. (2000). "Nearby Optical Galaxies: Selection of the Sample and Identification of Groups". Astrophysical Journal 543 (1): 178–194. doi:10.1086/317070. Bibcode: 2000ApJ...543..178G. 
  18. Nugent, Peter; et al. (24 August 2011). "Young Type Ia Supernova PTF11kly in M101". The Astronomer's Telegram. பார்க்கப்பட்ட நாள் 25 August 2011.
  19. Nugent, Peter; et al. "Supernova Caught in the Act". பார்க்கப்பட்ட நாள் 7 September 2011.
  20. Hartmut Frommert; Christine Kronberg (15 Sep 2011). "Supernova 2011fe in M101". பார்க்கப்பட்ட நாள் 17 Sep 2011. {{cite web}}: Unknown parameter |last-author-amp= ignored (help)
  21. Stoyan, Ronald Atlas of the Messier Objects, Cambridge University Press 2008 page 329
  22. "Transient object followup reports". Central Bureau for Astronomical Telegrams.

External links தொகு

விக்கிமீடியா பொதுவகத்தில்,
Pinwheel Galaxy
என்பதில் ஊடகங்கள் உள்ளன.

ஆள்கூறுகள்:   14h 03m 12.6s, +54° 20′ 57″

வார்ப்புரு:Messier objects வார்ப்புரு:Ngc55

"https://ta.wikipedia.org/w/index.php?title=பயனர்:TNSE_MANI_VNR/மணல்தொட்டி&oldid=3316621" இலிருந்து மீள்விக்கப்பட்டது