Cannabaceae

NGC 2950
SDSS image of NGC 2950 (center)
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension09h 42m 35.116s[1]
Declination58° 51′ 04.39″[1]
Redshift0.004410 ± 0.000017
Heliocentric radial velocity1,329[2] km/s
Distance49.84 ± 0.46 Mly (15.28 ± 0.14 Mpc)[2]
Apparent magnitude (B)11.93[2]
Characteristics
TypeRSB0(r)[3]
Apparent size (V)2′.7 × 1′.8[3]
Other designations
NGC 2950, UGC 5176, PGC 27765[4]

NGC 2950 is a lenticular galaxy in the northern constellation of Ursa Major, about 50 million light years from the Milky Way and receding with a heliocentric radial velocity of 1,329 km/s.[2] It was discovered in 1790 by the Anglo-German astronomer William Herschel.[5] NGC 2950 is a field galaxy, it is not part of a galaxy cluster or galaxy group, and thus is gravitationally isolated.[6] Nine certain and four possible dwarf galaxies have been identified around NGC 2950.[7]

The morphological classification of this galaxy is RSB0(r),[3] indicating a barred lenticular galaxy (SB0) with outer (R) and inner (r) ring structures. It hosts two nested stellar bars; the rotation frequency of the secondary bar is higher than that of the primary one.[3] Double bars of this type are relatively common, having been found in ~30% of barred lenticulars. The inner bar appears to be counter-rotating relative to the outer bar,[8] with the two passing cleanly through each other.[9] The stellar mass of the galaxy is 1.7×1010 M while the halo mass is 6.6×1011 M.[7]

References

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  1. ^ a b Skrutskie, Michael F.; et al. (February 1, 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708. ISSN 0004-6256. S2CID 18913331.
  2. ^ a b c d Tully, R. Brent; et al. (October 2013), "Cosmicflows-2: The Data", The Astronomical Journal, 146 (4): 25, arXiv:1307.7213, Bibcode:2013AJ....146...86T, doi:10.1088/0004-6256/146/4/86, S2CID 118494842, 86
  3. ^ a b c d Corsini, E. M.; et al. (December 2003). "Direct Confirmation of Two Pattern Speeds in the Double-barred Galaxy NGC 2950". The Astrophysical Journal. 599 (1): L29–L32. arXiv:astro-ph/0310879. Bibcode:2003ApJ...599L..29C. doi:10.1086/381080. S2CID 13102437.
  4. ^ "NGC 2950". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-16.
  5. ^ Seligman, Courtney (2016). "NGC 2950 (= PGC 27765)". Celestial Atlas. Professor Seligman. Retrieved May 1, 2020.
  6. ^ "NASA/IPAC Extragalactic Database". Results for NGC 2950. Retrieved October 28, 2018.
  7. ^ a b Tanaka, Masayuki; et al. (October 2018). "The Missing Satellite Problem Outside of the Local Group. I. Pilot Observation". The Astrophysical Journal. 865 (2): 12. arXiv:1808.03410. Bibcode:2018ApJ...865..125T. doi:10.3847/1538-4357/aad9fe. S2CID 119244164. 125.
  8. ^ Maciejewski, Witold (September 2006). "Response of the integrals in the Tremaine-Weinberg method to multiple pattern speeds: a counter-rotating inner bar in NGC 2950?". Monthly Notices of the Royal Astronomical Society. 371 (1): 451–458. arXiv:astro-ph/0602520. Bibcode:2006MNRAS.371..451M. doi:10.1111/j.1365-2966.2006.10679.x. S2CID 16623123.
  9. ^ Maciejewski, W. (October 2008). Funes, José G.; J., S.; Corsini, Enrico Maria (eds.). Orbits in Corotating and Counterrotating Double Bars. Proceedings of the conference held 1-5 October, 2007 at the Centro Convegni Matteo Ricci, Rome, Italy. Formation and Evolution of Galaxy Disks ASP Conference Series. Vol. 396. San Francisco: Astronomical Society of the Pacific. p. 367. arXiv:0801.1471. Bibcode:2008ASPC..396..367M.
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  • Media related to NGC 2950 at Wikimedia Commons

One thought on “Cannabaceae

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
    View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction

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