Wolf-Lundmark-Melotte

Wolf-Lundmark-Melotte
Wolf-Lundmark-Melotte Galaxy
Wlm galaxy.jpg
Wolf-Lundmark-Melotte galaxy.
Observation data (J2000 epoch)
Constellation Cetus
Right ascension 00h 01m 58.1s[1]
Declination -15° 27′ 39″[1]
Redshift -122 ± 2 km/s[1]
Distance 3.04 ± 0.11 Mly (930 ± 30 kpc)[2]
Type IB(s)m[1]
Apparent dimensions (V) 11′.5 × 4′.2[1]
Apparent magnitude (V) 11.0[1]
Notable features -
Other designations
WLM,[1] DDO 221,[1] UGCA 444,[1] PGC 143[1]
See also: Galaxy, List of galaxies

The Wolf-Lundmark-Melotte (WLM) galaxy is an irregular galaxy discovered in 1909 by Max Wolf, and is located on the outer edges of the local group. The discovery of the nature of the galaxy was accredited to Knut Lundmark and Philibert Jacques Melotte in 1926. It is in the constellation Cetus.

Contents

Star formation

In 1994, A. E. Dolphin used the Hubble Space Telescope to create a color-magnitude diagram for WLM. It showed that around half of all the star formation in this galaxy occurred during a burst that started ~13 Gyr ago. During the burst, the metallicity of WLM rose from [Fe/H] ~ -2.2 to [Fe/H] -1.3. There being no horizontal-branch population, Dolphin concludes that no more than ~20 M per Myr of star formation occurred in the period from 12 to 15 Gyr ago. From 2.5 to 9 Gyr ago, the mean rate of star formation was 100 to 200 M per Myr.[3]

Globular cluster

WLM has one known globular cluster that Hodge et al. (1999) determined has Mv = -8.8 and [Fe/H] = -1.5 with an age of ~15 Gyr. This cluster has a luminosity that is slightly over the average for all globulars. The seeming lack of faint low-mass globular clusters can not be explained by the weak tidal forces of the WLM system.[3]

References in fiction

In E.E. Smith’s Lensman novels, the "Second Galaxy" is identified as “Lundmark’s Nebula.”[4] However, some believe the "Second Galaxy" may not be the Wolf-Lundmark-Melotte galaxy, since the first chapter of the first novel in the series (Triplanetary) and the series-establishing material appearing at the beginning of subsequent novels states that the "Second Galaxy" and the "First Galaxy" (the Milky Way) collided and passed through each other "edge-on" during the "planet-forming era" — implying that the "Lundmark's Nebula" of the series must necessarily be obscured from view by the Milky Way; however, according to others, it could have passed through at an angle and thus be identified with the galaxy described in this article; obviously, this is the galaxy that E.E. Smith was thinking of when he wrote the series. At the time the Lensman series was written, most astronomers favored the tidal theory of solar system formation, which required that planets be formed by the close approach of another star. In order to produce the massive numbers of planets necessary to evolve into the galactic civilizations in both our Galaxy and Lundmark's Nebula portrayed in the Lensman series, E.E. Smith felt it would have been necessary for another galaxy to have passed through our galaxy in the past to produce the large number of close encounters necessary to form so many planets.

References

  1. ^ a b c d e f g h i j "NASA/IPAC Extragalactic Database". Results for WLM. http://nedwww.ipac.caltech.edu/. Retrieved 2006-12-23. 
  2. ^ McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N. (2005). "Distances and metallicities for 17 Local Group galaxies". Monthly Notices of the Royal Astronomical Society 356 (4): 979–997. arXiv:astro-ph/0410489. Bibcode 2005MNRAS.356..979M. doi:10.1111/j.1365-2966.2004.08514.x. 
  3. ^ a b van den Bergh, Sidney (April 2000). "Updated Information on the Local Group". The Publications of the Astronomical Society of the Pacific 112 (770): 529–536. arXiv:astro-ph/0001040. Bibcode 2000PASP..112..529V. doi:10.1086/316548 
  4. ^ E.E. Smith (1939, 1951). Gray Lensman. Gnome. ISBN 978-1882968121.  p. 66, Ron Ellik, Bill Evans, and Al Lewis (1966). The Universes of E.E. Smith. Advent. ISBN 0-911682-03-1.  p. 121.

Coordinates: Sky map 00h 01m 58.1s, −15° 27′ 39″


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Wolf-Lundmark-Melotte — Galaxie Die Wolf Lundmark Melotte Galaxie ist eine Irreguläre Galaxie. Sie wurde nach den Astronomen Max Wolf, Knut Lundmark und Philibert Jacques Melotte benannt. Die Galaxie ist ein Mitglied der Lokalen Gruppe in 0.86 Mpc Entfernung …   Deutsch Wikipedia

  • Wolf-Lundmark-Melotte — Datos de observación (Época J2000.0) Tipo IB(s)m …   Wikipedia Español

  • Wolf-Lundmark-Melotte — Галактика …   Википедия

  • Wolf-Lundmark-Melotte-Galaxie — Die Wolf Lundmark Melotte Galaxie ist eine Irreguläre Galaxie. Sie wurde nach den Astronomen Max Wolf, Knut Lundmark und Philibert Jacques Melotte benannt. Die Galaxie ist ein Mitglied der Lokalen Gruppe in 0,86 Mpc Entfernung …   Deutsch Wikipedia

  • Galaxie De Wolf-Lundmark-Melotte — Pour les articles homonymes, voir Lundmark. Wolf Lundmark Melotte …   Wikipédia en Français

  • Galaxie de wolf-lundmark-melotte — Pour les articles homonymes, voir Lundmark. Wolf Lundmark Melotte …   Wikipédia en Français

  • Galaxie de Wolf-Lundmark-Melotte — Pour les articles homonymes, voir Lundmark. Wolf Lundmark Melotte Galaxie de Wolf Lundmark Melotte, photographiée par l’ESO …   Wikipédia en Français

  • Lundmark — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Lundmark peut se référer à : Knut Lundmark, un astronome suédois ; Lundmark, un cratère d impact lunaire ; La galaxie de Wolf Lundmark… …   Wikipédia en Français

  • Knut Emil Lundmark — Knut Lundmark 1908 Knut Emil Lundmark (* 14. Juni 1889 in Älvsbyn, Norrbottens län; † 23. April 1958 in Lund) war ein schwedischer Astronom, und von 1929 bis 1955 Astronomieprofessor und Direktor des …   Deutsch Wikipedia

  • K. E. Lundmark — Knut Lundmark Pour les articles homonymes, voir Lundmark. Knut Lundmark 1908. Kn …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”