Westerhout 40

W 40
W40 as seen in the infrared by the Spitzer Space Telescope.
Object typeH II region, star cluster Edit this on Wikidata
Other designationsW40, Sh2-64, RCW 174, LBN 90
Observation data
(Epoch J2000)
ConstellationSerpens Cauda
18 31 29
Declination-02 05.4
Distance1420±30 ly[1] / 436±9 pc
In visual light (V)
Size
8 arcminutes[2]
Radius1.65 ly
Estimated age0.8–1.5 Myr[3]
Related media on Wikimedia Commons
[edit on Wikidata]

Westerhout 40 or W40 (also designated Sharpless 64, Sh2-64, or RCW 174) is a star-forming region in the Milky Way located in the constellation Serpens. In this region, interstellar gas forming a diffuse nebula surrounds a cluster of several hundred new-born stars.[2][4][5] The distance to W40 is 436 ± 9 pc (1420 ± 30 light years),[1] making it one of the closest sites of formation of high-mass O-type and B-type stars.[6] The ionizing radiation from the massive OB stars has created an H II region,[7] which has an hour-glass morphology.[4]

Dust from the molecular cloud in which W40 formed obscures the nebula, rendering W40 difficult to observe at visible wavelengths of light.[2][8] Thus, X-ray, infrared, and radio observations have been used to see through the molecular cloud to study the star-formation processes going on within.[2][9][10]

W40 appears near to several other star-forming regions in the sky, including an infrared dark cloud designated Serpens South[11] and a young stellar cluster designated the Serpens Main Cluster.[12] Similar distances measured for these three star-forming regions suggests that they are near to each other and part of the same larger-scale collection of clouds known as the Serpens Molecular Cloud.[1]

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  2. ^ a b c d Cite error: The named reference kuhn10 was invoked but never defined (see the help page).
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  4. ^ a b Cite error: The named reference reipurth08 was invoked but never defined (see the help page).
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  9. ^ Cite error: The named reference Rumble2016 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Shimoikura2015 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference gutermuth08 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SerpensCluster was invoked but never defined (see the help page).