Object type | H II region, star cluster |
---|---|
Other designations | W40, Sh2-64, RCW 174, LBN 90 |
Constellation | Serpens Cauda |
18 31 29 | |
Declination | -02 05.4 |
Distance | 1420±30 ly[1] / 436±9 pc |
In visual light (V) | |
Size | 8 arcminutes[2] |
Radius | 1.65 ly |
Estimated age | 0.8–1.5 Myr[3] |
Related media on Wikimedia Commons | |
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]
OrtizLeon16
was invoked but never defined (see the help page).kuhn10
was invoked but never defined (see the help page).getman14
was invoked but never defined (see the help page).reipurth08
was invoked but never defined (see the help page).Mallick
was invoked but never defined (see the help page).shuping12
was invoked but never defined (see the help page).vallee87
was invoked but never defined (see the help page).sofia
was invoked but never defined (see the help page).Rumble2016
was invoked but never defined (see the help page).Shimoikura2015
was invoked but never defined (see the help page).gutermuth08
was invoked but never defined (see the help page).SerpensCluster
was invoked but never defined (see the help page).