Westerhout 5

Westerhout 5

Emission nebula
H II region
File:Celestial Valentine.jpg Detail of Westerhout 5
Observation data: J2000.0 epoch
Right ascension	02h 55m 24s
Declination	+60° 24′ 36″
Distance	7,500 ly
Apparent dimensions (V)	150' x 75'
Constellation	Cassiopeia
Physical characteristics
Absolute magnitude (V)	6.5
Designations	Sh2-199, LBN 667 - Cluster is IC1848

Westerhout 5 (Sharpless 2-199, LBN 667, Soul Nebula) is emission nebulae in Cassiopeia. Several small open clusters are embedded in the nebula: CR 34, 632, and 634 (in the head) and IC1848 (in the body). The object is more commonly called by the cluster designation IC1848.

Small emission nebula IC 1871 is present just left of the top of the head, and small emission nebulae 670 and 669 are just below the lower back area.

This complex is the eastern neighbor of IC1805 (Heart Nebula) and the two are often mentioned together as the "Heart and Soul".

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  Generations of stars can be seen in this infrared portrait from NASA's Spitzer Space Telescope.

• Heart and Soul nebulae.jpg

  The Heart Nebula and Westerhout 5 are seen in this infrared mosaic from NASA's WISE telescope.

Star formation

File:The W5 Stellar Blast Furnace.ogv

The W5 stellar blast furnace.

W5, a radio source within the nebula, spans an area of sky equivalent to four full moons and is about 6,500 light-years away in the constellation Cassiopeia. Like other massive star-forming regions, such as Orion and Carina, W5 contains large cavities that were carved out by radiation and winds from the region's most massive stars. According to the theory of triggered star formation, the carving out of these cavities pushes gas together, causing it to ignite into successive generations of new stars. The image in the gallery above contains some of the best evidence yet for the triggered star formation theory. Scientists analyzing the photo have been able to show that the ages of the stars become progressively and systematically younger with distance from the center of the cavities.