Sh2-1, also known as
Sharpless 1, is the combination of a diffuse HII
emission nebula
An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star. Among the several different types of emissio ...
and
reflection nebula Reflection or reflexion may refer to:
Science and technology
* Reflection (physics), a common wave phenomenon
** Specular reflection, reflection from a smooth surface
*** Mirror image, a reflection in a mirror or in water
** Signal reflection, in s ...
in the constellation of
Scorpius
Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation that pre-dates the Gre ...
with
Pi Scorpii
Pi Scorpii or π Scorpii, is a triple star system in the southern constellation of Scorpius. With a combined apparent magnitude of 2.9, it can be easily seen with the naked eye. Parallax measurements yield an estimated distance of around ...
at its center. It appears as a modest brightness making it one of the easier
Sharpless catalog
The Sharpless catalog is a list of 313 H II regions (emission nebulae) intended to be comprehensive north of declination −27°. (It does include some nebulae south of that declination as well.) The first edition was published in 1953 with 14 ...
objects for amateur astronomers to view. It features an apparent central star inside the nebulosity however it is not part its system nor a left over remnant.
The nebulous area is fairly large with an irregular shape appearing as a 180
° arc shape surrounding a central star.
The remnant has an
apparent diameter
The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ...
that covers approximately 150
' and an estimated distance of approximately 650
ly away.
References
External links
*
Reflection nebulae
Diffuse nebulae
Scorpius
Sharpless objects
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