Sh 2-154
Coordinates: (108.96°, 1.59°)
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Sh 2-154 is ionised by the B0 III giant LS III +60 28, according to Avedisova. She places the nebula in the star formation region SFR 108.96+1.59 along with a molecular cloud.
According to a 2000 paper, radiation from stars associated with Sh 2-154 may be accelerating a giant molecular cloud that appears to contain 700 solar masses of carbon monoxide and perhaps 10 thousand solar masses in total viral mass.
According to a 2000 paper, radiation from stars associated with Sh 2-154 may be accelerating a giant molecular cloud that appears to contain 700 solar masses of carbon monoxide and perhaps 10 thousand solar masses in total viral mass.
The molecular cloud mentioned by Avedisova in association with Sh 2-154 appears to be [YDM97] CO 45 from the position and bibliographic reference she provides. However this cloud, which contains 200 solar masses of radioactive 13CO, has an estimated distance of 730 parsecs. [1] This may be a case where the photometric distance to the ionising star is larger than the kinematic distance of the surrounding gas.
Sh 2-154 is associated with a giant molecular cloud that appears to contain 700 solar masses of carbon monoxide and perhaps 10 thousand solar masses in total (viral mass). It is possible that this cloud is found within the Cepheus molecular clouds and only appears to be further away because the gas has been accelerated by star formation within the cloud.[2]
Sh 2-154 is associated with a giant molecular cloud that appears to contain 700 solar masses of carbon monoxide and perhaps 10 thousand solar masses in total (viral mass). It is possible that this cloud is found within the Cepheus molecular clouds and only appears to be further away because the gas has been accelerated by star formation within the cloud.[2]
Notes
1. ^ Yonekura, Yoshinori, Dobashi, Kazuhito, Mizuno, Akira, et al. (1997). "Molecular Clouds in Cepheus and Cassiopeia", The Astrophysical Journal Supplement Series, Vol. 110, 21. [1997ApJS..110...21Y]
2. ^ Ungerechts, H., Umbanhowar, P., & Thaddeus, P. (2000). "A CO Survey of Giant Molecular Clouds near Cassiopeia A and NGC 7538", The Astrophysical Journal, Vol. 537, 221-235. [2000ApJ...537..221U]
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Most of the sources used to create these nebula descriptions are listed in the
notes section for each description. In some cases,
for example the Avedisova, Humphreys and Reed catalogs, the source is used extensively and is not listed in the
individual nebula descriptions. See this catalog overview
for more information on the catalogs and the general sources used
to create these descriptions and this introduction to HII regions
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This image was created using the POSS-II/UKSTU data of the Digitized Sky Survey and SuperCOSMOS using the process described here.
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Use of these images is courtesy of the UK Schmidt Telescope (copyright in which is owned by the Particle Physics and Astronomy Research Council of the UK and the Anglo-Australian Telescope Board) and the Southern Sky Survey as created by the SuperCOSMOS measuring machine and are reproduced here with permission from the Royal Observatory Edinburgh.
and this acknowledgement taken from the DSS site:
The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.
The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation.
The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt.
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The "Equatorial Red Atlas" of the southern sky was made with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright ? 1992-5, jointly by the UK SERC/PPARC (Particle Physics and Astronomy Research Council, formerly Science and Engineering Research Council) and the Anglo-Australian Telescope Board, and are distributed herein by agreement.
The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright ? 1993-1995 by the California Institute of Technology and are distributed herein by agreement. The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright ? 1993-1995 by the California Institute of Technology and are distributed herein by agreement.