Sh 2-171
Coordinates: (118.41°, 4.68°)
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This expanding shell of gas and dust was created by the original star cluster at the heart of the Cep OB4 association, which has now dispersed. It is now lit and ionized by the young star cluster Berkeley 59 (forming the bright nebula called Cederblad 214) and it is expanding into the fainter diffuse nebula NGC 7822. Berkeley 59 is surrounded by another dark region of disturbed gas and dust containing the radio source W1.
Avedisova lists 4 O-stars that ionise this nebula. The hottest of these is the O7 V BD +66 1675. She places Sh 2-171 in star formation region SFR 118.41+4.68 with 46 components, including 3 masers, 14 infrared sources and the dark nebula LDN 1271.
A 2008 study adds a fifth ionising O-star to Berkeley 59, hotter than than any of the ones Avedisova identified. Spectographic analysis reveals that BD +66 1673 has a class of O5 V((f))n. The same study concludes that Berkeley 59 is 2 million years old. A second 2008 study agrees on the age and comments that Berkeley 59 has nine ionising stars in total (classes O-B3).
There are more details on this nebula in the Cep OB4 section of the description of the Brain and Bubble (120° - 110°) sector of the Commentary on the Galactic Plane. You can also see the location of Cep OB4 and Sh 2-171 within the relatively nearby Cepheus molecular clouds on this face-on map.
You can see a spectacular image of this region here and view the large shell surrounding the nebula in visual light and in this IRAS infrared image.
Avedisova lists 4 O-stars that ionise this nebula. The hottest of these is the O7 V BD +66 1675. She places Sh 2-171 in star formation region SFR 118.41+4.68 with 46 components, including 3 masers, 14 infrared sources and the dark nebula LDN 1271.
A 2008 study adds a fifth ionising O-star to Berkeley 59, hotter than than any of the ones Avedisova identified. Spectographic analysis reveals that BD +66 1673 has a class of O5 V((f))n. The same study concludes that Berkeley 59 is 2 million years old. A second 2008 study agrees on the age and comments that Berkeley 59 has nine ionising stars in total (classes O-B3).
There are more details on this nebula in the Cep OB4 section of the description of the Brain and Bubble (120° - 110°) sector of the Commentary on the Galactic Plane. You can also see the location of Cep OB4 and Sh 2-171 within the relatively nearby Cepheus molecular clouds on this face-on map.
You can see a spectacular image of this region here and view the large shell surrounding the nebula in visual light and in this IRAS infrared image.
Berkeley 59 has nine ionising stars in total (O-B3), an age of 2 million years and a distance of 1000 +/- 50 parsecs.[1]
For one of the eclipsing systems, BD+66°1673, spectroscopic observations reveal it to be an O5 V((f))n star and the probable ionizing star of the Berkeley 59/Cep OB4 complex. An analysis of spectroscopic observations and BV photometry for Berkeley 59 members in conjunction with published observations imply a cluster age of ~2 Myr, a distance of d = 883 ±43 pc, and a reddening of EB-V = 1.38 ±0.02.[2]
For one of the eclipsing systems, BD+66°1673, spectroscopic observations reveal it to be an O5 V((f))n star and the probable ionizing star of the Berkeley 59/Cep OB4 complex. An analysis of spectroscopic observations and BV photometry for Berkeley 59 members in conjunction with published observations imply a cluster age of ~2 Myr, a distance of d = 883 ±43 pc, and a reddening of EB-V = 1.38 ±0.02.[2]
Notes
1. ^ Pandey, A. K., Sharma, Saurabh, Ogura, K., et al. (2008). "Stellar contents and star formation in the young star cluster Be 59", Monthly Notices of the Royal Astronomical Society, Vol. 383, 1241-1258. [2008MNRAS.383.1241P]
2. ^ Majaess, D. J., Turner, D. G., Lane, D. J., et al. (2008). "The Exciting Star of the Berkeley 59/Cepheus OB4 Complex and Other Chance Variable Star Discoveries", Journal of the American Association of Variable Star Observers (JAAVSO), Vol. 36, 90. [2008JAVSO..36...90M]
Distance estimates
840 pc [1982ApJS...49..183B]790 pc +/- 110 [1984NInfo..56...59A]
883 pc +/- 43 [2008JAVSO..36...90M]
1000 pc +/- 50 [2008MNRAS.383.1241P]
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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
on the general history of this area of astronomy.
This image was created using the POSS-II/UKSTU data of the Digitized Sky Survey and SuperCOSMOS using the process described here.
According to my correspondence with the Royal Observatory Edinburgh and the Space Telescope Science Institute, I am allowed to use the POSS-II/UKSTU data to create and display images for non-commercial purposes so long as I include this fine print for the SuperCOSMOS data:
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.
The "Second Epoch Survey" of the southern sky was made by the Anglo-Australian Observatory (AAO) with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright ? 1993-5 by the Anglo-Australian Observatory Board, and are distributed herein by agreement.
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.