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Sh 2-87, Sh 2-88, Vulpecula

Sh 2-87, Sh 2-88, Vulpecula

530 mm f/5 20 hours, July 2013, Photograph

Sh 2-88 — The diffuse HII region Sh 2-88, excited by the massive O8 star BD +25°3952, appears surrounded by a neutral hydrogen HI struture of 9 x 6 pc in radius. The neutral and ionized masses associated with Sh 2-88 are about 150 and 410 Msolar, respectively, and the dust mass is 2 to 9 Msolar. The rms electron density is 9 cm-3. Sh 2-88 appears to be interacting with an approaching part of an HI bubble shaped by the stellar winds of BD +25°3952 and the massive O8.5II(f) star BD +25°3866. The whole structure is located at a distance of about 2.4 kpc, is 23 x 15 pc in radius, has a dynamical age of 1.5 Myr and a mass of 1300 Msolar. From Cappa et al., "An HI interstellar bubble linked to the O-type stars BD +24°3866 and BD +25°3952", Astronomy & Astrophysics, 395:955-967, 2002.

Sh 2-88A/B — Two nebular knots, Sh 2-88A and Sh 2-88B, are located southeast of Sh 2-88. The exciting star of Sh 2-88A is the spectral type B... star LSII +25°9. Sh 2-88B is a region of active star formation as indicated by the presense of water maser emission lines and bipolar outflows. Sh 2-88B has two components, called Sh 2-88B1 and Sh 2-88B2. B1 is a compact cometary HII region associated with a cluster containing several massive stars. The dominant exciting star, at the center of the cometary structure, has an ionizing radiation flux corresponding to a spectral type in the range O8.5V-O9.5V. It is high reddened, with a visual extinction in the 30 to 42 magnitude range, and exhibits near-IR excess. B1 has a simple morphology, with the ionized and neutral gas clearly separated. Its infrared band emission comes from the photodissociation region at the periphery of the ionized gas. B2 is an ultracompact HII region whose exciting star, probably of spectral type later than B0.5V, is not detected; this indicates a visual extinction greater than 60 magnitudes. From Deharveng et al., "The stellar content of the compact H II region Sh2-88B", Astronomy and Astrophysics, 360:1107-1116, 2000.

G61.48+0.09 — The star forming region G61.48+0.09, surrounded by the HII region Sh 2-88B, was studied photometrically and spectoscopically in the near-infrared by Marín-Franch et al. Of the twenty cluster members selected for spectroscopy, two stars were found to have emission lines and six were found to be late-O or early-B type. The cluster is located at ~2.5 kpc, has a visual extinction between 8 and 23 magnitudes, is younger than 10 Myr and has a minimum mass of 1500 Msolar. From Marín-Franch et al., "The stellar population of the star-forming regions G61.48+0.09", Astronomy and Astrophysics, 502:559-567, 2009.

Sh 2-87 — Sh 2-87 is a star-forming HII complex located at a distance of about 2.3 kpc. It is associated with infrared sources, water maser emission lines and bipolar outflows. Sh 2-87 harbors two infrared star clusters, Sh 2-87E and Sh 2-87W. Submillimeter continuum emission measurements of the Sh 2-87E neighborhood reveal three individual molecular clumps with masses about 100 to 200 Msolar and average dust temperatures about 20 to 40 K. Two of these clumps appear to be star-forming sites, the third a cold, starless core. From Xue et al., "A multiwavelength study of the massive star-forming regions S87", The Astrophysical Journal, 680(1):446-456, June 2008.

VulP7, VulP8, VulP9 — VulP7, VulP8 and VulP9 are pillar-like structures similar to the archetypal pillars of creation in M16. Such pillars are associated with recent episodes of star formation as winds and radiation emanating from young massive stars are responsible for sculpting these elongated elephant trunks out of the surrounding molecular material. Pressure at the surface of the pillars due to strong external radiation appears to trigger the formation of new stars. The scupltor of these pillar is thought to be an unidentified source in a diffuse faint circular structure located outside the photograph. From Billot et al., "Young Stellar Objects and Triggered Star Formation in the Vulpecula OB association", The Astrophysical Journal, 712(2):797-812, April 2010.

Vul OB1 — The Vulpecula OB assocation, Vul OB1, hosts nearly one hundred OB stars including those labeled inside the photograph, three HII regions Sh 2-88, Sh 2-87 and Sh 2-86 located outside the photograph and the young star clusters NGC 6823 and Cr 404 located outside the photograph. The molecular complex has a diameter of about 100 pc. Over 850 Young Stellar Object (YSO) candidates have been detected in Vul OB1. The evolutionary state of the YSO population is homogeneous. The Vul OB1 gas reservoir cloud mass and YSO population total mass are about 45 kMsolar and 4.2 kMsolar, respectively, and the star formation efficiency is about 8%. From Billot, et al., "Young Stellar Objects and Triggered Star Formation in the Vulpecula OB association", The Astrophysical Journal, 712(2):797-812, April 2010.

Coordinates: RA 19h 46.3m, Dec +25° 0’, PA +0° 21’
Field of view: 1° 56’ x 1° 28’
Image scale: 4.2” / pixel

Date: July 2013
Location: Cascade and Santa Lucia Range, California
Exposure: 30 x 40 minutes (20 hours), binned 2 x 2 at -20° C

Zenith SQM: 21.5 mag / "²
Guiding error: 0.8" rms
Star FWHM: 4.4", histogram
Star eccentricity: 0.39
Camera noise: 15 e- rms
Background noise: 23 e- rms
Subframe location: 226 e-
Subframe scale: 51 e-

Telescope: Takahashi FSQ-106EDX 530 mm f/5
Camera: Quantum Scientific Imaging 683wsg
Filter: Astrodon H-alpha, 3 nm bandwidth
Focuser: Finger Lakes Instrumentation Atlas, Quality Thermistor DirecTemp DTU6024C, Spike-a Bahtinov Mask
Guider: Santa Barbara Instrument Group ST-i
Flats: Alnitak Astrosystems Flat-Man
USB: Icron Ranger 2122, Moxa UPort 404
Mount: Takahashi EM-400 Temma2M
Acquisition: Diffraction Limited MaxIm DL, CCDAstro Temma, IHRP Platform, ASCOM Platform
Processing: Pleiades Astrophoto PixInsight, MathWorks MATLAB, IHRP Platform