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IC 1318b/c, LDN 889, Cygnus

IC 1318b/c, LDN 889, Cygnus

530 mm f/5 12 hours, June 2012, Photograph

Gamma Cygni — Although Gamma Cygni is one of the brighter stars visible in the sky at magnitude +2.23, it has not been well studied. Gamma Cygni is classed at F8Iab, a supergiant near the instability strip of the H-R diagram. The spectrum of the star shows small-amplitude, irregular variations in radial velocity and line shape. The characteristics of these variations imply large-scale expansions and contractions with time scales ~100 days or longer. Magnitude +2.23, mass ~10 +/- 1 Msolar, radius 150 +/- 80 Rsolar, luminosity 33,000 Lsolar, temperature 5800 +/- 100 K, distance 467 +/- 90 pc, age 12 Myr. From Gray, "Photospheric Variations of the Supergiant γ Cyg", The Astronomical Journal, 140(5):1329–1336, 2010, November.

IC 1318b/c and LDN 889 — The IC 1318b/c regions are part of a single radio prominent HII region bisected by the massive dust lane LDN 889. All are components of the Cygnus-X complex of molecular clouds, one of the richest aggregates of star forming regions in our galactic neighborhood. Distance 1.5 kpc. From Comerón et al., "Near-infrared imaging of compact HII regions in Cygnus-X", Astronomy & Astrophysics, 375(2):539-552, 2001 August.

NGC 6910 —The young open cluster NGC 6910 of Trumpler class IV3p, the core of the Cygnus OB9 association, lies in the vicinity of the HII region IC 1318b. The ten brightest members of the cluster have spectral types between O9 and B2. Delgado et al. identify 11 stars of spectral types from A to G as probably pre–main-sequence stars in the cluster. Distance 1750 +/- 150 pc, age 6.5 +/- 3 Myr. From Delgado et al., "Search for pre–main-sequence stars in the young galactic cluster NGC 6910", The Astronomical Journal, 119(4):1848-1854, 2000 April.

V2118 Cyg — The B1.5Iae pulsating variable supergiant star V2118 Cyg is the brightest member of the open cluster NGC 6910. The star's spectrum shows a P Cygni-type profile of its H-alpha recombination line. The presense of both blueshifted absorption and redshifted emission lobes indicates the existence of a gaseous envelop expanding away from the star. Magnitude range +7.12 to +7.20. From Kubát et al., "The H-alpha stellar and interstellar emission in the open cluster NGC 6910", Astronomy & Astrophysics, 472(1):163-167, 2007 September.

V455 Cyg — V455 Cyg is a close eclipsing binary system of the Beta Lyrae type. The semi detached system is in an interacting stage of mass exchange, with the hotter star having an geometrically and optically thick accretion disc, and the cooler star filling it Ronche-lobe and streaming gas to its companion. The change in shape of its light curves, including prominent variations in the depth of the eclipses, can be explained by the changes in the parameters of the accretion disc and the active regions of the disc, arising in turn from a variable rate of mass transfer. Magnitude range +9.30 to +9.77, period 8.75 days. From Djurašević, et al., A study of the interacting binary system V455 Cygni, Monthly Notices of the Royal Astronomical Society, 420(4):3081-3090, 2012 March.

KX Cyg — KX Cyg is a classical Cepheid, or Delta Cephei-type (DCEP) variable. It is a comparatively young star that has left the main sequence and evolved into the instability strip of the Hertzsprung-Russel (H-R) diagram. It obeys the well-known Cepheid period-luminosity relation and belongs to the young disk population. Period 20.05 days, magnitude range +13.2 to +15.0. From AAVSO, The International Variable Star Index, www.aavso.org/vsx/index.php.

Coordinates: RA 20h 25.1m, Dec +40° 19’, PA +0° 3’
Field of view: 1° 56’ x 1° 28’
Image scale: 4.2” / pixel

Date: June 2012
Location: Santa Lucia Range, California
Exposure: 18 x 40 minutes (12 hours), binned 2 x 2 at -20° C

Guiding error: 0.7" rms
Star FWHM: 4.3", histogram
Star eccentricity: 0.37
Camera noise: 14 e- rms
Background noise: 22 e- rms
Subframe location: 623 e-
Subframe scale: 328 e-

Telescope: Takahashi FSQ-106EDX 530 mm f/5
Camera: Quantum Scientific Imaging 683wsg
Filter: Astrodon H-alpha, 3 nm bandwidth
Focuser: 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, ASCOM Platform
Processing: Pleiades Astrophoto PixInsight, MathWorks MATLAB, IHRP Platform