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| CH Cygni | |
|---|---|
| Name | CH Cygni |
| Constellation | Cygnus |
| Epoch | J2000 |
| Ra | 19h 24m 33s |
| Dec | +50° 14′ 29″ |
| Apparent magnitude | 5.6–11 |
| Spectral type | M6.5 III + accretion |
| Distance pc | 268 |
| Variable type | Symbiotic, Mira-like |
CH Cygni
CH Cygni is a symbiotic variable star system in the constellation Cygnus notable for alternating periods of optical brightness, radio activity, and X-ray emission. The system links observational programs associated with Harvard College Observatory, Royal Astronomical Society, Arecibo Observatory, Very Large Array, and space missions such as ROSAT and Chandra X-ray Observatory. Its study connects research traditions exemplified by Williamina Fleming, Annie Jump Cannon, Harlow Shapley, Walter Baade, and modern surveys like the Sloan Digital Sky Survey and Gaia (spacecraft).
CH Cygni comprises a cool red giant of spectral class M and a hot compact accretor, with properties studied by teams at National Optical Astronomy Observatory, European Southern Observatory, Keck Observatory, and Subaru Telescope. The red giant shows pulsations comparable to those cataloged by Henrietta Swan Leavitt and observed in surveys by All Sky Automated Survey and American Association of Variable Star Observers. The compact component has been interpreted within frameworks developed for white dwarfs, neutron stars, and stellar-mass black hole candidates, invoking accretion-disk models used in work by Frank, King and Raine and by observers at Mount Wilson Observatory.
The optical and infrared light curves display long-term activity similar to secular changes cataloged in studies by Eugène Joseph Delporte and modern light-curve analyses from Kepler (spacecraft), Transiting Exoplanet Survey Satellite, and Hipparcos. Photometric campaigns coordinated through American Association of Variable Star Observers, Variable Star Section of the British Astronomical Association, and projects associated with Palomar Observatory and Las Cumbres Observatory revealed quasi-periodic pulsations and outbursts analogous to those in classical symbiotics monitored by Mikołaj Kopernik–era catalogs and later by Heinrich Olbers-inspired variable catalogs. Correlations between optical dips, radio flares, and X-ray peaks have been compared to phenomena in SS 433, RS Ophiuchi, and T Coronae Borealis.
Spectroscopy from instruments on Hubble Space Telescope, Keck Observatory, Very Large Telescope, and William Herschel Telescope shows molecular bands characteristic of late-type giants and emission lines similar to those analyzed by Fritz Zwicky and Vera Rubin in other interacting binaries. Emission features include Balmer lines studied in the tradition of Giacomo Beccaria and forbidden lines whose diagnostics use techniques from Nicolaus Copernicus-inspired spectroscopy and from work by Walter Baade and Adriaan Blaauw. Abundance analyses reference methods developed by Hans Suess and Urey (scientist), while ultraviolet lines have been interpreted using models from Brian Schmidt and Adam Riess-era spectral synthesis.
CH Cygni exhibits collimated jets and episodic outflows resolved in radio and optical imaging by Very Large Array, Hubble Space Telescope, European VLBI Network, and MERLIN. Morphologies resemble jets in M87 and microquasar outflows in SS 433, with kinematics analyzed using interferometric techniques developed at Max Planck Institute for Radio Astronomy and instruments like Atacama Large Millimeter/submillimeter Array. Dust and molecular envelopes studied with facilities such as Spitzer Space Telescope, Infrared Space Observatory, and James Clerk Maxwell Telescope show complex circumbinary structures comparable to those around VY Canis Majoris and R Coronae Borealis.
Orbital solutions derived from radial-velocity work at Cerro Tololo Inter-American Observatory, McDonald Observatory, and Lick Observatory propose long-period orbits with possible triple-star configurations, echoing analysis methods used for systems like U Cephei and Algol. Dynamical studies reference techniques advanced by Jan Oort, Bertil Lindblad, and recent modelers at Institute of Astronomy, Cambridge and Harvard–Smithsonian Center for Astrophysics. Mass transfer, Roche-lobe considerations, and wind accretion draw on frameworks developed in studies of Cataclysmic variable stars and symbiotic binaries such as AG Draconis.
CH Cygni entered the variable-star record in the 20th century and has been the subject of campaigns by American Association of Variable Star Observers, researchers at Yerkes Observatory, and space-borne observers on ROSAT and Chandra X-ray Observatory. Major outbursts in the 1970s–1990s were reported in circulars from International Astronomical Union and analyzed in journals like Monthly Notices of the Royal Astronomical Society, Astrophysical Journal, and Astronomy & Astrophysics. Observational milestones involved collaborations spanning Smithsonian Astrophysical Observatory, Jet Propulsion Laboratory, and university groups at University of Cambridge, University of California, Berkeley, and University of Tokyo.
Category:Symbiotic stars Category:Stars in Cygnus