HD 189733 b

HD 189733 b
Name	HD 189733 b
Discoverer	Michel Mayor; Didier Queloz; Geneva Observatory
Discovery site	Haute-Provence Observatory
Discovery date	2005
Star	HD 189733
Semimajor axis	0.031 AU
Orbital period	2.2 days
Mean radius	1.138 R_J
Mass	1.13 M_J
Eccentricity	~0
Inclination	~85.7°

HD 189733 b is a well-studied transiting exoplanet orbiting the K-type star HD 189733. It was among the earliest hot Jupiters characterized with transit spectroscopy and has been central to comparative studies involving Hubble Space Telescope, Spitzer Space Telescope, Kepler, and ground-based observatories. Research on this planet links to major figures and institutions in exoplanetology and to missions such as James Webb Space Telescope and Very Large Telescope.

Discovery and Observations

HD 189733 b was discovered in 2005 by a team including Michel Mayor and Didier Queloz using radial velocity measurements at the Haute-Provence Observatory and followed up with transit photometry at the W. M. Keck Observatory, European Southern Observatory, Calar Alto Observatory, and Nordic Optical Telescope. Early characterization involved spectrographs and photometers developed by groups at the Geneva Observatory, Observatoire de Haute Provence, and teams associated with NASA and European Space Agency. Subsequent observations have employed space platforms such as Hubble Space Telescope, Spitzer Space Telescope, Chandra X-ray Observatory, XMM-Newton, and planning studies for James Webb Space Telescope programs tied to institutions like NASA Ames Research Center and STScI.

Orbital and Physical Characteristics

HD 189733 b orbits at ≈0.031 AU from its parent star with an orbital period near 2.2 days and an inclination permitting deep transits measured by instruments at Palomar Observatory, La Silla Observatory, Mount Hopkins Observatory, and Cerro Tololo Inter-American Observatory. Mass and radius estimates derived from radial velocity work by teams at University of Geneva and transit fitting by researchers affiliated with Massachusetts Institute of Technology and University of California, Berkeley place it near Jupiter mass and radius, producing a bulk density comparable to inflated gas giants studied by groups at Cambridge University and Harvard University. The orbit is essentially circular, consistent with tidal circularization models explored in studies from Princeton University and Caltech.

Atmosphere and Composition

Atmospheric detection used transmission and emission spectroscopy with Hubble Space Telescope instruments like STIS and NICMOS, and infrared photometry and spectroscopy from Spitzer Space Telescope instruments such as IRAC and IRS. Analyses by teams at University College London, University of Exeter, University of Oxford, and Max Planck Institute for Astronomy reported water vapor, sodium, and high-altitude haze. Detections invoked models developed at University of Arizona and University of Chicago and compared to retrieval frameworks from Carnegie Institution for Science and Jet Propulsion Laboratory. Claims of methane and carbon monoxide were debated among groups at Caltech, University of California, Santa Cruz, and University of Grenoble-Alpes using comparative data from Keck Observatory and Very Large Telescope.

Weather and Climate Phenomena

Studies of day–night temperature contrasts, hot-spot offsets, and wind speeds used phase curve mapping from Spitzer Space Telescope and spectroscopic Doppler signatures measured by teams at Observatoire de Haute Provence, University of Oxford, and Leiden University. Interpretations employed general circulation models from University of Cambridge, Imperial College London, Princeton University, and University of Tokyo to explain supersonic winds, thermal inversions, and redistribution efficiency. Observations suggesting silicate or sulfur aerosol clouds linked research groups at Caltech, Max Planck Institute for Extraterrestrial Physics, ETH Zurich, and University of Colorado Boulder. Flare-driven variability and star–planet interactions were examined with X-ray observatories by scientists at Harvard-Smithsonian Center for Astrophysics, MIT, and Columbia University.

Host Star and System Context

The host, HD 189733, is a K-type main-sequence star cataloged and studied at Hipparcos and Gaia with stellar parameters refined by researchers at European Southern Observatory and University of Geneva. The system’s parallax and proper motion appear in catalogs maintained by ESA and analyses by Max Planck Institute for Astronomy. The stellar activity cycle, spot modulation, and chromospheric emission have been measured with facilities at Mount Wilson Observatory, Konkoly Observatory, and Siding Spring Observatory by teams including members from University of Sydney and Observatoire de Paris.

Scientific Significance and Studies

HD 189733 b has been a benchmark for atmospheric retrieval, cloud physics, and star–planet interaction studies spearheaded by consortia from NASA, ESA, UK Space Agency, and national observatories. Work on this object influenced atmospheric models at University of Exeter, chemical kinetics frameworks at University of Cambridge, and instrument concepts for James Webb Space Telescope, Ariel (spacecraft), and ground-based Extremely Large Telescope projects such as European Extremely Large Telescope and Thirty Meter Telescope. Collaborations involving Harvard University, Yale University, Stanford University, and University of Michigan have used HD 189733 b as a testbed for retrieval algorithms, 3D circulation code development, and data analysis standards propagated through organizations like American Astronomical Society.

Detection Techniques and Instrumentation

Key detection and follow-up techniques included radial velocity spectroscopy using instruments like ELODIE, HARPS, and HIRES at Keck, combined with transit photometry from Hubble Space Telescope and infrared photometry from Spitzer Space Telescope. High-dispersion spectroscopy and cross-correlation methods were applied with spectrographs at Very Large Telescope (CRIRES), Subaru Telescope (HDS), and Gemini Observatory by teams from University of Toronto, University of Edinburgh, and University of Cambridge. Polarimetric searches and secondary-eclipse measurements employed specialized instruments developed at Leiden University, Swiss Federal Institute of Technology in Zurich, and labs at Caltech and contributed to methodology adopted by missions like Ariel (spacecraft).

Category:Exoplanets