HD 189733

Bonn survey	BD + 22 ° 3887
Henry Draper Catalog	HD 189733 [1]
Gliese catalog	FY 4130 [2]
Hipparcos catalog	HIP 98505 [3]
SAO catalog	SAO 88060 [4]
Tycho catalog	TYC 2141-972-1 [5]
2MASS catalog	2MASS J20004370 + 2242391 [6]
Other names	V452 Vulpeculae • Wolf 864 • LTT 15851 • GSC 02141-00972 • PPM 110211 • USNO-B1.0 1127-00538857

annotation

↑ Estimated from apparent brightness and distance.

HD 189733 is a main sequence star of spectral class K at a distance of 64 light years . It is located in the constellation Vulpecula and is orbited by at least one planet, HD 189733 b . The star has a surface radiation temperature of around 5050 degrees Celsius.

HD 189733 b

HD 189733 b is the only known planet of this system so far and belongs to the class of "hot gas giants" ( Hot Jupiter ). He has about 1.15 times the mass of the planet Jupiter and is only 4.7 million kilometers (that only 8 percent of the distance Mercury - Sun ) from its star, it orbits in about 2.22 days. Due to the strong tidal forces of the central star, HD 189733 b always turns the same side to it.

This is what HD 189733 b could look like: An artist's idea of the exoplanet

Hardly any other exoplanet is known as much as about HD 189733 b, which is due to the fact that the planet - seen from Earth - regularly passes in front of its star, i.e. the planet is a so-called transit planet . If the star's light travels through the planet's atmosphere on its way to Earth, the spectrum of the starlight changes according to the compounds in the planet's atmosphere, and so observation with the IR spectrometer Nicmos ( Near Infrared Camera and Multi-Object Spectrometer ) of the Spitzer Space Telescope found a lower absorption in the infrared band of 3.6 micrometers than expected during a transit , which can only be explained by the simultaneous presence of water and methane molecules in the planet's atmosphere.

HD 189733 b is therefore the first planet outside our solar system ( exoplanet ) on which water and methane - and thus an organic compound - were found, although the water is in a gaseous state due to the planet's high surface temperature of around 900 degrees Celsius. These results from the Spitzer telescope have now been confirmed by the Hubble space telescope .

On April 25, 2012, the camera and a spectrometer on board the Cassini space probe , which orbits the ring planet Saturn , observed another passage of the exoplanet in front of its star. The star's drop in brightness of around 2.5 percent could be captured particularly well with the camera. However, it was not possible to obtain a spectrum of the planet's atmosphere because the sensitivity of the spectrometer was insufficient.

Web links

Commons : HD 189733 - Collection of images, videos and audio files

ESA
The exoplanet in the "Encyclopedia of Extrasolar Planets"
Christian Weber: Another blue planet ; Süddeutsche Zeitung from July 12, 2013

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g ^h HD 189733. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on January 13, 2019 .
^ Hipparcos catalog (ESA 1997)
↑ ^a ^b ^c ^d HD 189733. In: NASA Exoplanet Archive . Retrieved January 13, 2019 .
↑ Mark R. Swain: Nature, vol. 452, p . 329 . NPG, 2008.

↑ Organic molecules discovered on a distant planet. Spiegel Online, March 20, 2008, accessed March 20, 2008 .

^ Astronomers Detect First Organic Molecule on an Exoplanet. Jet Propulsion Laboratory, March 19, 2008, accessed March 20, 2008 .

↑ HD 189733b: Hubble finds organic molecules. extrasolar-planets, March 20, 2008, accessed March 20, 2008 .

[ber-3] Estimated from apparent brightness and distance.

[Simbad-1] ↑ ^a ^b ^c ^d ^e ^f ^g ^h HD 189733. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on January 13, 2019 .

[hip1-2] Hipparcos catalog (ESA 1997)

[Nasa-4] HD 189733. In: NASA Exoplanet Archive . Retrieved January 13, 2019 .

[5] Mark R. Swain: Nature, vol. 452, p . 329 . NPG, 2008.

[6] Organic molecules discovered on a distant planet. Spiegel Online, March 20, 2008, accessed March 20, 2008 .

[7] Astronomers Detect First Organic Molecule on an Exoplanet. Jet Propulsion Laboratory, March 19, 2008, accessed March 20, 2008 .

[8] HD 189733b: Hubble finds organic molecules. extrasolar-planets, March 20, 2008, accessed March 20, 2008 .