HD 149026 b

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Exoplanet
HD 149026 b (Smetrios)

Size comparison of HD 149026 b with Neptune and Jupiter

Size comparison of HD 149026 b with Neptune and Jupiter
Constellation Hercules
Position
equinox : J2000.0
Right ascension 16h 30m 29.618s
declination + 38 ° 20 ′ 50.311 ″
Orbit data
Central star HD 149026
Major semi-axis 0.043 AU
eccentricity 0.0
Period of circulation 2,876 d
Further data
radius 0.718 ± 0.065 R J
Dimensions 0.357   +0.014−0.011 M J
distance 76 pc
Discovery method Radial velocity method
Orbit inclination 85.3 ± 0.8 °
history
discovery Sato et al.
Date of discovery 2005
Catalog names
HD 149026 b, Smetrios, Ogma b

HD 149026 b ( Smertrios ) is an exoplanet in the constellation Hercules . The gas planet belongs to the class of Hot Jupiter , but is only about the size of the planet Saturn . Its mass is about 100 times the mass of the earth and it orbits the star HD 149026 (Ogma) , which is about 250  light years away . Its distance to this is very small, it only needs three earth days for one revolution .

Surface temperature

On the side facing its sun, it has a temperature of an estimated 2000 degrees Celsius . HD 149026 b is thus one of the hottest known exoplanets and even hotter than some low-mass stars.

According to the assumptions of the scientists who discovered the phenomenon, the cause of this heating up, which has never been observed in planets, may be that HD 149026 b reflects almost no starlight , but converts the light energy into infrared radiation ( heat radiation ) in a manner that was previously inexplicable radiates again immediately. On its surface, the heat does not seem to be distributed by winds , so the night side should be much colder. From this heat absorption capacity it is concluded that it is also the smallest and densest known planet with the darkest known surface (blacker than coal ).

According to another theory, previously unknown processes in the planet's atmosphere play an important role; there may be a connection with gaseous titanium or vanadium compounds , which occur in higher concentrations in it. HD 149026 b contains more heavy elements than our entire solar system with the exception of the sun itself. The existence of a heat source inside the planet is also considered.

The temperature was based on measurement data of the infrared - Telescope satellite Spitzer by a team of University of Central Florida in Orlando to the astronomer Joseph Harrington calculated. Since the orbit of the exoplanet from Earth is such that it regularly disappears and appears behind its star (see planetary transit ), the temperature could be approximately determined from the measurement differences in brightness (see transit method ). The result was published in the May 2007 issue of the science magazine Nature .

Origin of name

In addition to its systematic designation HD 149026 b, the exoplanet received the proper name Smertrios after the Celtic deity Smertrios after a public competition of the International Astronomical Union (IAU) on December 15, 2015 .

Web links

Commons : HD 149026b  - Collection of images, videos and audio files

Individual evidence

  1. ↑ HD 149026b. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on January 13, 2019 .
  2. ↑ a b c d e f g HD 149026. In: Extrasolar Planets Encyclopaedia . Retrieved January 13, 2019 .
  3. ↑ HD 149026. In: SIMBAD. Center de Données astronomiques de Strasbourg, accessed on January 13, 2019 .
  4. ↑ International Astronomical Union: NameExoWorlds - The Approved Names. Retrieved January 3, 2016 .