KELT-9b

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Exoplanet
KELT-9b

Artist's impression of HD 195689 (left) and its companion KELT-9b (not to scale)

Artist's impression of HD 195689 (left) and its companion KELT-9b (not to scale)
Constellation swan
Position
equinox : J2000.0
Right ascension 20h 31m 26.35s
declination + 39 ° 56 ′ 19.8 ″
Orbit data
Central star HD 195689 (KELT-9)
Major semi-axis 0.03462 +0.00110 −0.00093 AU
Period of circulation 1.4811235 ± 0.0000011 d
Further data
radius 1,891 +0.061 −0.053 R J
Dimensions 2.88 ± 0.84 M J
distance 200 pc
Inclination 86.79 (± 0.25) °
Medium density 530 ± 0.15 kg m −3
temperature 4050 ± 180 K
Apparent brightness 7.56 likes
history
Date of discovery 22nd June 2017

KELT-9b (or HD 195689b) is a Exoplanet in about 620 light years distance to the sun . It was discovered in 2017 by the Kilodegree Extremely Little Telescope (KELT) program. With a surface temperature of up to 4600 Kelvin (side facing the star), the celestial body is the hottest exoplanet known to date. This surface temperature corresponds to the many stars of spectral type K .

The planet meets all the requirements for being categorized as Hot Jupiter . KELT-9b orbits its hot central star HD 195689 ( R ☉ 1.58, spectral type A0 at 10,170 K) rotationally bound at the very short distance of only 0.034 AU . It only takes 1.48 days for this cycle. These conditions result in extremely high surface temperatures, especially on the side facing the star. This in turn leads to a volume that is above the expectations of the pure mass consideration and, accordingly, to a relatively low density . The upper layers of the extended atmosphere are permanently ablatively eroded by the UV radiation influence of the hot star , which leads to a tail-like loss of the strongly ionized atmospheric gases. According to Keivan Stassun, physics professor at Vanderbilt University , this development is likely to continue until KELT-9b has completely disappeared or, if it contains a rock core like many other gas giants, only this remains.

The responsible team succeeded in discovering and determining the radius of the gas giant by using the transit method , while the determination of the mass and the detection of various substances were carried out using spectral measurements .

Evidence of various atmospheric elements

A special feature of KELT-9b is the wide range of elements that could be detected by means of spectroscopic examination. The prevailing temperatures ensure that even relatively heavy metals in ionized form are part of the gas atmosphere.

Schematic representation of the transit of KELT-9b

In addition to sodium , chromium , magnesium and calcium , iron and titanium atoms could be detected on an exoplanet for the first time . The discovery of the rare earths yttrium and scandium is also a novelty.

Animation of the rotation-bound orbit by KELT-9b (tail formation due to high loss of atmospheric gases)
Animation of the star system around HD 195689

Web links

Individual evidence

  1. ↑ a b c https://keltsurvey.org/planets
  2. ↑ a b c d e f http://exoplanet.eu/catalog/hd_195689_b/
  3. ↑ Karen A. Collins, Keivan Stassun, B. Scott Gaudi, Thomas G. Beatty, George Zhou: KELT-9b: A Case Study in Dynamical Planet Ingestion by a Hot Host Star . In: DDA . May 2016, p. 204.03 ( harvard.edu [accessed January 24, 2020]).
  4. ↑ BS Gaudi et al .: A Giant Planet Undergoing Extreme-Ultraviolet Irradiation By Its Hot Massive-Star Host Hot Massive-Star Host. Swarthmore College Swarthmore College, June 22, 2017, accessed January 24, 2020 .
  5. ↑ KS Jensen: Spectral classification in the MK system of 167 northern HD stars. In: A&AS . tape 45 , September 1981, ISSN  0365-0138 , p. 455–458 ( harvard.edu [accessed January 24, 2020]).
  6. ↑ B. Scott Gaudi, Keivan G. Stassun, Karen A. Collins, Thomas G. Beatty, George Zhou: A giant planet undergoing extreme-ultraviolet irradiation by its hot massive star-host . In: Nature . tape 546 , no. 7659 , June 2017, ISSN  1476-4687 , p. 514-518 , doi : 10.1038 / nature22392 ( nature.com [accessed January 21, 2020]).
  7. ↑ Astronomers Find Planet Hotter Than Most Stars. Retrieved January 24, 2020 .
  8. ↑ Fei Yan, Thomas Henning: An extended hydrogen envelope of the extremely hot giant exoplanet KELT-9b . In: Nature Astronomy . tape 2 , no. 9 , September 2018, ISSN  2397-3366 , p. 714–718 , doi : 10.1038 / s41550-018-0503-3 ( nature.com [accessed January 24, 2020]).
  9. ↑ KELT-9b: Newly-Discovered 'Hot Jupiter' Hotter Than Most Stars | Astronomy | Sci-News.com. Retrieved January 24, 2020 (American English).
  10. ↑ MVS Import: Astronomers discover the hottest exoplanets . In: scinexx | The knowledge magazine . June 5, 2017 ( scinexx.de [accessed January 24, 2020]).
  11. ^ The Extrasolar Planet Encyclopaedia - HD 195689 b. Retrieved January 24, 2020 .
  12. ↑ For the first time traces of rare earths discovered on an exoplanet - derStandard.at. Retrieved January 24, 2020 (Austrian German).
  13. ↑ Lorenzo Pino, Jean-Michel Desert, Luca Malavolta, Francesco Borsa: Metals in the emission spectrum of Kelt-9b . In: ESS . tape 51 , August 2019, p. 326.21 ( harvard.edu [accessed January 24, 2020]).
  14. ↑ Patricio E. Cubillos, Luca Fossati, Tommi Koskinen, Mitchell E. Young, Michael Salz: Near-ultraviolet Transmission Spectroscopy of HD 209458b: Evidence of Ionized Iron Beyond the Planetary Roche Lobe . In: arXiv . January 2020, p. arXiv: 2001.03126 ( harvard.edu [accessed January 24, 2020]).
  15. ↑ Jake D. Turner, Ernst JW de Mooij, Ray Jayawardhana, Mitchell E. Young, Luca Fossati: Detection of Ionized Calcium in the Atmosphere of the Ultra-hot Jupiter KELT-9b . In: ApJL . tape 888 , no. January 1 , 2020, ISSN  0004-637X , p. L13 , doi : 10.3847 / 2041-8213 / ab60a9 ( harvard.edu [accessed January 24, 2020]).
  16. ↑ H. Jens Hoeijmakers, David Ehrenreich, Kevin Heng, Daniel Kitzmann, Simon L. Grimm: Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b . In: nature . tape 560 , no. 7719 , August 2018, ISSN  0028-0836 , p. 453–455 , doi : 10.1038 / s41586-018-0401-y ( harvard.edu [accessed January 24, 2020]).
  17. ↑ Lorenzo Pino, Jacob Arcangeli, Jacob L. Bean, Jean-Michel Desert, Jens Hoeijmakers: Measuring the first [Fe / H] of an exoplanet . In: hst . June 2019, p. 15820 ( harvard.edu [accessed January 24, 2020]).
  18. ^ Wiener Zeitung Online: Rare elements discovered in exoplanets for the first time. Retrieved January 24, 2020 .