Iota Draconis b

Coordinates: Sky map 15h 24m 55.7747s, +58° 57′ 57.836″
Source: Wikipedia, the free encyclopedia.
Iota Draconis b
a (510.854 ± 0.013 d)
Inclination46+27
−19
87+64
−60
2455590.17±0.13
89.90±0.30
Semi-amplitude307.6 (± 2.3)
StarIota Draconis
Physical characteristics
Mass16.4+9.3
−4.0 MJ[2]

Iota Draconis b, formally named Hypatia (pronounced

Doppler shifts in the spectrum of the planet's parent star. It was the first planet discovered orbiting a giant star.[3]

Physical characteristics

Mass

Iota Draconis b is a "super-Jupiter", a planet that has mass larger than that of the gas giants Jupiter and Saturn. It has an estimated minimum mass of around 11.82 MJ.[2]

In 2021, astrometric observations revealed the true mass of Iota Draconis b to be 16.4 MJ.[2]

Host star

Main article: Iota Draconis

The planet orbits a (K-type) giant star named Edasich (designated Iota Draconis). The star has exhausted the hydrogen supply in its core and is currently fusing helium. The star has a mass of 1.82 M☉ and a radius of around 12 R☉. It has a surface temperature of 4545 K and is around 800 million years old based on its evolution. Although much younger than the Sun, the higher mass of this star correlates to a faster evolution, leading to the host star having already departed from the main sequence. When on the main sequence, Edasich was probably a Class A star with surface temperature between 7,400 and 10,000K.[4] In comparison, the Sun is about 4.6 billion years old[5] and has a surface temperature of 5778 K.[6]

The star's apparent magnitude, a measure of how bright it appears from Earth, is 3.31. Therefore, Edasich can be seen with the naked eye.

Orbit

Iota Draconis b orbits its star with nearly 55 times the Sun's luminosity (55 L☉) every 511 days at an average distance of 1.275

eccentric
orbit, with an eccentricity of 0.7124.

Discovery

Discovered in 2002 during a radial velocity study of K-class giant stars, its eccentric orbit aided its detection, as giant stars have pulsations which can mimic the presence of a planet.[3]

Name

Following its discovery the planet was designated Iota Draconis b. In July 2014, the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.[7] The process involved public nomination and voting for the new names.[8] In December 2015, the IAU announced that the winning name for this planet was Hypatia.[9] The winning name was submitted by Hypatia, a student society of the Physics Faculty of the Universidad Complutense de Madrid, Spain. Hypatia was a famous Greek astronomer, mathematician, and philosopher.[10]

References

  1. S2CID 119067572. Archived from the original
    on 2019-12-07. Retrieved 2009-03-11.
  2. ^
    S2CID 236493583
  3. ^
    S2CID 12778096
    .
  4. S2CID 20205600
    .
  5. ^ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 19 February 2011.
  6. ^ Fraser Cain (September 15, 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011.
  7. ^ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
  8. ^ "NameExoWorlds The Process". Archived from the original on 2015-08-15. Retrieved 2015-09-05.
  9. ^ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
  10. ^ "NameExoWorlds The Approved Names". Archived from the original on 2018-02-01. Retrieved 2016-01-02.

External links


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