Iota Draconis b
Discovery | |
---|---|
Discovered by | Frink et al. |
Discovery date | January 8, 2002 |
Doppler Spectroscopy | |
Orbital characteristics | |
1.275 (± 0.074) AU | |
Eccentricity | 0.7124 (± 0.0039) |
511.098 (± 0.089) d 1.4 y | |
2,452,014.59 (± 0.30) | |
91.58 (± 0.81) | |
Semi-amplitude | 307.6 (± 2.3) |
Star | Iota Draconis |
Physical characteristics | |
Mean radius | ~12 REarth |
Mass | 8.82 ± 0.72 MJ |
Temperature | 598 K (325 °C; 617 °F) |
Iota Draconis b, formally named Hypatia (pronounced /haɪˈpeɪʃiə/ or /hɪˈpeɪʃə/), is an exoplanet orbiting the K-type giant star Iota Draconis about 101.2 light-years (31 parsecs, or nearly 2.932×1014 km) from Earth in the constellation Draco. The exoplanet was found by using the radial velocity method, from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star. It was the first planet discovered orbiting a giant star.[2]
Physical characteristics[]
Mass, radius and temperature[]
Iota Draconis b is a "super-Jupiter" a planet that has mass larger than that of the gas giants Jupiter and Saturn. It has a blackbody temperature of 598 K (325 °C; 617 °F). It has an estimated mass of around 8.82 MJ and a potential radius of around 12 REarth based on its mass, since it is more massive than Jupiter.
Host star[]
The planet orbits a (K-type) giant star named 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, Iota Draconis was probably a Class A star with surface temperature between 7,400 and 10,000K.[3] In comparison, the Sun is about 4.6 billion years old[4] and has a surface temperature of 5778 K.[5]
The star's apparent magnitude, a measure of how bright it appears from Earth, is 3.31. Therefore, Iota Draconis 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 AU (compared to Mars' orbital distance from the Sun, which is 1.52 AU) It has a very eccentric orbit, with an eccentricity of 0.7124.
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.[6] The process involved public nomination and voting for the new names.[7] In December 2015, the IAU announced that the winning name for this planet was Hypatia.[8] 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.[9]
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.[2]
References[]
- ^ Butler, R. P.; Wright, J. T.; Marcy, G. W.; Fischer, D. A.; Vogt, S. S.; Tinney, C. G.; Jones, H. R. A.; Carter, B. D.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701.
- ^ a b Frink; Mitchell, David S.; Quirrenbach, Andreas; Fischer, Debra A.; Marcy, Geoffrey W.; Butler, R. Paul (2002). "Discovery of a Substellar Companion to the K2 III Giant Iota Draconis". The Astrophysical Journal. 576 (1): 478–484. Bibcode:2002ApJ...576..478F. CiteSeerX 10.1.1.6.5332. doi:10.1086/341629.
- ^ Safonova, M.; Murthy, J.; Shchekinov, Yu. A. (2014). "Age Aspects of Habitability". International Journal of Astrobiology. 15 (2): 93–105. arXiv:1404.0641. Bibcode:2016IJAsB..15...93S. doi:10.1017/S1473550415000208.
- ^ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 19 February 2011.
- ^ Fraser Cain (September 15, 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011.
- ^ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
- ^ NameExoWorlds The Process
- ^ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
- ^ NameExoWorlds The Approved Names
External links[]
Coordinates: 15h 24m 55.7747s, +58° 57′ 57.836″
- Draco (constellation)
- Giant planets
- Exoplanets discovered in 2002
- Exoplanets detected by radial velocity
- Exoplanets with proper names