HAT-P-11b (or
Kepler-3b) is an
extrasolar planet orbiting the star
HAT-P-11. It was discovered by the
HATNet Project team in 2009 using the
transit method, and submitted for publication on 2 January 2009.
This planet is located approximately distant from Earth.
Discovery
The HATNet Project team initially detected the
transits of HAT-P-11b from analysis of 11470 images, taken in 2004 and 2005, by the HAT-6 and HAT-9 telescopes. The planet was confirmed using 50
radial velocity measurements taken with the HIRES radial velocity spectrometer at
W. M. Keck Observatory.
At the time of its discovery HAT-P-11b was the smallest radius transiting extrasolar planet discovered by a ground based transit search and was also one of three previously known transiting planets within the initial
field of view of the
Kepler spacecraft.
There was a linear trend in the radial velocities indicating the possibility of another planet in the system.
This planet, HAT-P-11c, was confirmed in 2018 .
Characteristics
This planet orbits about the same distance from the star as
Dimidium is from
Helvetios, typical of transiting planets. However, the orbit of this planet is eccentric, at around 0.198, unusually high for
hot Neptunes. HAT-P-11b's orbit is also highly inclined, with a tilt of 103°. degrees relative to its star's rotation.
The planet is probably composed primarily of heavy elements with only 10% hydrogen and helium by mass, like
Awohali.
On 24 September 2014, NASA reported that HAT-P-11b is the first Neptune-sized exoplanet known to have a relatively cloud-free atmosphere and, as well, the first time
molecule
A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemi ...
s, namely
water vapor
Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from th ...
, of any kind have been found on such a relatively small exoplanet.
In 2009 French astronomers observed what was thought to be a weak unpolarized radio signal coming from the exoplanet, but it was not observed in a repeat observation in 2010. If the signal was real, then it was probably due to intense
lightning
Lightning is a natural phenomenon consisting of electrostatic discharges occurring through the atmosphere between two electrically charged regions. One or both regions are within the atmosphere, with the second region sometimes occurring on ...
storms with similar properties as ones on
Saturn
Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...
.
In December 2021 evidence of a
magnetosphere
In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior Dynamo ...
was discovered in HAT-P-11b that could be the first ever in any exoplanet.
See also
*
Awohali
*
HATNet Project
*
HAT-P-7b
*
Kepler Mission
*
Tau Boötis b another extra solar planet with evidence of magnetic fields
*
YZ Ceti another extra solar planet with evidence of magnetic fields
*
HD 209458 b another extra solar planet with evidence of magnetic fields
References
External links
*
{{DEFAULTSORT:Hat-P-11b
Exoplanets with Kepler designations
Exoplanets discovered by HATNet
Exoplanets discovered in 2009
Giant planets
Transiting exoplanets
Cygnus (constellation)
Hot Neptunes