![]() Size comparison of HAT-P-1b with Jupiter. | |
Discovery | |
---|---|
Discovered by | HATNet Project [1] |
Discovery site | Arizona and Hawaii [1] |
Discovery date | Thurs, Sept 14, 2006 [2] |
Transit, radial velocity [1] | |
Orbital characteristics | |
0.05561 ± 0.00083 AU (8,319,000 ± 124,000 km) [3] | |
Eccentricity | <0.067 [4] |
4.4652968 ± 0.0000018 [5] d | |
Inclination | 85.634 ± 0.056 [3] |
Semi-amplitude | 59.3 ± 1.4 [4] |
Star | HAT-P-1 (ADS 16402 B) |
Physical characteristics | |
1.319 ± 0.019 [3] RJ | |
Mass | 0.529 ± 0.020 [5] MJ |
Temperature | 1322 ± 15 [3] K |
HAT-P-1b is an extrasolar planet orbiting the Sun-like star HAT-P-1, also known as ADS 16402 B. HAT-P-1 is the dimmer component of the ADS 16402 binary star system. It is located roughly 521 light years away from Earth in the constellation Lacerta. HAT-P-1b is among the least dense of any of the known extrasolar planets.
HAT-P-1b was detected by searching for astronomical transits of the parent star by orbiting planets. As the planet passes in front of its parent star (as seen from Earth), it blocks a small amount of the light reaching us from the star. HAT-P-1b was first detected by a dip of 0.6% in the light from the star. This enabled determination of the planet's radius and orbital period. The discovery was made by the HATNet Project (Hungarian Automated Telescope Network) using telescopes at the Fred Lawrence Whipple Observatory on Mount Hopkins in Arizona and at the Submillimeter Array facility in Hawaii. It was confirmed and the orbital parameters determined by radial velocity measurements made at the 8.2 m Subaru and 10 m Keck telescopes, the discovery announcement being made on September 14, 2006. [2] [1]
HAT-P-1b is located in a very close orbit to its star, taking only 4.47 days to complete. [1] It therefore falls into the category of hot Jupiters. At only 8.27 million kilometers from the star, tidal forces would circularise the orbit unless another perturbing body exists in the system. At the present time, the existing measurements are not sufficient to determine the orbital eccentricity, so a perfectly circular orbit has been assumed by the discoverers. [6] However, the eccentricity of the planet was calculated to be no greater than 0.067.
In order to determine the mass of the planet, measurements of the star's radial velocity variations were made by the N2K Consortium. This was done by observing the Doppler shift in the star's spectrum. Combined with the known inclination of the orbit as determined by the transit observations, this revealed the mass of the planet to be 0.53±0.04 times that of Jupiter. [1]
As of August 2008, the most recent calculation of HAT-P-1b's Rossiter–McLaughlin effect and so spin-orbit angle was 3.7±2.1°. [7]
As evidenced by its high mass and planetary radius, HAT-P-1b is a gas giant, most likely composed primarily of hydrogen and helium. The emission from C2, CN and CH radicals in planetary atmosphere was detected in 2022. [8] The planetary atmosphere is hazy rather than cloudy, with observed clouds area fraction 22+5
−3 percent. [9]
Current theories predict that such planets formed in the outer regions of their solar systems and migrated inwards to their present orbits.
HAT-P-1b is significantly larger than predicted by theoretical models. [2] This may indicate the presence of an additional source of heat within the planet. One possible candidate is tidal heating from an eccentric orbit, a possibility which has not been ruled out from the available measurements. [10] However, another planet with a significantly inflated radius, HD 209458 b, is in a circular orbit.
An alternative possibility is that the planet has a high axial tilt, like Uranus in the Solar System. The problem with this explanation is that it is thought to be quite difficult to get a planet into this configuration, so having two such planets among the set of known transiting planets is problematic.
HD 209458 b is an exoplanet that orbits the solar analog HD 209458 in the constellation Pegasus, some 157 light-years from the Solar System. The radius of the planet's orbit is 0.047 AU, or one-eighth the radius of Mercury's orbit. This small radius results in a year that is 3.5 Earth-days long and an estimated surface temperature of about 1,000 °C. Its mass is 220 times that of Earth and its volume is some 2.5 times greater than that of Jupiter. The high mass and volume of HD 209458 b indicate that it is a gas giant.
TrES-1b is an extrasolar planet approximately 523 light-years away in the constellation of Lyra. The planet's mass and radius indicate that it is a Jovian planet with a similar bulk composition to Jupiter. Unlike Jupiter, but similar to many other planets detected around other stars, TrES-1 is located very close to its star, and belongs to the class of planets known as hot Jupiters. The planet was discovered orbiting around GSC 02652-01324.
Hot Jupiters are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital periods. The close proximity to their stars and high surface-atmosphere temperatures resulted in their informal name "hot Jupiters".
HD 149026 b, formally named Smertrios, is an extrasolar planet and hot Jupiter approximately 250 light-years from the Sun in the constellation of Hercules. HD 149026, also named Ogma,
HD 147506, also known as HAT-P-2 and formally named Hunor, is a magnitude 8.7 F8 dwarf star that is somewhat larger and hotter than the Sun. The star is approximately 419 light-years from Earth and is positioned near the keystone of Hercules. It is estimated to be 2 to 3 billion years old, towards the end of its main sequence life. There is one known transiting exoplanet, and a second planet not observed to transit.
HAT-P-2b is an extrasolar planet detected by the HATNet Project in May 2007. It orbits a class F star HAT-P-2,, located about 420 light-years away in the constellation Hercules.
The Hungarian Automated Telescope Network (HATNet) project is a network of six small fully automated "HAT" telescopes. The scientific goal of the project is to detect and characterize extrasolar planets using the transit method. This network is used also to find and follow bright variable stars. The network is maintained by the Center for Astrophysics | Harvard & Smithsonian.
XO-3b is an exoplanet with about 11.79 times the mass of Jupiter, and it orbits its parent star XO-3 in about 3.2 days. The radius of this object is 1.217 times that of Jupiter. Astronomers announced their discovery on May 30, 2007, at the American Astronomical Society in Honolulu, Hawaii. Its discovery is attributed to the combined effort of amateur and professional astronomers working together on the XO Project using a telescope located on the Haleakala summit in Hawaii.
HAT-P-4b is a confirmed extrasolar planet orbiting the star HAT-P-4 over 1000 light years away in Boötes constellation. It was discovered by transit on October 2, 2007, which looks for slight dimming of stars caused by planets that passed in front of them. It is the fourth planet discovered by the HATNet Project. It is also called BD+36 2593b, TYC 2569-01599-1b, 2MASS J15195792+3613467b, SAO 64638b.
ADS 16402 is a binary star system, composed of two sun-like stars located approximately 525 light-years away in the constellation Lacerta. It was first identified as a binary star by John Herschel in 1831. The two stars are separated by 11.26 arcseconds which leads to a projected separation of roughly 1500 astronomical units at the distance of ADS 16402. The star system is estimated to be 1.9 ± 0.6 billion years old. The secondary star ADS 16402 B is also designated HAT-P-1.
HAT-P-7b is an extrasolar planet discovered in 2008. It orbits very close to its host star and is larger and more massive than Jupiter. Due to the extreme heat that it receives from its star, the dayside temperature is predicted to be 2,630–2,880 K, while nightside temperatures are 2,211–2,238 K. HAT-P-7b is also one of the darkest planets ever observed, with an albedo of less than 0.03—meaning it absorbs more than 97% of the visible light that strikes it.
HAT-P-8b is an extrasolar planet located approximately 720 light years away in the constellation of Pegasus, orbiting the 10th magnitude star GSC 02757-01152. This planet was discovered by transit on December 5, 2008. Despite the designation as HAT-P-8b, it is the 11th planet discovered by the HATNet Project. The mass of the planet is 50% more than Jupiter while the radius is also 50% more than Jupiter. The mass of this planet is exact since the inclination of the orbit is known, typical for transiting planets. This is a so-called “hot Jupiter” because this Jupiter-like gas giant planet orbits in a really close torch orbit around the star, making this planet extremely hot. The distance from the star is roughly 20 times smaller than that of Earth from the Sun, which places the planet roughly 8 times closer to its star than Mercury is from the Sun. The “year” on this planet lasts only 3 days, 1 hour, 49 minutes, and 54 seconds, compared with Earth's 365 days, 6 hours, 9 minutes, and 10 seconds in a sidereal year.
HAT-P-11b 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.
WASP-17b, officially named Ditsö̀, is an exoplanet in the constellation Scorpius that is orbiting the star WASP-17. Its discovery was announced on 11 August 2009. It is the first planet discovered to have a retrograde orbit, meaning it orbits in a direction counter to the rotation of its host star. This discovery challenged traditional planetary formation theory. In terms of diameter, WASP-17b is one of the largest exoplanets discovered and at half Jupiter's mass, this made it the most puffy planet known in 2010. On 3 December 2013, scientists working with the Hubble Space Telescope reported detecting water in the exoplanet's atmosphere.
HAT-P-14b, officially named Sissi also known as WASP-27b, is an extrasolar planet located approximately 224.2 ± 0.6 parsecs (731.2 ± 2.0 ly) away in the constellation of Hercules, orbiting the 10th magnitude F-type main-sequence star HAT-P-14. This planet was discovered in 2010 by the HATNet Project using the transit method. It was independently detected by the SuperWASP project.
HAT-P-32b is a planet orbiting the G-type or F-type star HAT-P-32, which is approximately 950 light years away from Earth. HAT-P-32b was first recognized as a possible planet by the planet-searching HATNet Project in 2004, although difficulties in measuring its radial velocity prevented astronomers from verifying the planet until after three years of observation. The Blendanal program helped to rule out most of the alternatives that could explain what HAT-P-32b was, leading astronomers to determine that HAT-P-32b was most likely a planet. The discovery of HAT-P-32b and of HAT-P-33b was submitted to a journal on 6 June 2011.
HAT-P-24b is an extrasolar planet discovered by the HATNet Project in 2010 orbiting the F8 dwarf star HAT-P-24. It is a hot Jupiter, with a mass three quarters that of Jupiter and a radius 20% larger.
HAT-P-17 is a K-type main-sequence star about 92.4 parsecs (301 ly) away. It has a mass of about 0.857 ± 0.039 M☉. It is the host of two planets, HAT-P-17b and HAT-P-17c, both discovered in 2010. A search for a binary companion star using adaptive optics at the MMT Observatory was negative. A candidate companion was detected by a spectroscopic search of high-resolution K band infrared spectra taken at the Keck observatory.
The Next-Generation Transit Survey (NGTS) is a ground-based robotic search for exoplanets. The facility is located at Paranal Observatory in the Atacama Desert in northern Chile, about 2 km from ESO's Very Large Telescope and 0.5 km from the VISTA Survey Telescope. Science operations began in early 2015. The astronomical survey is managed by a consortium of seven European universities and other academic institutions from Chile, Germany, Switzerland, and the United Kingdom. Prototypes of the array were tested in 2009 and 2010 on La Palma, and from 2012 to 2014 at Geneva Observatory.
HAT-P-67 is a binary star system, made up of a F-type subgiant and a red dwarf star, which is located about 1,200 light-years away in the constellation Hercules. There is a hot Saturn planet orbiting the primary star, which is named HAT-P-67b.
Media related to HAT-P-1b at Wikimedia Commons