Eurystheus

Eurystheus (, P163) is an which orbits the yellow-orange   , meaning the star is smaller, cooler and thus dimmer than our. It is approximately 57 s or 18 s from towards the   in the caelregio Tarandus.

Eurystheus is a several times more massive than Jupiter and orbits further from the star than Jupiter is to the Sun.

is named after the king of, one of three strongholds in the  in.

Discovery and chronology
Eurystheus was discovered on November 17, 2005 by a team of astronomers led by. The team used the mounted on the telescope in  in Texas and found that this star has a long-term trend in addition to the inner planet Cerenytis discovered seven years prior. Less than a year later on November 2, 2006, Eurystheus was confirmed.

Eurystheus is the 156$J$ exoplanet discovered overall, 130$J$ since 2000, and 35$J$ in 2005. Eurystheus is the 3$J$ exoplanet discovered in the constellation Hercules (2$J$ in 2005) and 13$J$ in the caelregio Tarandus (4$⊕$ in 2005). Since Eurystheus is the second planet discovered in the 14 Herculis system, the planet receives the designations 14 Herculis c (a is not used because the parent star uses this letter to reduce confusion) and 14 Herculis P2. Note that the chronology does not include speculative s (objects with minimum masses below 13 M$⊕$ but with speculative true masses above 13 M$⊕$).

Orbit
Eurystheus is located near the middle of the Jovian orbit (which is a classification of orbit) as it orbits the star at an of 6.86  (1 AU is the average distance between the Earth and the Sun). If we place this planet in our solar system, it would orbit between the orbits of and. Eurystheus has an almost perfectly circular orbit with an eccentricity of 0.004. Despite the Eurystheus' wide orbit, the orbital distance can only vary by about 0.06 AU from the star. The planet takes 18.91 years or nearly 227 months to make one complete trip around the star at an of 2.28 AU/yr or 10.8 km/s. Eurystheus is in a 4:1 with the inner known planet Cerenytis.

Parent star observation and irradiance
Viewed from Eurystheus, the parent star would appear to be 83 times fainter than the Sun seen from Earth. The parent star has a −21.95 compared to −26.74 for the Sun's magnitude viewed from Earth. Viewed from Eurystheus, the parent star would have an of 4.2' on average, which is  the angular diameter of the  we see every month.

Eurystheus receives 17 watts worth of energy per square meter from the parent star compared 1368 W/m² for Earth.

Rotation
Eurystheus rotates very rapidly, even more rapid than the fastest rotator in the solar system, Jupiter. It takes just 8.2 hours to make one complete turn, similar to the period of Cerenytis. A year on Eurystheus lasts 20181 Eurystheus days, which is 55.10 times longer than a year on Earth. Even more stranger is that the planet rotates on its side like. The planet tilts 80.8° to the plane of its orbit, which is almost perpendicular to its orbit. The planet's points to the constellation  (in Avis), while the  points to the constellation  (in Malus).

Mass and size
Eurystheus is massive, 4.68 times more massive than Jupiter, the most massive planet in our solar system. It is classified as super-Jupiter in the planetary mass classification scheme. Even though this planet is much more massive than Jupiter, it is slightly smaller than Jupiter, meaning that Eurystheus must be very dense, has very strong gravity, and has very high. Even though Eurystheus is denser than Earth (6.8 vs. 5.5 g/cm³), the densest planet in our solar system, it would still be a with no solid surface.

This planet is more spherical than any giant planet in our solar system with a flattening of 0.01747. The equatorial radius is 68,258 km while the polar radius is 67,073 km. Using these three datas, its mean radius is calculated to be 67,863 km, actually twice as close to its equatorial radius than its polar radius.

Gravitational influence
The gravitational force of Eurystheus is over 13 times stronger than Earth's. So if you weigh 150 on Earth, you would weigh 1967 pounds or almost a  on Eurystheus. So a person standing on Eurystheus would weigh nearly as much as a small car parked on Earth! To escape this planet, it would need to go more than twice as fast as required to escape Jupiter and 12 times faster than is required to escape Earth.

Since the gravity of this planet is so strong, the lies relatively far from the planet at 1.65 planetary radii. Eurystheus has a very large, with its boundary lying at 1850 times the radius of the planet or 327. The lies nearly 60% further out than roche limit. The orbital velocity at stationary orbit is calculated to be 50.2 km/s or 31.2 mi/s. Since the planet takes 8.2 hours to rotate, then a moon would also take 8.2 hours to orbit the planet at stationary orbit.

Interior
Below Eurystheus' outer envelope (atmosphere), the weight of all the gases pressing down produce a tremendous pressure. That pressure allow and  to condense in the upper mantle despite the higher temperatures deeper down. In the middle mantle lies liquid where hydrogen can conduct electricity under even greater pressure heated beyond its. In the lower mantle, there is narrow layer of solid metallic hydrogen. At the center lies an ultra-dense core of rock and metal with a mass 86 Earth masses, roughly 5.8% the total mass of the planet. The temperature of the core is estimated to be 113,400 K (113,100°C, 203,700°F) and an estimated pressure 489.

Atmosphere
Like all gas giants, Eurystheus' atmosphere composes mostly of (92%), with  (5.8%) and  (2.8%) making up most of the rest. Eurystheus contains trace amounts of other gases, including and. makes up 43 of the atmosphere. Unlike most gas giants and common on s, the atmosphere contains but at a concentration of 2.

Eurystheus contains banded clouds of ammonia and water and this planet would appear as orange and white stripes from space. The ammonia clouds are in the cooler upper deck and water clouds in the warmer lower deck. The temperature of this planet is 239 K (−34°C, −30°F), which is far warmer than its of 85 K (−188°C, −307°F) due to its high mass and density that produces a lot of. This planet radiates four times the amount of energy than it receives from the parent star. There are thousands of s and s, which can produce violent long-lasting storms and high winds, even more violent than Jupiter's.

Magnetic field
This planet has a very strong, about 7.83 , which is 25 times stronger than.

That powerful magnetic field is produced by the movements of metallic hydrogen in its interior caused by the planet's rotation. This mechanism is well known as. The magnetic field blocks most of stellar and from reaching the planet, but occasionally it can produce beautiful, vivid e when the stellar radiation got caught in the magnetic field lines and move towards their  where it interact with the planet's upper atmosphere. Its magnetic field is so strong that occasional auroral display are often more brilliant than aurorae on Earth.

Moons and rings
Eurystheus has a big family of 148, several of them larger than our. The largest moon has mass 23.7 es (0.291 Earth masses) and has diameter 2.871 D$2$ (6,198 miles, 9,974 kilometers). There are six moons bigger than our Moon and one of these is larger than Mars. 14 moons have diameters between 1000 miles and 2000 miles, 49 have diameters between 100 and 1000 miles and 79 have diameters less than 100 miles.

Eurystheus has 23. The rings are made mainly of dusts and boulders, and little ice.

Future studies
The probability that Eurystheus will 14 Herculis can be a slim 0.29% chance, but it is speculated that Eurystheus will not transit since I speculated that the  is 27°. Eurystheus can be studied effectively using or. The planet can be studied using astrometry using, (JWST),  (SIM), or even the current  (HST) guidance sensor. The astrometry can constrain the inclination and thus calculate the exact mass. The direct imaging can see what the planet may really look like. The direct imaging can constrain the size of this planet like. The derivative parameters, including density and surface gravity, can then be calculated using the radius constrained from transit and true mass calculated by inclination. Using the calculated density, astronomers can model the interior of this planet.

Astronomers may eventually use to study the interior, including the extent, features and compositions by layers. Using the mounted on the JWST, the atmosphere can be studied, including temperatures, chemical makeup, and features. Using the same method, the rotation rate can be constrained using s, which in turn can then be calculated.

In orbit around the planet, moons can be detected using the transit across the planet, detecting the wobble of the planet, or even direct imaging. Rings can also be detected using just two methods: transit or direct imaging.

Eurystheus can further be studied using the JWST's successor:, due to launch between 2025–35.

Related links

 * Cerenytis (14 Herculis b, P20)