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Exoplanetary Scratchpad

[SysBP Img]

Copernicus is also known as Rho Cancri, 55 Cancri, Rho1 Cancri, HR 3522, Gl 324, and HD 75732. Wide binary star consisting of a sun-like primary (A, though super metal rich) and a red-dwarf secondary (B) separated by 1,100 AU, 41 light years away. Star A contains five exoplanets, the first system found with four or five planets. It has three tightly packed eccentric planets close in to the star, including planet Jannsen (e, hot Super Earth/Neptunian), Galileo (b, warm Jupiter), and Brahe (c, hot Saturn), followed by an eccentric Saturn in the habitable zone (Harriot, f) and a Jupiter analog, Lippershey (d). Planet e was heralded as the first Neptunian discovered. It was later found to be the shortest-period planet discovered (18 hours) and to transit. Its density was measured and determined to be rocky, and thus re-dubbed the first Super-Earth discovered. It was then the first super-Earth to have its light detected (by Spitzer in the infrared). The planet has about half of Neptune's mass, but is Earth-like in size and density (2.17 Earth Radius). Studies taking into account the composition of the star suggested that it was largely made of diamond, with graphite at the surface (the first diamond planet around a Sunlike star), and the first terrestrial found with fundamentally different surface composition and processes than Earth. This was later refuted when it turned out there wasn't as much carbon in the parent star as believed. Earlier studies that assumed an Earth-like composition suggested that it would be covered with an ocean of super-critical water. The brightness of the planet was found to have raised dramatically, possibly the aftermath of cloud cover due to a volcanic eruption. The brightness of the star (also closest known to transit and only known naked eye star to do so) makes it more easily studied than other hot super Earths. It was found to be dark and its sun-facing side hot enough to melt metal. It became the first super Earth to have its atmospheric composition measured (mostly hydrogen and helium with hints of hydrogen cyanide which would only dominate in a carbon-rich environment and no traces of water vapor) and temperature mapped, and the large hemispherical temperature differences suggest little atmosphere to transport heat. Planet b (one of the original 4 Hot Jupiters discovered) is the first "warm Jupiter" found to have a puffed up atmosphere and it probably at the outer limit from the star at which a planet can lose its atmosphere in this way. Its outer atmosphere skims the surface of the star, which was detected when attempting to detect an atmosphere around transiting Janssen. The strong interaction between planets Galileo and Brahe can be detected in measurements, and it took a while to find a fit that would allow them to survive over long periods of time. Harriot is a very eccentric Saturnian in the habitable zone. Planet d is a super jovian at Jupiter-like distances, which was the first found at true Jupiter distances and still the exoplanet discovered with dopplar spectrometry with the largest known semi-major axis. It was first thought to be circular, then eccentric, and then circular again. The distant outer star causes Lippershey's axis to flip on its axis every million years. Lippershey in turn causes the other planets to flip, including its star. The axis tilt of transiting planet e should be determined at some point. "Bode's law" predicts four undiscovered planets. One of the first 20 exoplanet systems allowed to be given common names by the IAU.



Note: Old Description for planet e: Planet e was the first Neptunian discovered. It was later found to be the shortest-period planet discovered (18 hours) and to transit. The planet has about half of Neptune's mass, but is Earth-like in size and density (2.17 Earth Radius). It is composed 70% of rock and the outer 30% is likely an ocean of super-critical water (between a gas and liquid state) that is 3000km thick. This is the hottest and densest super-Earth and the is the most watery planet found to date. It likely possesses a thick atmosphere of CO and CO2. The brightness of the star (also closest known to transit and only known naked eye star to do so) makes it more easily studied than other hot super Earths.

My Thoughts[]

Naming[]

This was discovered by Americans, among the first found. It's in the crab constellation. There's a nice crab themed naming set, but they never changed the star's name. That's no fun. Can I vote for it?? Well, you'd always see Cancri in the name, reminding you of crabs, so what the heck. There's some other neat names from other cultures, but there's no reason why to use this system. Scyllae, Tachypleus, Birgus, (Para)Lithodes, Uca.


55 Cancri System Web Pages[]

55 Cancri System In the News[]

Three New 51 Pegasi Type Planets Discovered (1996)[]

See also Tau Bootis System, Upsilon Andromedae System

Planet d First Planet in True Jupiter-Like Orbit Found (2002)[]

Neptunian Planet e Discovered (Aug 2004)[]

A fourth planet is discovered in the system, making 55 Cancri the first known 4-planet system. The new planet is the second/third Neptunian planet discovered along with Gliese 436 b after Mu Arae System.

Controversy Over First Neptunian Discovered (Sep 2004)[]

Models Predict Earthlike Planet Could Form Here (2006)[]

Planet e Orbit Unstable? (2006)[]

Saturnian f Discovered in HZ (2007)[]

Bode's Law Predicts One More Planet[]

http://arxiv.org/abs/0803.2240

Planet e's Year Shortened to the Smallest Known (2010)[]

Planet e Transit Detected (2011)[]

Bode's Law Predicts Four More Planets[]

Planet e Less Dense Than Thought (Sep 2011)[]

Planet e Covered in Super-Critical Water (Nov 2011)[]

Star Causes Outer Planet to Flip on Axis (2011)[]

Recap on Super Earths (2012)[]

E Could Have Super-Critical Fluids Seeping From Rocks (Jan 2012)[]

E First Super Earth Whose Light Is Detected (2012)[]

Planet e Likely Made of Diamond (2012)[]

Planet b First Puffed Up Warm Jupiter (2012)[]

Some Super Earths More Like Mini Neptunes[]

See Kepler-11 System, Gliese 1214 System, 55 Cancri System

Planet e Not Diamond After All (2013)[]

Interaction of Inner Jovians Stable (2014)[]

Planet e Volcanism Detected? (2015)[]

One of the Top 20 Exoplanetary Systems First Up For Naming (May 2015)[]

Janssen Atmospheric Measurements Taken (Feb 2016)[]

Also referenced Gliese 1214 System, HD 97658 System

Planet e Climate Mapped (2016)[]

55 Cancri System Fun Links[]

  • article - Is the planet Republican or Democrat?

See Also[]

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