Famous Exoplanets, Introduction to Exoplanets

Pi Mensae c

Oct 2, 2018 by exoplanetkyo

Pi Mensae c orbits around a somewhat large and bright G-type star Pi Mensae, and is categorized as a Super Earth, with a radius of about two times that of Earth. This planet was first reported in arXiv in September 2018, the first exoplanet discovered by TESS, the Transiting Exoplanet Survey Satellite. Furthermore, another orbiting planet, Pi Mensae b was discovered in 2001 and was found to have a mass 10 times that of Jupiter.

Pi Mensae c is thought to have a small mass relative to its size and be less dense than the Earth. Therefore, it is presumed to be a planet with a lot of water, or have a thick atmosphere. Also, since the distance from the host star is only about 1/50 of the distance from the sun to Mercury, water is thought to evaporate at very high temperatures on its surface.

Pi Mensae c is about 60 light-years away from the earth and the apparent magnitude is 5.67, so if you are in a very dark environment you can see it with the naked eye. If you are ever traveling in the southern hemisphere and see this star, you can tell everyone that “a Super Earth revolves around that star!”

For more information on Pi Mensae c, please see the ExoKyoto database:

http://www.exoplanetkyoto.org/exohtml/pi_Men_cJP.html

<Pi Mensae b> Super Jupiter with an eliptical orbit.

Two exoplanets have been discovered orbiting the main sequence star Pi Mensae (HD 39091), which is said to have a radius of 2.1 times the sun. The first, Pi Mensae b (HD39091b) was discovered in 2001. This planet is thought to have a mass of 10.02 times that of Jupiter, and it has an elliptical orbit of around 1-5 astronomical units from its host star. This orbit goes from just inside the Venus-equivalent orbit, to the outside of the habitable zone and takes about 2093 days. The radius of Pi Mensa b has yet to be accurately observed.

For more information on Pi Mensae b, please see the ExoKyoto database:

http://www.exoplanetkyoto.org/exohtml/pi_Men_bJP.html

Mensa comes from the Latin meaning “table.” In Japanese, the Mensa constellation is “table-san” which translates to “table mountain.” Table Mountain (Mons Mensae in Latin), al plateau-like mountain overlooking the city in Cape Town, South Africa, which is a characteristic topography around the Cape of Good Hope. It is one of the 14 (12) constellations in the southern sky discovered by the French astronomer Abbé Nicolas-Louis de Lacaille.

A photo of Table Mountain for reference.

Famous Exoplanets, Introduction to Exoplanets

Kepler-283 c

Aug 7, 2018 by exoplanetkyo

Kepler-283 c is located 1741.0 light-years (534 parsecs) from our solar system and was discovered in 2014 orbiting it’s host star Kepler-283. The apparent magnitude of the host star is 13.9 and the absolute magnitude is 5.3. Kepler-283 is about 0.8 the mass of our sun and has about 0.6 the radius. Its surface temperature is 4351 K and is a spectral K5 type star. The planet Kepler-283 c orbits the star every 92.7days, it’s orbital radius is 0.34 SEAU.

According to an announcement from NASA, this planet is located in the habitable zone. ExoKyoto has come up with the same conclusion. Kepler-283 c is the only habitable planet in which superflares from the host star (Kepler-283) were observed during observation with the Kepler Space Telescope. Based on this, the estimated radiation exposure dose was calculated for various cases, taking into account the frequency of flares, but the doses were level and none caused problems (Yamashiki et al. 2019 ApJ).

A second planet, Kepler-283 b, has also been found in the Kepler-283 solar system, which is a Hot Jupiter located inside the habitable zone.

For more information on Kepler-283 c, please visit the ExoKyoto database page below. http://www.exoplanetkyoto.org/exohtml/Kepler-283_cJP.html

Famous Exoplanets, Introduction to Exoplanets

CoRoT-14 b

Jul 6, 2018 by exoplanetkyo

CoRoT-14b is a Super Earth exoplanet orbiting an F-type star. The mass is 7.6 that of Jupiter, and it takes 1.5 days to orbit its host star at 0.027 AU. It was discovered in 2010.

Journal Articles

1.) Transiting exoplanets from the CoRoT space mission XVI. CoRoT-14b: an unusually dense very hot Jupiter

WEB Articles

1.) CoRoT-14 b

Introduction to Exoplanets

CoRoT-20 b

Jul 6, 2018 by exoplanetkyo

CoRoT-20b is a new planet that baffles astronomers by defying current theories for how planets form. It orbits close to a sunlike star, according to National Geographic.

The planet, which is four-fifths the size of Jupiter, was discovered 4,000 light-years away, and reported by a French site MaxiSciences. CoRoT-20b is thought to be a gas giant and, despite its relatively small size, it has four times Jupiter’s mass, making it one of the densest known planets.

If the new dense planet has the same structure as a traditional gas giant — a solid core surrounded by a gassy atmosphere — the planet’s core would make up 50% to 77% of its total mass. Jupiter’s core, on the other hand, represents only 15% of its own mass.

The host star CoRoT 20 has an apparent magnitude of 14.7, with an absolute magnitude of 4.21. It is 1.14 times more massive and 0.92 times bigger than our sun. The surface temperature is 5880 K which means its spectral type is G2V. In this planetary system, the extrasolar planet CoRoT 20 b orbits around the host star at an orbital distance of 0.0902.

Journal Articles

1.) Transiting exoplanets from the CoRoT space mission XX. CoRoT-20b: A very high density, high eccentricity transiting giant planet

https://www.aanda.org/articles/aa/full_html/2012/02/aa17681-11/aa17681-11.html

WEB Articles

1.) CoRoT-20b: new planet found

https://www.pri.org/stories/2012-02-24/corot-20b-new-planet-found

Introduction to Exoplanets

CoRoT-27 b

Jul 6, 2018 by exoplanetkyo

Parviainen H. et al. (2014) reported the discovery of a massive high-density planet on a close-in 3.58 day orbit around a 4.2 billion-year-old Sun-like star. The planet has been identified as CoRoT-27b. Like Jupiter, CoRoT-27b is a gas-giant. It was detected by the CoRoT space telescope using the transit method, in which a planet periodically transits its host star and blocks a small fraction of the star’s light. CoRoT-27b weighs in at 10.39 ± 0.55 Jupiter-mass and has 1.01 ± 0.04 times the radius of Jupiter. This gives CoRoT-27b a mean density of 12.6 times the density of water, which is more than twice the mean density of Earth and almost 10 times the mean density of Jupiter.

Like Jupiter, CoRoT-27b is a gaseous planet comprised primarily of hydrogen and helium. The structure and composition of CoRoT-27b can be inferred from two models. For the first model, the planet is assumed to be made of a central rocky core surrounded by an extensive hydrogen-helium envelope. The first model is consistent with a heavy element mass fraction of 0.11, representing a core mass of 366 Earth-masses. For the second model, a central rocky core is absent and the heavy elements are present throughout the hydrogen-helium envelope. The second model is consistent with a heavy element mass fraction of 0.07, representing a heavy element mass of 219 Earth-masses.

Given its high mass, gravity on the surface of CoRoT-27b is 27 times the surface gravity on Earth. Technically, CoRoT-27b does not have a surface since it is gaseous throughout, right down to a central rocky core, if one is present. Being so near its host star, the equilibrium temperature on CoRoT-27b is estimated to be 1500 ± 130 K. The discovery of CoRoT-27b is an important addition to a scarcely populated class of massive close-in planets.

The host star CoRoT 27 has an apparent magnitude of 15.5, with an absolute magnitude of 25.00. It is 1.05 times more massive and 1.08 times larger compared to our sun. The surface temperature is 5900 K and it has a spectral type of G2. In this planetary system, the extrasolar planet CoRoT 27 b orbits around the star CoRoT 27 at an orbital distance of 0.0476.

Journal Articles

1.) Transiting exoplanets from the CoRoT space mission XXV. CoRoT-27b: a massive and dense planet on a short-period orbit?

WEB Articles

1.) CoRoT-27b: A Massive and Dense Planet

2.) CoRoT-27b, a massive, dense planet on a short-period orbit about a G-type star.

Introduction to Exoplanets

EPIC 220674823

Jul 6, 2018 by exoplanetkyo

Two transiting planets have been identified orbiting K2 target EPIC 220674823, or an alternative name, K2-106. One object is an ultra-short-period planet (USP) with an orbital period of just 0.57 days (13.7 hours), while the other has a period of 13.3 days. Both planets are small, with the former having a radius of Rp1 = 1.5 R⊕ and the latter Rp2 = 2.5 R⊕. Follow-up observations, including radial velocity (with uncertainties of 110 ms −1 ) and high-resolution adaptive optics imagery, show no signs of stellar companions. EPIC 220674823 is the 12th confirmed or validated planetary system in which an ultra-short-period planet (i.e., having an orbital period less than 1 day) is accompanied by at least one additional planet, suggesting that such systems may be common and must be accounted for in models for the formation and evolution of such extreme systems.

For more information about EPIC 220674823, please visit the ExoKyoto database:

http://www.exoplanetkyoto.org/exohtml/EPIC_220674823.html

For more information about the exoplanets orbiting EPIC 220674823, please visit the following pages:

http://www.exoplanetkyoto.org/exohtml/K2-106_b.html

http://www.exoplanetkyoto.org/exohtml/K2-106_c.html

Journal Articles

1.) ULTRA SHORT PERIOD PLANETS IN K2 WITH COMPANIONS: A DOUBLE TRANSITING SYSTEM FOR EPIC 220674823

2.) The high-resolution cross-dispersed echelle white-pupil spectrometer of the McDonald Observatory 2.7-m telescope

WEB Articles

1.) EPIC 220674823

http://www.openexoplanetcatalogue.com/planet/EPIC%20220674823%20b/