Kepler-11e

Last updated

Kepler-11e
Exoplanet Comparison Kepler-11 e.png
Size comparison of Kepler-11e (gray) with Neptune.
Discovery
Discovery date2 February 2011 [1]
Transit (Kepler Mission) [1]
Orbital characteristics
0.194 AU (29,000,000 km)
31.99590 [2] d
Inclination 88.8 [2]
Star Kepler-11 (KOI-157)
Physical characteristics
4.52 (± 0.43) [3] R🜨
Mass 8.4 +2.5
1.9
[3] ME
Mean density
0.5 (± 0.2) [3] g cm−3
Temperature 617 K (344 °C; 651 °F) [4]

    Kepler-11e is an exoplanet (extrasolar planet) discovered in the orbit of the sunlike star Kepler-11. It is the fourth of six planets around Kepler-11 discovered by NASA's Kepler space telescope. Kepler-11e was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. Kepler-11e is most likely a gas giant like Neptune, having a density that is less than that of Saturn, the least dense planet in the Solar System. [5] Its low density can probably be attributed to a large hydrogen and helium atmosphere. [1] Kepler-11e has a mass eight times of Earth's mass and a radius 4.5 times that of Earth. The planet orbits its star every 31 days in an ellipse that would fit within the orbit of Mercury. Kepler-11e was announced on February 2, 2011 with its five sister planets after it was confirmed by several observatories.

    Contents

    Name and discovery

    At the time when Kepler-11 was first noted as a host to a potential transit event, the star was given the designation KOI-157. [2] It was later assigned the name "Kepler-11" after the Kepler spacecraft, a NASA satellite tasked with discovering planets in transit of, or crossing in front of, their stars. This transit causes a slight and regular change in the host star's brightness, which can then tested to prove the planet's existence and, later, to extrapolate the orbital parameters of the planet. [6] Kepler-11e is first given the designation by its host star, Kepler-11. Since Kepler-11e was announced with five other planets, the letters added to the star are sorted by the planet's distance from its star. Kepler-11e is the fourth planet from Kepler-11, it is given the designation "e".

    Follow-up confirmation observations were made by the Keck 1 telescope at the W. M. Keck Observatory in Hawaii, the Hale and Shane telescopes in California, the Harlan J. Smith and Hobby–Eberly telescopes in west Texas, the Nordic Optical Telescope in the Canary Islands, and by telescopes at the WIYN (including MMT) and Whipple observatories in Arizona. The Spitzer Space Telescope was also used. Kepler-11's planetary system became the first discovered extrasolar system with more than three transiting planets, as well as the most compact and flattest system yet discovered, according to NASA. [6] The planets of Kepler-11, including Kepler-11e, were announced jointly at a press conference on February 2, 2011. The findings were published in the journal Nature on February 3. [1]

    Host star

    Kepler-11 is a G-type star [4] located in the constellation of Cygnus. It has a mass of 0.95 Msun and a radius of 1.1 Rsun, and is thus almost the same mass and radius as the Sun. With an effective temperature of 5680 K, it is also almost as hot as the Sun, and with a metallicity of 0, Kepler-11 is almost as metal-rich as the Sun is. Metal-rich stars tend to have easily detectable planets [7] because higher metallicities tend to either facilitate the creation of gas giants or to promote planetary migration, in which the planet orbits more closely to its star. [8] However, Kepler-11 is almost 1.73 times older than the Sun, as it has an estimated age of eight billion years. [2] Kepler-11 is 613 parsecs away from the Earth; its distance contributes to its apparent magnitude of 14.2 (V). It, thus, cannot be seen with the naked eye. [2] Other than Kepler-11e, Kepler-11 is the host star of the planets Kepler-11b, Kepler-11c, Kepler-11d, Kepler-11f, and Kepler-11g. The inner five planets in the system orbit in a tightly knit configuration that would fit within the orbit of planet Mercury, while Kepler-11g, compared to its inner sister planets, orbits at a much further distance. [1]

    Characteristics

    A comparison of the Kepler planets as compared to Earth, Jupiter, and previous Kepler finds. Kepler-11e is in purple at the bottom. Kepler-11 planets comparison.jpg
    A comparison of the Kepler planets as compared to Earth, Jupiter, and previous Kepler finds. Kepler-11e is in purple at the bottom.

    Kepler-11e, which formed within the first few million years of the star system's formation, [9] has a mass 8.4 times that of Earth's, and radius 4.52 times that of Earth's. With a density of 0.5 grams/cm3, Kepler-11e has a density that is half of that of pure water at standard temperature and pressure and slightly less than the density of Saturn. [5] Kepler-11e has a surface equilibrium temperature of 617 K, and is thus has an equilibrium temperature approximately 2.4 times hotter than Earth's. Kepler-11e orbits its star at a mean distance of .194 AU, making it the fourth planet from its star. It completes an orbit every 31.995990 days. In comparison, Mercury orbits the Sun every 87.97 days at a distance of 0.387 AU. [10] Kepler-11e's orbital inclination is 88.8°, making it almost entirely edge-on to its star as seen from Earth. [2]

    Because it isn't as close to its star as its sister planets Kepler-11b and Kepler-11c, the Kepler team suggests that its light density may come from a large hydrogen and helium atmosphere that has not been blown away by the stellar wind. [1] In fact, formation models indicate that the planet has a gaseous envelope, somewhat less massive than 20% of it total mass, which account for ≈60% of its radius (or ≈90% of its volume). [11]

    Related Research Articles

    <span class="mw-page-title-main">Super-Earth</span> Type of exoplanet

    A Super-Earth is a type of exoplanet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term.

    <span class="mw-page-title-main">Kepler-7b</span> Hot Jupiter orbiting Kepler-7

    Kepler-7b is one of the first five exoplanets to be confirmed by NASA's Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It orbits a star slightly hotter and significantly larger than the Sun that is expected to soon reach the end of the main sequence. Kepler-7b is a hot Jupiter that is about half the mass of Jupiter, but is nearly 1.5 times its size; at the time of its discovery, Kepler-7b was the second most diffuse planet known, surpassed only by WASP-17b. It orbits its host star every five days at a distance of approximately 0,06 AU. Kepler-7b was announced at a meeting of the American Astronomical Society on January 4, 2010. It is the first extrasolar planet to have a crude map of cloud coverage.

    <span class="mw-page-title-main">Kepler-5b</span> Extrasolar planet

    Kepler-5b is one of the first five planets discovered by NASA's Kepler spacecraft. It is a hot Jupiter that orbits a subgiant star that is more massive, larger, and more diffuse than the Sun is. Kepler-5 was first flagged as the location of a possibly transiting planet, and was reclassified as a Kepler Object of Interest until follow-up observations confirmed the planet's existence and many of its characteristics. The planet's discovery was announced at a meeting of the American Astronomical Society on January 4, 2010. The planet has approximately twice the mass of Jupiter, and is about 1.5 times larger. It is also fifteen times hotter than Jupiter. Kepler-5b orbits Kepler-5 every 3.5 days at a distance of approximately 0.051 AU.

    Kepler-8 is a star located in the constellation Lyra in the field of view of the Kepler Mission, a NASA-led operation tasked with discovering terrestrial planets. The star, which is slightly hotter, larger, and more massive than the Sun, has one gas giant in its orbit, Kepler-8b. This gas giant is larger than Jupiter, but is less massive, and thus more diffuse. The planet's discovery was announced to the public on January 4, 2010 along with four other planets. As the fifth confirmed planetary system verified by Kepler, it helped demonstrate the capabilities of the Kepler spacecraft.

    <span class="mw-page-title-main">Kepler-9b</span> Extrasolar planet

    Kepler-9b is one of the first planets discovered outside the solar system (exoplanets) by NASA's Kepler Mission. It revolves around the star Kepler-9 within the constellation Lyra. Kepler-9b is the largest of three planets detected in the Kepler system by transit method; its mass is roughly half that of the planet Saturn, and it is the largest planet in its system. Kepler-9b and Kepler-9c display a phenomenon called orbital resonance, in which gravitational pull from each planet alters and stabilizes the orbit of the other. The planet's discovery was announced on August 26, 2010.

    <span class="mw-page-title-main">Discoveries of exoplanets</span> Detecting planets located outside the Solar System

    An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 24 July 2024, there are 7,026 confirmed exoplanets in 4,949 planetary systems, with 1007 systems having more than one planet. This is a list of the most notable discoveries.

    <span class="mw-page-title-main">Kepler-10b</span> Terrestrial exoplanet orbiting Kepler-10

    Kepler-10b is the first confirmed terrestrial planet to have been discovered outside the Solar System by the Kepler Space Telescope. Discovered after several months of data collection during the course of the NASA-directed Kepler Mission, which aims to discover Earth-like planets crossing in front of their host stars, the planet's discovery was announced on January 10, 2011. Kepler-10b has a mass of 3.72±0.42 Earth masses and a radius of 1.47 Earth radii. However, it lies extremely close to its star, Kepler-10, and as a result is too hot to support life as we know it. Its existence was confirmed using measurements from the W.M. Keck Observatory in Hawaii.

    <span class="mw-page-title-main">Kepler-10</span> Sunlike star in the constellation Draco

    Kepler-10, formerly known as KOI-72, is a Sun-like star in the constellation of Draco that lies 607 light-years from Earth. Kepler-10 was targeted by NASA's Kepler space telescope, as it was seen as the first star identified by the Kepler mission that could be a possible host to a small, transiting exoplanet. The star is slightly less massive, slightly larger, and slightly cooler than the Sun; at an estimated 11.9 billion years in age, Kepler-10 is 2.3 times the age of the Sun.

    <span class="mw-page-title-main">Kepler-11</span> Sun-like star in the constellation Cygnus

    Kepler-11, also designated as 2MASS J19482762+4154328, is a Sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,110 light years from Earth. It is located within the field of vision of the Kepler space telescope, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars. Announced on February 2, 2011, the star system is among the most compact and flattest systems yet discovered. It is the first discovered case of a star system with six transiting planets. All discovered planets are larger than Earth, with the larger ones being about Neptune's size.

    <span class="mw-page-title-main">Kepler-11b</span> Exoplanet orbiting Kepler-11

    Kepler-11b is an exoplanet discovered around the star Kepler-11 by the Kepler space telescope, a NASA-led mission to discover Earth-like planets. Kepler-11b is less than about three times as massive and twice as large as Earth, but it has a lower density, and is thus most likely not of Earth-like composition. Kepler-11b is the hottest of the six planets in the Kepler-11 system, and orbits more closely to Kepler-11 than the other planets in the system. Kepler-11b, along with its five counterparts, form the first discovered planetary system with more than three transiting planets—the most densely packed known planetary system. The system is also the flattest known planetary system. The discovery of this planet and its five sister planets was announced on February 2, 2011, after follow-up investigations.

    <span class="mw-page-title-main">Kepler-11c</span> Extrasolar planet orbiting Kepler-11

    Kepler-11c is an exoplanet discovered in the orbit of the Sun-like star Kepler-11 by the Kepler space telescope, a NASA telescope aiming to discover Earth-like planets. It is the second planet from its star, and is most likely a water planet with a thin hydrogen–helium atmosphere. Kepler-11c orbits Kepler-11 every 10 days, and has an estimated density twice that of pure water. It is estimated to have a mass thirteen times that of Earth and a radius three times that of Earth. Kepler-11c and its five sister planets form the first discovered system with more than three transiting planets. The Kepler-11 system also holds the record of being the most compact and the flattest system discovered. Kepler-11c and the other Kepler-11 planets were announced to the public on February 2, 2011, and was published in Nature a day later.

    <span class="mw-page-title-main">Kepler-11d</span> Extrasolar planet

    Kepler-11d is an exoplanet discovered in the orbit of the sun-like star Kepler-11. It is named for the telescope that discovered it, a NASA spacecraft named Kepler that is designed to detect Earth-like planets by measuring small dips in the brightness of their host stars as the planets cross in front. This process, known as the transit method, was used to note the presence of six planets in orbit around Kepler-11, of which Kepler-11d is the third from its star. Kepler-11d orbits Kepler-11 well within the orbit of Mercury approximately every 23 days. The planet is approximately six times more massive than the Earth, and has a radius that is three and a half times larger than that of Earth's. It is, however, far hotter than Earth is. Its low density, comparable to that of Saturn, suggests that Kepler-11d has a large hydrogen–helium atmosphere. Kepler-11d was announced with its five sister planets on February 2, 2011 after extensive follow-up studies.

    <span class="mw-page-title-main">Kepler-11f</span> Extrasolar planet

    Kepler-11f is an exoplanet discovered in the orbit of the Sun-like star Kepler-11 by NASA's Kepler space telescope, which searches for planets that transit their host stars. Kepler-11f is the fifth planet from its star, orbiting one quarter of the distance of the Earth from the Sun every 47 days. It is the furthest of the first five planets in the system. Kepler-11f is the least massive of Kepler-11's six planets, at nearly twice the mass of Earth; it is about 2.6 times the radius of Earth. Along with planets d and e and unlike the two inner planets in the system, Kepler-11f has a density lower than that of water and comparable to that of Saturn. This suggests that Kepler-11f has a significant hydrogen–helium atmosphere. The Kepler-11 planets constitute the first system discovered with more than three transiting planets. Kepler-11f was announced to the public on February 2, 2011, after follow-up investigations at several observatories. Analysis of the planets and study results were published the next day in the journal Nature.

    <span class="mw-page-title-main">Kepler-11g</span> Extrasolar planet

    Kepler-11g is an exoplanet discovered in the orbit of the sunlike star Kepler-11 by the Kepler space telescope, a NASA satellite tasked with searching for terrestrial planets. Kepler-11g is the outermost of the star's six planets. The planet orbits at a distance of nearly half the mean distance between Earth and the Sun. It completes an orbit every 118 days, placing it much further from its star than the system's inner five planets. Its estimated radius is a little over three times that of Earth, i.e. comparable to Neptune's size. Kepler-11g's distance from the inner planets made its confirmation more difficult than that of the inner planets, as scientists had to work to exhaustively disprove all reasonable alternatives before Kepler-11g could be confirmed. The planet's discovery, along with that of the other Kepler-11 planets, was announced on February 2, 2011. According to NASA, the Kepler-11 planets form the flattest and most compact system yet discovered.

    <span class="mw-page-title-main">Kepler-9d</span> Super-Earth orbiting Kepler-9

    Kepler-9d is a planet in orbit around the Sun-like star Kepler-9. Initially discovered by Kepler space telescope, a terrestrial planet-searching satellite built and operated by NASA, Kepler-9d is most likely a Super-Earth, with an estimated radius approximately 60% larger than that of Earth's, although its exact mass cannot be determined. Kepler-9d orbits Kepler-9 every 1.56 days at a distance of .0273 AU from its star, an extremely close distance. Although Kepler-9d is the closest planet to its star in its system, it is named Kepler-9d instead of Kepler-9b because two gas giants, Kepler-9b and Kepler-9c, were confirmed first. The original studies into the system first suggested that Kepler-9d might be a planet, but a follow-up investigation made by the Kepler team later confirmed that it was; the confirmation of Kepler-9d as a planet was made public with the team's paper, which was published in the Astrophysical Journal on January 1, 2011. The team used telescopes at the W.M. Keck Observatory in Hawaii to follow up on the Kepler space telescope's initial discovery.

    <span class="mw-page-title-main">Kepler-20f</span> Terrestrial planet orbiting Kepler-20

    Kepler-20f (also known by its Kepler Object of Interest designation KOI-070.05) is an exoplanet orbiting the Sun-like star Kepler-20, the second outermost of five such planets discovered by NASA's Kepler spacecraft. It is located approximately 929 light-years (285 parsecs, or about 8.988×1015 km) from Earth in the constellation Lyra. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. The planet is notable as it has the closest radius to Earth known so far.

    Kepler-47 is a binary star system in the constellation Cygnus located about 3,420 light-years away from Earth. The stars have three exoplanets, all of which orbit both stars at the same time, making this a circumbinary system. The first two planets announced are designated Kepler-47b, and Kepler-47c, and the third, later discovery is Kepler-47d. Kepler-47 is the first circumbinary multi-planet system discovered by the Kepler mission. The outermost of the planets is a gas giant orbiting within the habitable zone of the stars. Because most stars are binary, the discovery that multi-planet systems can form in such a system has impacted previous theories of planetary formation.

    <span class="mw-page-title-main">Kepler-62e</span> Habitable-zone super-Earth planet orbiting Kepler-62

    Kepler-62e is a super-Earth exoplanet discovered orbiting within the habitable zone of Kepler-62, the second outermost of five such planets discovered by NASA's Kepler spacecraft. Kepler-62e is located about 990 light-years from Earth in the constellation of Lyra. The exoplanet was found using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. Kepler-62e may be a terrestrial or ocean-covered planet; it lies in the inner part of its host star's habitable zone.

    <span class="mw-page-title-main">Kepler-90h</span> Exoplanet in the constellation Draco

    Kepler-90h is an exoplanet orbiting within the habitable zone of the early G-type main sequence star Kepler-90, the outermost of eight such planets discovered by NASA's Kepler spacecraft. It is located about 2,840 light-years, from Earth in the constellation Draco. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.

    Kepler-277c is the third most massive and second-largest rocky planet ever discovered, with a mass about 64 times that of Earth. Discovered in 2014 by the Kepler Space Telescope, Kepler-277c is a Neptune-sized exoplanet with a very high mass and density for an object of its radius, suggesting a composition made mainly of rock with some amounts of water. Along with its sister planet, Kepler-277b, the planet's mass was determined using transit-timing variations (TTVs).

    References

    1. 1 2 3 4 5 6 Denise Chow (2 February 2011). "Astronomers Find 6-Pack of Planets in Alien Solar System". Space.com. Retrieved 22 March 2011.
    2. 1 2 3 4 5 6 "Kepler Discoveries". Ames Research Center . NASA. 2011. Archived from the original on 2010-05-27. Retrieved 23 March 2011.
    3. 1 2 3 Lissauer, Jack L.; et al. (2011-02-02). "A closely packed system of low-mass, low-density planets transiting Kepler-11". Nature. 470 (7332): 53–8. arXiv: 1102.0291 . Bibcode:2011Natur.470...53L. doi:10.1038/nature09760. PMID   21293371. S2CID   4388001.
    4. 1 2 Jean Schneider (2011). "Notes for star Kepler-11". Extrasolar Planets Encyclopaedia . Archived from the original on 7 February 2011. Retrieved 23 March 2011.
    5. 1 2 Fraser Cain (June 30, 2008). "Density of Saturn". Universe Today. Retrieved 2 April 2011.
    6. 1 2 Michael Mewinney and Rachel Hoover (2 February 2011). "NASA's Kepler Spacecraft Discovers Extraordinary New Planetary System". Ames Research Center . NASA . Retrieved 21 March 2011.
    7. Fischer, Debra A.; Valenti, Jeff (2005-04-01). "The planet-metallicity correlation". The Astrophysical Journal. 622 (2): 1102–1117. Bibcode:2005ApJ...622.1102F. doi: 10.1086/428383 .
    8. Seager, Sara (2010). "Statistical Distribution of Exoplanets by Andrew Cumming". Exoplanets. University of Arizona Press. pp. 191–214. ISBN   978-0-8165-2945-2.
    9. Denise Chow (4 February 2011). "A tourist's guide to the new Kepler-11 planet system". Space section. NBC News . Retrieved 13 March 2011.
    10. David Williams (2001). "Mercury Fact Sheet". Goddard Space Flight Center . NASA . Retrieved 23 March 2011.
    11. D'Angelo, G.; Bodenheimer, P. (2016). "In Situ and Ex Situ Formation Models of Kepler 11 Planets". The Astrophysical Journal. 828 (1): id. 33 (32 pp.). arXiv: 1606.08088 . Bibcode:2016ApJ...828...33D. doi: 10.3847/0004-637X/828/1/33 . S2CID   119203398.