Discovery | |
---|---|
Discovered by | Borucki et al. |
Discovery site | Kepler Space Observatory |
Discovery date | 18 April 2013 [1] |
Transit (Kepler Mission) [1] | |
Orbital characteristics | |
0.427 ± 0.004 [1] AU | |
Eccentricity | ~0 [1] |
122.3874 ± 0.0008 [1] d | |
Inclination | 89.98 ± 0.032 [1] |
Star | Kepler-62 (KOI-701) |
Physical characteristics | |
1.61 ± 0.05 [1] R🜨 | |
Mass | 4.5+14.2 −2.6 [2] ME |
Temperature | Teq: 270 K (−3 °C; 26 °F) |
Kepler-62e (also known by its Kepler Object of Interest designation KOI-701.03) is a super-Earth exoplanet (extrasolar planet) 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 (300 parsecs ) from Earth in the constellation of Lyra. [3] 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. [1] [4]
Kepler-62e orbits its host star every 122 days and is roughly 60 percent larger (in diameter) than Earth. [5]
Kepler-62e is a super-Earth with a radius 1.61 times that of Earth. [1] This is just above the 1.6 R🜨 limit above which planets may be more gaseous than they are rocky, so Kepler-62e may likely be a mini-Neptune. It has an equilibrium temperature of 270 K (−3 °C ; 26 °F ). It has an estimated mass of 4.5 ME, although the true value cannot be determined; upper limits place it at 18.7 ME, [2] which is highly unlikely to be true, as it would indicate a density of at least around 22.54 g/cm3.
The planet orbits a (K-type) star named Kepler-62, orbited by a total of five planets. [1] The star has a mass of 0.69 M☉ and a radius of 0.64 R☉. It has a temperature of 4,925 K (4,652 °C; 8,405 °F) and is 7 billion years old. [1] In comparison, the Sun is 4.6 billion years old [6] and has a temperature of 5,778 K (5,505 °C; 9,941 °F). [7] The star is somewhat metal-poor, with a metallicity ([Fe/H]) of −0.37, or 42% of the solar amount. [1] Its luminosity (L☉) is 21% that of the Sun. [1]
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 13.65 and therefore too dim to be seen with the naked eye.
Kepler-62e orbits its host star with an orbital period of 122.3 days at a distance of about 0.42 AU (compared to the distance of Mercury from the Sun, which is about 0.38 AU (57 million km ; 35 million mi )). A 2016 study came to a conclusion that the orbits of Kepler-62f and Kepler-62e are likely in a 2:1 orbital resonance. [8] This means that for every two orbits of planet "e", "f" completes one around its star. Kepler-62e might receives about 20% morelight from its star than Earth does from the Sun. [1]
Given the planet's age (7 ± 4 billion years), stellar flux (1.2 ± 0.2 times Earth's) and radius (1.61 ± 0.05 times Earth's), a rocky (silicate-iron) composition with the addition of a possibly substantial amount of water is considered plausible. [1] A modeling study suggests it is likely that a great majority of planets in Kepler-62e's size range are completely covered by ocean. [9] [10]
However, given that some studies show that super-Earths above 1.6 R🜨 may have a volatile-rich composition (similar to a mini-Neptune), and Kepler-62e's radius is estimated to be 1.61 R🜨, it may be a gaseous planet with no definite surface, and thus may not be habitable to known terrestrial life forms. [11]
Another factor that is critical is the stellar flux for Kepler-62e: at 20% more than that which Earth receives from the Sun, it is possible that the surface temperature of Kepler-62e may be over 350 K (77 °C; 170 °F), enough to trigger a runaway greenhouse effect. Such flux may reduce the habitability factors.
In 2009, NASA's Kepler spacecraft was completing observing stars on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In this last test, Kepler observed 50,000 stars in the Kepler Input Catalog, including Kepler-62; the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the group to examine further at observatories. Observations for the potential exoplanet candidates took place between 13 May 2009 and 17 March 2012. After observing the respective transits, which for Kepler-62e occurred roughly every 122 days (its orbital period), it was eventually concluded that a planetary body was responsible for the periodic dimming. This discovery and details about the planetary system of the star Kepler-69 were announced on April 18, 2013. [1]
On 9 May 2013, a congressional hearing Archived 2014-12-06 at the Wayback Machine by two U.S. House of Representatives subcommittees discussed "Exoplanet Discoveries: Have We Found Other Earths?," prompted by the discovery of exoplanet Kepler-62f, along with Kepler-62e and Kepler-69c. A related special issue of the journal Science, published earlier, described the discovery of the exoplanets. [13] Kepler-62f and the other Kepler-62 exoplanets are being specially targeted as part of the SETI search programs. [14]
At a distance of nearly 1,200 light-years (370 pc), Kepler-62e is too remote and its star too far away for current telescopes, or the next generation of planned telescopes, to determine its mass or whether it has an atmosphere. The Kepler spacecraft focused on a single small region of the sky, but next-generation planet-hunting space telescopes, such as TESS and CHEOPS, will examine nearby stars throughout the sky.
Nearby stars with planets can then be studied by the James Webb Space Telescope and future large ground-based telescopes to analyze atmospheres, determine masses and infer compositions. Additionally, the Square Kilometer Array should significantly improve radio observations over the Arecibo Observatory and Green Bank Telescope. [15]
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.
Kepler-16b is a Saturn-mass exoplanet consisting of half gas and half rock and ice. It orbits a binary star, Kepler-16, with a period of 229 days. "[It] is the first confirmed, unambiguous example of a circumbinary planet – a planet orbiting not one, but two stars," said Josh Carter of the Center for Astrophysics | Harvard & Smithsonian, one of the discovery team.
Kepler-22b is an exoplanet orbiting within the habitable zone of the Sun-like star Kepler-22. It is located about 640 light-years from Earth in the constellation of Cygnus. It was discovered by NASA's Kepler Space Telescope in December 2011 and was the first known transiting planet to orbit within the habitable zone of a Sun-like star, where liquid water could exist on the planet's surface. Kepler-22 is too dim to be seen with the naked eye.
Kepler-47c is an exoplanet orbiting the binary star system Kepler-47, the outermost of three such planets discovered by NASA's Kepler spacecraft. The system, also involving two other exoplanets, is located about 3,400 light-years away.
Kepler-69c is a confirmed super-Earth exoplanet, likely rocky, orbiting the Sun-like star Kepler-69, the outermore of two such planets discovered by NASA's Kepler spacecraft. It is located about 2,430 light-years from Earth.
Kepler-62 is a K-type main sequence star cooler and smaller than the Sun, located roughly 980 light-years from Earth in the constellation Lyra. It resides within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets that may be transiting their stars. On April 18, 2013, it was announced that the star has five planets, two of which, Kepler-62e and Kepler-62f are within the star's habitable zone. The outermost, Kepler-62f, is likely a rocky planet.
Kepler-62f is a super-Earth exoplanet orbiting within the habitable zone of the star Kepler-62, the outermost of five such planets discovered around the star by NASA's Kepler space telescope. It is located about 982 light-years from Earth in the constellation of Lyra.
Kepler-62c is an approximately Mars-sized exoplanet discovered in orbit around the star Kepler-62, the second innermost of five discovered by NASA's Kepler spacecraft around Kepler-62. At the time of discovery it was the second-smallest exoplanet discovered and confirmed by the Kepler spacecraft, after Kepler-37b. It was found using the transit method, in which the dimming that a planet causes as it crosses in front of its star is measured. Its stellar flux is 25 ± 3 times Earth's. It is similar to Mercury.
Kepler-62d is the third innermost and the largest exoplanet discovered orbiting the star Kepler-62, with a size roughly twice the diameter of Earth. It was found using the transit method, in which the dimming that a planet causes as it crosses in front of its star is measured. Its stellar flux is 15 ± 2 times Earth's. Due to its closer orbit to its star, it is a super-Venus or, if it has a volatile composition, a hot Neptune, with an estimated equilibrium temperature of 510 K, too hot to sustain life on its surface.
Kepler-62b is the innermost and the second smallest discovered exoplanet orbiting the star Kepler-62, with a diameter roughly 30% larger than Earth. It 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. It is likely to have an equilibrium temperature slightly higher than the surface temperature of Venus, high enough to melt some types of metal. Its stellar flux is 70 ± 9 times Earth's.
Kepler-61b is a super-Earth exoplanet orbiting within parts of the habitable zone of the K-type main-sequence star Kepler-61. It is located about 1,100 light-years from Earth in the constellation of Cygnus. It was discovered in 2013 using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured, by NASA's Kepler spacecraft.
Kepler-186f is an Earth-sized exoplanet orbiting within the habitable zone of the red dwarf star Kepler-186, the outermost of five such planets discovered around the star by NASA's Kepler space telescope. It is located about 580 light-years from Earth in the constellation of Cygnus.
Kepler-438b is a confirmed near-Earth-sized exoplanet. It is likely rocky. It orbits on the inner edge of the habitable zone of a red dwarf, Kepler-438, about 460.2 light-years from Earth in the constellation Lyra. It receives 1.4 times our solar flux. The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the confirmation of the exoplanet on 6 January 2015.
Kepler-442b is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star Kepler-442, about 1,196 light-years (367 pc) from Earth in the constellation of Lyra.
Kepler-452b is a super-Earth exoplanet orbiting within the inner edge of the habitable zone of the sun-like star Kepler-452 and is the only planet in the system discovered by the Kepler space telescope. It is located about 1,400 light-years (430 pc) from Earth in the constellation of Cygnus.
Kepler-419c is a super-Jupiter exoplanet orbiting within the habitable zone of the star Kepler-419, the outermost of two such planets discovered by NASA's Kepler spacecraft. It is located about 3,400 light-years from Earth in the constellation Cygnus. The exoplanet was found by using the transit timing variation method, in which the variations of transit data from an exoplanet are studied to reveal a more distant companion.
Kepler-1229b is a confirmed super-Earth exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf Kepler-1229, located about 870 light years from Earth in the constellation of Cygnus. It was discovered in 2016 by the Kepler space telescope. 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-1229 is a red dwarf star located about 875 light-years (268 pc) away from the Earth in the constellation of Cygnus. It is known to host a super-Earth exoplanet within its habitable zone, Kepler-1229b, which was discovered in 2016.
K2-72e (also known by its EPIC designation EPIC 206209135.04), is a confirmed exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf star K2-72, the outermost of four such planets discovered in the system by NASA's Kepler spacecraft on its "Second Light" mission. It is located about 217.1 light-years (66.56 parsecs, or nearly 2.0538×1015 km) away from Earth in the constellation of Aquarius. 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-1649c is an Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf star Kepler-1649, the outermost planet of the planetary system discovered by Kepler’s space telescope. It is located about 301 light-years (92 pc) away from Earth, in the constellation of Cygnus.