Kepler-47

Last updated

Kepler-47
Observation data
Epoch J2000       Equinox J2000
Constellation Cygnus
Right ascension 19h 41m 11.49832s [1]
Declination +46° 55′ 13.7073″ [1]
Apparent magnitude  (V)15.4 [2]
Characteristics
Evolutionary stage Main sequence
Spectral type G6V / M4V
Astrometry
Proper motion (μ)RA: −3.383  mas/yr [1]
Dec.: −10.212  mas/yr [1]
Parallax (π)0.9540 ± 0.0208  mas [1]
Distance 3,420 ± 70  ly
(1,050 ± 20  pc)
Orbit [3]
PrimaryKepler-47A
CompanionKepler-47B
Period (P)7.4483648+0.0000038
−0.0000270  d
Semi-major axis (a)0.08145+0.00036
−0.00037  AU
Eccentricity (e)0.0288+0.0015
−0.0013
Inclination (i)89.613+0.045
−0.040°
Argument of periastron (ω)
(secondary)		226.3+2.8
−2.6°
Details [4] [3]
Kepler-47A
Mass 0.957+0.013
−0.015  M☉
Radius 0.936±0.005  R☉
Luminosity 0.840 ± 0.067  L☉
Surface gravity (log g)4.488 ± 0.01  cgs
Temperature 5636 ± 100  K
Metallicity [Fe/H]−0.25 ± 0.08  dex
Rotational velocity (v sin i)4.1+0.5
−0.35 km/s
Age 4–5  Gyr
Kepler-47B
Mass 0.342±0.003  M☉
Radius 0.338±0.002  R☉
Luminosity0.014 ± 0.002  L☉
Surface gravity (log g)4.9073 ± 0.0067  cgs
Temperature 3357 ± 100  K
Age 4–5  Gyr
Other designations
2MASS  J19411149+4655136, KOI-3154, KIC  10020423
Database references
SIMBAD data
KIC data

Kepler-47 is a binary star system in the constellation Cygnus located about 3,420 light-years (1,050 parsecs ) 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. [5] The outermost of the planets is a gas giant orbiting within the habitable zone of the stars. [6] Because most stars are binary, the discovery that multi-planet systems can form in such a system has impacted previous theories of planetary formation. [7] [5]

Contents

A group of astronomers led by Jerome Orosz at San Diego State University, including astronomers from Tel-Aviv University in Israel, discovered the planetary system via NASA's Kepler space telescope in 2012. [8] In November 2013, evidence of a third planet orbiting between the planets b and c, Kepler-47d, was announced. [9] Later analyses of transit data from the Kepler space telescope confirmed the existence of Kepler-47d. [10]

Nomenclature and history

The Kepler Space Telescope search volume, in the context of the Milky Way Galaxy. LombergA1024.jpg
The Kepler Space Telescope search volume, in the context of the Milky Way Galaxy.

Prior to Kepler observation, Kepler-47 had the 2MASS catalogue number 2MASS J19411149+4655136. In the Kepler Input Catalog it has the designation of KIC 10020423, and when it was found to have transiting planet candidates it was given the Kepler object of interest number of KOI-3154. [4]

Planetary candidates were detected around the pair of stars by NASA's Kepler Mission, a mission tasked with discovering planets in transit around their stars. [11] The discoverers referred the pair of stars as Kepler-47, which is the normal procedure for naming stars with exoplanets discovered by the spacecraft. [4] Hence, this is the name used by the public to refer to the pair of stars and its planets. Candidate planets that are associated with stars studied by the Kepler Mission are known as Kepler objects of interest (KOI) and are assigned the designations ".01", ".02", ".03" etc. after the star's name, in the order of discovery. [12] If planet candidates are detected simultaneously, then the ordering follows the order of orbital periods from shortest to longest. [12] Following these rules, two candidate planets were detected, with orbital periods of 49.51 and 303.158 days. [4] Upon confirmation, the planets of Kepler-47 are designated by letters, with the first planet being designated b and so on. The ordering of designations are identical to the latter designations for candidate planets. [13]

Stellar characteristics

Kepler-47 is a binary star system located about 1,055 parsecs (3,440 light-years) away from Earth. [14] The binary system is composed of a G-type main sequence star (Kepler-47A) and a red dwarf star (Kepler-47B). The stars orbit each other around their barycenter, or center of mass between them, completing one full orbit every 7.45 days. [4] The stars orbit their barycenter from a distance of about 0.084  AU. [4] The stars have 104% and 35% of the Sun's mass, and 96% and 35% of the Sun's radius, respectively. [4] They have surface temperatures of 5636 K and 3357 K. [4] Based on the stellar characteristics and orbital dynamics, an estimated age of 4–5 billion years for the system is possible. [4] In comparison, the Sun is about 4.6 billion years old, [15] and has a temperature of 5772 K. [16]

The primary star is somewhat metal-poor, with a metallicity ([Fe/H]) of about −0.25, or about 56% of the amount of iron and other heavier metals found in the Sun. [4] Both of the stars' luminosities are typical for their kind, with a luminosities of around 84% and 1% of that of the solar luminosity, respectively. [4]

The apparent magnitude of the star system, or how bright it appears from Earth's perspective, is about 15.4. [2] It is too dim to be seen with the naked eye, which can typically detect objects with a magnitude less than 6.5. [17]

Planetary system

Orbital diagram of the Kepler-47 system. The outermost planet is Kepler-47c while the innermost planet is Kepler-47b. The largest planet, Kepler-47d, orbits between Kepler-47 b and c. Kepler-47 System Artist-Impression Overhead.jpg
Orbital diagram of the Kepler-47 system. The outermost planet is Kepler-47c while the innermost planet is Kepler-47b. The largest planet, Kepler-47d, orbits between Kepler-47 b and c.

Prior to the discovery of the Kepler-47 planetary system by Jerome Orosz, his colleagues, as well as astronomers from Tel-Aviv University in 2012, [8] most scientists thought that binary stars with multiple planets could not exist. [5] It was believed that gravitational perturbations caused by the orbiting parent stars would cause any circumbinary planets to collide with each other or be ejected out of orbit, either into one of the parent stars or away from the system. [5] However, this discovery demonstrates that multiple planets can form around binary stars, even in their habitable zones; and while the planets in the Kepler-47 system are unlikely to harbor life, other planets orbiting around binary star systems may be habitable and could support life. [5] Because most stars are binary, the discovery that multi-planet systems can form in such a system has impacted previous theories of planetary formation, and could provide more opportunities for finding potentially habitable exoplanets. [7] [5]

The binary system is known to host three planets, all orbiting close to each other and larger than Earth, with no solid surface. [3] All three of the planets in the Kepler-47 system have a very low density, less than that of Saturn. [18] [19] The densities of the planets are estimated to be around 0.26 g/cm3 to 0.68 g/cm3. [3] The low densities of the planets are unusual for their relatively mild temperatures; planets with such low densities are typically hot jupiters that orbit close to their host stars, being known as so-called puffy planets. [19] [18] Temperate low-density planets like these are thought to be uncommon. [18]

The Kepler-47 planetary system [3]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 2.07+23.70
−2.07  M🜨 		0.2877+0.0014
−0.0011		49.4643+0.0081
−0.0074		0.0210+0.0025
−0.0022		89.752+0.063
−0.045 ° 		3.05±0.04  R🜨
d19.02+23.84
−11.67  M🜨 		0.6992+0.0031
−0.0033		187.366+0.069
−0.051		0.024+0.025
−0.017		90.395+0.009
−0.012 ° 		7.04+0.66
−0.49  R🜨
c 3.17+2.18
−1.25  M🜨 		0.9638+0.0041
−0.0044		303.227+0.062
−0.027		0.044+0.029
−0.019		90.1925+0.0055
−0.0042 ° 		4.65+0.09
−0.07  R🜨
Artist's depiction of the relative sizes of the three planets in the Kepler-47 system. From the left: Kepler-47b; Kepler-47d; and Kepler-47c. Kepler-47 Artist-Impression 20190416.jpg
Artist's depiction of the relative sizes of the three planets in the Kepler-47 system. From the left: Kepler-47b; Kepler-47d; and Kepler-47c.

Kepler-47b is a Neptune class planet and the innermost planet of the Kepler-47 system. It resides close to its parent stars, at a distance of 0.2956 AU. [4] [3] It completes one full orbit around its parent stars in less than 50 days. [5] The equilibrium temperature of Kepler-47b is 442 K, therefore being inhospitable to life. [18] Due to the high equilibrium temperature of Kepler-47b, methane gas in its atmosphere would be broken into other compounds, leading to a thick haze that would cover the planet's atmosphere. [5] It is the smallest planet of the Kepler-47 system, being 3.1 times the size of Earth. [18]

The second planet discovered, Kepler-47c, is a Neptune class planet and the outermost planet, orbiting its parent stars from a distance of 0.989 AU, nearly the distance from Earth to the Sun. [4] It completes one full orbit around its parent stars in about 300 days. [5] Kepler-47c is situated within the habitable zone, with an equilibrium temperature of 241 K. [5] [18] The radius of Kepler-47c is 4.7 times that of Earth, comparable in size to Neptune. [5] [18] Although it is assumed Kepler-47c is not capable of harboring life, it could possibly have a dense atmosphere of water vapor. [5]

An artist's rendition of an exoplanet system, Kepler-47. Artist's concept illustrates Kepler-47, the first transiting circumbinary system.jpg
An artist’s rendition of an exoplanet system, Kepler-47.

The most recently discovered planet in the system, Kepler-47d, was announced as being discovered by astronomer Jerome Orosz and his colleagues at San Diego State University in November 2013. [9] [18] From transit data of the Kepler-47 system from the Kepler space telescope, Orosz's team had noticed one orphan transit signal that lasted for 4.15 hours, [4] [20] and was not attributed to the two previously known planets. [18] [9] Due to the weak transit signals of Kepler-47d, it was not detected earlier in 2012. [18] [3] Only one noticeable transit of Kepler-47d has been detected, [20] thus an additional transit of the planet was needed to confirm its existence. [10] From dynamical simulations, the orbit of Kepler-47d was shown to precess over time, resulting in a four-year period without transits from Kepler-47d. [4] [9] Later studies of the Kepler-47 system led to the confirmation of Kepler-47d, which was announced in April 2019. [10] The discovery of Kepler-47d was unexpected for Orosz's team, as they had expected to find additional planets with more distant orbits. [18] [19] Kepler-47d is the largest planet of the Kepler-47 system, with a radius at least 7 times the radius of Earth (almost the size of Saturn, though its mass is comparable to that of Neptune). [3] It orbits between the planets Kepler-47b and c at a distance of about 0.7 AU, completing an orbit every 187.35 days. [9] [21] Its equilibrium temperature is around 283 K. [18]

See also

Related Research Articles

<span class="mw-page-title-main">Kepler space telescope</span> NASA satellite for exoplanetology (2009–2018)

The Kepler space telescope is a disused space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018.

<span class="mw-page-title-main">Methods of detecting exoplanets</span>

Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of April 2014 have been observed directly, with even fewer being resolved from their host star.

<span class="mw-page-title-main">Circumbinary planet</span> Planet that orbits two stars instead of one

A circumbinary planet is a planet that orbits two stars instead of one. The two stars orbit each other in a binary system, while the planet typically orbits farther from the center of the system than either of the two stars. In contrast, circumstellar planets in a binary system have stable orbits around one of the two stars, closer in than the orbital distance of the other star. Studies in 2013 showed that there is a strong hint that a circumbinary planet and its stars originate from a single disk.

<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 1 September 2023, there are 5,506 confirmed exoplanets in 4,065 planetary systems, with 878 systems having more than one planet. This is a list of the most notable discoveries.

<span class="mw-page-title-main">Kepler-16b</span> Gas giant orbiting Kepler-16 star system

Kepler-16b is an exoplanet. It is a Saturn-mass planet consisting of half gas and half rock and ice, and 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.

<span class="mw-page-title-main">Kepler-16</span> Binary star system in the constellation Cygnus

Kepler-16 is an eclipsing binary star system in the constellation of Cygnus that was targeted by the Kepler spacecraft. Both stars are smaller than the Sun; the primary, Kepler-16A, is a K-type main-sequence star and the secondary, Kepler-16B, is an M-type red dwarf. They are separated by 0.22 AU, and complete an orbit around a common center of mass every 41 days. The system is host to one known extrasolar planet in circumbinary orbit: the Saturn-sized Kepler-16b.

<span class="mw-page-title-main">Planet Hunters</span> Citizen science project to find exoplanets

Planet Hunters is a citizen science project to find exoplanets using human eyes. It does this by having users analyze data from the NASA Kepler space telescope and the NASA Transiting Exoplanet Survey Satellite. It was launched by a team led by Debra Fischer at Yale University, as part of the Zooniverse project.

PH1b, or by its NASA designation Kepler-64b, is an extrasolar planet found in a circumbinary orbit in the quadruple star system Kepler-64. The planet was discovered by two amateur astronomers from the Planet Hunters project of amateur astronomers using data from the Kepler space telescope with assistance of a Yale University team of international astronomers. The discovery was announced on 15 October 2012. It is the first known transiting planet in a quadruple star system, first known circumbinary planet in a quadruple star system, and the first planet in a quadruple star system found. It was the first confirmed planet discovered by PlanetHunters.org. An independent and nearly simultaneous detection was also reported from a revision of Kepler space telescope data using a transit detection algorithm.

<span class="mw-page-title-main">Kepler-47c</span> Goldilocks gas giant orbiting Kepler-47 system

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.

<span class="mw-page-title-main">Kepler-62</span> K-type star in the constellation Lyra

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.

<span class="mw-page-title-main">Kepler-62f</span> Super-Earth orbiting Kepler-62

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 spacecraft. It is located about 980 light-years from Earth in the constellation of Lyra.

<span class="mw-page-title-main">Kepler-47b</span> Circumbinary gas giant exoplanet orbiting the Kepler-47 star system

Kepler-47b is an exoplanet orbiting the binary star system Kepler-47, the innermost 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.

<span class="mw-page-title-main">Habitability of binary star systems</span> Potential conditions for extraterrestrial life in binary star systems

Planets in binary star systems may be candidates for supporting extraterrestrial life. Habitability of binary star systems is determined by many factors from a variety of sources. Typical estimates often suggest that 50% or more of all star systems are binary systems. This may be partly due to sample bias, as massive and bright stars tend to be in binaries and these are most easily observed and catalogued; a more precise analysis has suggested that the more common fainter stars are usually singular, and that up to two thirds of all stellar systems are therefore solitary.

<span class="mw-page-title-main">Kepler-1647b</span> Circumbinary gas giant orbiting the Kepler-1647 star system

Kepler-1647b is a circumbinary exoplanet that orbits the binary star system Kepler-1647, 3,700 light-years (1,100 pc) from Earth in the constellation Cygnus. It was announced on June 13, 2016, in San Diego at a meeting of the American Astronomical Society. It was detected using the transit method, when it caused the dimming of the primary star, and then again of the secondary star blended with the primary star eclipse. The first transit of the planet was identified in 2012, but at the time the single event was not enough to rule out contamination, or confirm it as a planet. It was discovered by the analysis of the Kepler light-curve, which showed the planet in transit.

WASP-47 is a star similar in size and brightness to the Sun about 870 light-years away in the constellation Aquarius. It lies within the Kepler K2 campaign field 3. It was first noticed to have a hot Jupiter exoplanet orbiting every 4 days in 2012 by the Wide Angle Search for Planets (WASP) team. While it was thought to be a typical hot Jupiter system, three more planets were found in 2015: an outer gas giant within the habitable zone, a hot Neptune exterior to the hot Jupiter's orbit and a super-Earth interior to the hot Jupiter's orbit. WASP-47 is the only planetary system known to have both planets near the hot Jupiter and another planet much further out.

<span class="mw-page-title-main">TOI-1338</span> Binary star system in the constellation Pictor

TOI-1338 is a binary star system located in the constellation Pictor, about 1,320 light-years from Earth. It is orbited by two known circumbinary planets, TOI-1338 b, discovered by the Transiting Exoplanet Survey Satellite (TESS) and BEBOP-1c, discovered by the Binaries Escorted By Orbiting Planets project.

References

  1. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 "UCAC4 685-070595". VizieR. 2012. Retrieved 16 April 2019.
  3. 1 2 3 4 5 6 7 8 Orosz, Jerome A.; Welsh, William F.; Haghighipour, Nader; Quarles, Billy; Short, Donald R.; Mills, Sean M.; Sutyal, Suman; Torres, Guillermo; Agol, Eric; Fabrycky, Daniel C. (16 April 2019). "Discovery of a Third Transiting Planet in the Kepler-47 Circumbinary System". The Astronomical Journal. 157 (5): 174. arXiv: 1904.07255 . Bibcode:2019AJ....157..174O. doi:10.3847/1538-3881/ab0ca0. S2CID   118682065.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Orosz, Jerome A.; Welsh, William F.; Carter, Joshua A.; Fabrycky, Daniel C.; Cochran, William D.; Endl, Michael; Ford, Eric B.; Haghighipour, Nader; MacQueen, Phillip J.; Mazeh, Tsevi; Sanchis-Ojeda, Roberto; Short, Donald R.; Torres, Guillermo; Agol, Eric; Buchhave, Lars A.; Doyle, Laurance R.; Isaacson, Howard; Lissauer, Jack J.; Marcy, Geoffrey W.; Shporer, Avi; Windmiller, Gur; Barclay, Thomas; Boss, Alan P.; Clarke, Bruce D.; Fortney, Jonathan; Geary, John C.; Holman, Matthew J.; Huber, Daniel; Jenkins, Jon M.; et al. (2012). "Kepler-47: A Transiting Circumbinary Multi-Planet System". Science. 337 (6101): 1511–4. arXiv: 1208.5489 . Bibcode:2012Sci...337.1511O. doi:10.1126/science.1228380. PMID   22933522. S2CID   44970411.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 "NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars". exoplanets.nasa.gov. NASA. 28 August 2012. Retrieved 2 September 2012. Kepler mission has discovered multiple transiting planets orbiting two suns for the first time
  6. ↑ Orosz, Jerome A.; Welsh, William F.; Carter, Joshua A.; Fabrycky, Daniel C.; Cochran, William D.; Endl, Michael; Ford, Eric B.; Haghighipour, Nader; MacQueen, Phillip J.; Mazeh, Tsevi; Sanchis-Ojeda, Roberto; Short, Donald R.; Torres, Guillermo; Agol, Eric; Buchhave, Lars A.; Doyle, Laurance R.; Isaacson, Howard; Lissauer, Jack J.; Marcy, Geoffrey W.; Shporer, Avi; Windmiller, Gur; Barclay, Thomas; Boss, Alan P.; Clarke, Bruce D.; Fortney, Jonathan; Geary, John C.; Holman, Matthew J.; Huber, Daniel; Jenkins, Jon M.; et al. (28 August 2012). "NASA's Kepler discovers multiple planets orbiting a pair of stars". Science. Sciencedaily.com. 337 (6101): 1511–4. arXiv: 1208.5489 . Bibcode:2012Sci...337.1511O. doi:10.1126/science.1228380. PMID   22933522. S2CID   44970411 . Retrieved 4 November 2012.
  7. 1 2 Quintana, Elisa V.; et al. (November 2006). "Terrestrial planet formation surrounding close binary stars". Icarus. 185 (1): 1–20. arXiv: astro-ph/0607222 . Bibcode:2006Icar..185....1Q. doi:10.1016/j.icarus.2006.06.016. S2CID   17611721.
  8. 1 2 Shamah, David (30 August 2012). "New worlds discovered, courtesy of US-Israel team". The Times of Israel . Retrieved 30 August 2012.
  9. 1 2 3 4 5 "The Confirmation of a Third Planet in the Kepler-47 Circumbinary System" (PDF). 2013.
  10. 1 2 3 "Scientists Fill Out A Circumbinary Planetary System". Institute For Astronomy. 16 April 2019.
  11. ↑ "Mission overview". NASA. 13 April 2015. Retrieved 17 April 2019.
  12. 1 2 Borucki, William J.; et al. (1 February 2011). "Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data" (PDF). The Astrophysical Journal. 736 (1): 19. arXiv: 1102.0541 . Bibcode:2011ApJ...736...19B. doi:10.1088/0004-637X/736/1/19. S2CID   15233153. Archived from the original (PDF) on 21 July 2011. Retrieved 18 September 2019.
  13. ↑ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv: 1012.0707 [astro-ph.SR].
  14. ↑ "Kepler-47". CDS Portal.
  15. ↑ Williams, Matt (22 December 2015). "What is the Life Cycle Of The Sun?". Universe Today . Retrieved 16 September 2019.
  16. ↑ "Sun Fact Sheet". NASA Space Science Data Coordinated Archive. NASA. 23 February 2018. Retrieved 18 September 2019.
  17. ↑ Snyder, Dave (September 2005). "University Lowbrow Astronomers Naked Eye Observer's Guide". University Lowbrow Astronomers. Retrieved 18 September 2019.
  18. 1 2 3 4 5 6 7 8 9 10 11 12 "Discovery Alert: A Third Planet in Kepler-47 System". exoplanets.nasa.gov. NASA. 17 April 2019. Retrieved 17 April 2019.
  19. 1 2 3 Wall, Mike (16 April 2019). "Discovery! 3rd Planet Found in Two-Star 'Tatooine' Star System". Space.com. Retrieved 16 April 2019.
  20. 1 2 Hinse, Tobias C. (15 January 2015). "Predicting a third planet in the Kepler-47 circumbinary system". The Astrophysical Journal. 799 (1): 88. arXiv: 1409.1349 . Bibcode:2015ApJ...799...88H. doi:10.1088/0004-637X/799/1/88. S2CID   118358830.
  21. ↑ "Planet Kepler-47 (AB) d". exoplanet.eu. 17 April 2019. Retrieved 18 April 2019.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.