Exoplanets

 

 

 

An exoplanet or extrasolar planet is a planet outside the Solar System.  As of April 1, 2021, there have been 4,1704 confirmed exoplanets in 3,478 star systems, with 770 systems having more than one planet. 

The methods used to detect an exoplanet include transit photometry, radio velocity method, Doppler spectroscopy, and gravitational microlensing. 

The least massive planet, named Draugr, is about twice the mass of the moon.  The most massive planet, named HR 2562, is about 30 times the mass of Jupiter.  

The nearest exoplanets are located 4.2 light-years away and orbit Proxima Centauri, the closest star to the Sun. 

In 1988, the first suspected scientific detection of an exoplanet occurred, but not confirmed.

 In 1990, observations were published that a planet orbited Gamma Cephei.  In 2003, improved techniques allowed the planet’s existence to be confirmed. 

On January 9, 1992, the first confirmation of detection occurred, with an exoplanet revolving around a pulsar (PSR B1257+12).   It is located 2,300 light-years from the Sun in the constellation Virgo.  The pulsar rotates about 161 times per second.  It has 3 known exoplanets.

On October 6, 1995, the first confirmation of an exoplanet orbiting a main-sequence star occurred.   This was detected by Michel Mayor and Didier Queloz of the University of Geneva.  The two shared the 2019 Nobel Prize in Physics with James Peebles who contributed theoretical discoveries in physical cosmology.   They had found a giant planet in a four-day orbit around the nearby star 51 Pegasi.  The star is 50.45 light-years from Earth in the constellation of Pegasus. 

In 1999,  the binary star Upsilon Andromedae became the first main-sequence star known to have multiple planets.  It is 44 light-years away.

By 2000, 50 exoplanets had been discovered.  In 2000, 9 new exoplanets were discovered.  [source: The Iowa Register, Aug 7, 2000, p. 1]

By 2003, Dr. Geoffrey Marcy and his team at the University of California, Berkeley, discovered nearly 60 exoplanets.  By 2003, at least 123 exoplanets were known. 

In 2004, for the first time, an exoplanet was discovered by an international network of amateur astronomers.  The exoplanet was found in the constellation Lyra, 500 light-years away.   The discovery was confirmed by the Keck I telescope in Hawaii.  The new planet, known as TrES-1. Is a hot, Jupiter-sized gas giant orbiting 4 million miles from a star in Lyra.  This exoplanet orbits its star in 72 hours.  [source:  Santa Clara Sentinel, Aug 26, 2004, p. 24] 

In 2004, astronomers made the first discovery of a multiple planet system beyond the Solar System.  [source: Tyrone (Pennsylvania) Daily Herald, Aug 31, 2004, p. 6] 

By 2006, 160 exoplanets had been discovered.  

In 2006, the smallest exoplanet discovered was found in the constellation Sagittarius orbiting a star 20,000 light-years away..  It is the smallest and most distant exoplanet discovered so far.  The newly found exoplanet is about 5.5 times the mass of the Earth, but much smaller than the Jupiter-size exoplanets discovered in the past.  [source: The Index-Journal (Greenwood, SC), Jan 20, 2006, p. 6] 

By May 2007, 28 new exoplanets were discovered, making the total number of exoplanetr discovered so far to be 236.  [source: Indiana Gazette (Indiana, PA) May 29, 2007, p. 8]

In November 2007, 5 exoplanets were discovered orbiting the nearby star 55 Cancri in the constellation Cancer.  55 Cancri is a sun-like star 41 light-years away.  The number of exoplanets discovered to date was 250.  [source: The Herald (Jasper, IN), Nov 7, 2007, p. 20] 

By 2008, over 300 exoplanets had been discovered.  Two ground-based telescopes and photos from the Hubble Space Telescope may have taken the first photos of an exoplanet that circles the star Fomulhaut.  [source: The Herald (Jasper, IN), Nov 14, 2008, p. 22]

In August 2003, the NASA Spitzer Space Telescope was launched and was used to discover an exoplanet.

In March 2009, the planet-hunting Kepler spacecraft was launched.  It examined 150,000 stars, looking for exoplanets.  It measures the regular, tiny dips in the starlight.  The starlight must dip three times, showing three obits, before Kepler marks a planetary discovery.  Each planet discovered by Kepler must be confirmed by other methods before it is considered an exoplanet.  The Kepler mission was rejected 4 times before it was approved and launched.

In 2009, two exoplanets were discovered orbiting the start Gliese, in the constellation Libra, 20.5 light-years away.  One of them was the smallest exoplanet found so far, about 1.9 times the size of the Earth.  Nearly 350 exoplanets have been discovered so far.  [source: The Herald (Jasper, IN), Apr 22, 2009, p. 17]

By the end of 2009, over 400 exoplanets had been discovered. 

By 2010, over 500 exoplanets had been discovered.  700 more were awaiting confirmation.  

In October 2010, it was announced that the first Earth-sized exoplanet was found that appeared to be potentially habitable.  [source: The Progress-Index (Petersburg, VA) Nov 14, 2010, p. 12]

By August 2011, 1,235 exoplanets had been discovered.  Much of the new discoveries came from NASA’s Kepler planet-hunting spacecraft mission.

By 2012, 2,300 exoplanets had been discovered.  About 200 of them were roughly Earth-sized. 

In July 2012, University of Central Florida scientists discovered the closes Earth-sized exoplanet (named UCF 1.01) ever discovered.  It orbits a red dwarf star called GJ 436 in the constellation Leo, 33 light-years away.  The exoplanet is about 2/3 the size of Earth.  The red dwarf is about half the size of the Sun.  The exoplanet revolves around it aver 1.4 days.  The exoplanet was discovered with the help of the NASA Spitzer Space Telescope.  UCF 1.01 is the first exoplanet actually discovered by the Spitzer Space Telescope.  [source: The Herald (Jasper, IN), July 19, 2012, p. 15]

In October 2012, a group of amateur astronomers affiliated with Planethunters.org, discovered a Neptune-sized gas giant exoplanet called PH1.  The exoplanet orbits two stars of a four-star system.  The exoplanet orbits the two stars every 138 days.  PH1 is the first exoplanet found in a system of 4 stars.  Only 6 exoplanets are known to orbit two stars.  [source: The Herald (Jasper, IN), Oct 16, 2012, p. 18] 

In 2013, the Kepler Space Telescope found the smallest exoplanet yet.  The exoplanet is smaller than Mercury and orbits a sun-like star (Kepler-37) about 210 light-years away.  So far, Kepler has detected 2,740 possible exoplanets.   A total of 3 exoplanets were found orbiting Kepler-37.  [source: The Herald (Jasper, IN), Feb 21, 2013, p. 15] 

In May 2013, the Kepler Space Telescope became disabled when a crucial reaction gyroscope wheel ceased to function.  This put a stop on exoplanet discovery as the spacecraft was put in safe mode.  It was finally deactivated on Nov 15, 2018 after its reaction control system fuel was depleted.  Kepler had identified 3.601 candidate planets and 246 confirmed exoplanets since 2009.  [source: The Herald (Jasper, IN), May 16, 2013, p. 32]

In 2014, researchers used the pressure of solar radiation to stabilize Kepler.  With two functional wheels and the force of the Sun , the spacecraft could once again focus on distant stars.  The reborn project was given the name K2.

On February 26, 2014, NASA announced the discovery of 715 newly verified exoplanets around 305 stars.  The exoplanets were discovered with the help of data from the Kepler Space Telescope, launched in 2009.  961 exoplanets found by Kepler had now been confirmed.  [source: The Herald (Jasper, IN), Feb 27, 2014, p. 17]

In April 2014, astronomers discovered the first definitive Earth-sized exoplanet (Kepler=-186f) that orbits in a habitable zone where water could exist in liquid form.  Its parent star, Kepler-186, is a red dwarf 490 light-years away in the constellation Cygnus.  1,800 exoplanets had been confirmed up to this time.  [source: The Herald (Jasper, IN), April 18, 2014, p. 28]

In September 2014, a Neptune-sized exoplanet named HAT-P-11b was discovered that had water vapor.  It is the smallest planet yet known to host water in its atmosphere.  The exoplanet is 120 light-years away in he constellation Cygnus.  The exoplanet circles its star every 5 days.  [source: The Herald (Jasper, IN), Sep 25, 2014, p. 15] 

In July 2015, NASA discovered an exoplanet orbiting Kepler-452, about 1.402 light-years away in the constellation Cygnus.  The exoplanet is a near-Earth-size planet orbiting the habitable zone of this star.  It orbits its star at about the same distance that Earth orbits the Sun.  Its home star is similar to our Sun.  This is the nearest thing to another Earth-sun twin system.  [source: The Herald (Jasper, IN), July 24, 2015, p. 15]

In the spring of 2016, three Earth-sized exoplanets were discovered orbiting an ultra-cool dwarf star (Trappist-1) 36 light-years away.  It’s the first time exoplanets have been found around this type of star.  The dwarf star is about the size of Jupiter in the constellation Aquarius.  It was later discovered that there are 7 exoplanets orbiting this star.  [source: The Herald (Jasper, IN), May 3, 2016, p. 13]

In 2016, an exoplanet (Proxima b) was discovered orbiting Proxima Centauri, the nearest star to our solar system, 4.22 light-years away.  The exoplanet is 4.6 million miles from it red dwarf star.  It circles its star in 11 days.  Proxima b is more than 50 trillion miles closer than the previous closest potentially habitable exoplanet.  The total number of exoplanets discovered up to this point is 3,000.  40 of them seem to be in the habitable zone.  [source: The Index Journal (Greenwood, SC) Aug 25, 2016]

In 2017, seven Earth-sized exoplanets were found orbiting a single nearby star.  The cluster of exoplanets is less than 40 light-years away in the constellation Aquarius.  The exoplanets circle around a dim dwarf star called Trappist-1, which is about the size of Jupiter.  Astronomers have confirmed 3,600 exoplanets up to this date.  [source: The Herald (Jasper, IN), Feb 23, 2017, p. 13]

In 2017, a star system with 8 exoplanets was discovered around Kepler 90.  The discovery was done by a neural network artificial intelligence machine that had to learn by example.  It churned through 14 billion data points to detect the 8 exoplanets.  [source: The Herald (Jasper, IN), Dec 15, 2017, p. 18] 

In February 2018, researchers using the Chandra X-ray Observatory found evidence of exoplanets in a distant galaxy. 

By 2018, 3,700 exoplanets had been confirmed, with another 4,500 exoplanets to be verified. 

On April 18, 2018, the Transiting Exoplanet Survey Satellite (TESS) was launched to look for exoplanets.  It scans the entire sky and uses the transit method to detect exoplanets.  [source: The Herald (Jasper, IN), Apr 21, 2018, p. 6] 

By 2019, over 4,000 exoplanets have been found in the Milky Way galaxy. 

In 2019, an earth-sized exoplanet (K2-18b) was found in the habitable zone of a nearby star.  The star is 110 light-years away in the constellation Leo.  It was discovered from data from the Transiting Exoplanet Survey Satellite (TESS). [sources: Kopparapu, “Earth-Sized Planet Found in the Habitable Zone of a Nearby Star,” Live Science, Jan 7, 2020 and The Herald (Jasper, IN), Sep 16, 2019, p. 10]

In 2019, Michel Mayor and Didier Queloz, won the Nobel Prize in Physics for their discovery of 51 Pegasi B exoplanet.  [source: The Herald (Jasper, IN), Oct 8, 2019, p. 11] 

In 2019, teenage Wolf Cukier, age 17, discovered an exoplanet, called TOI 1338b.  He used the TESS data to discover the exoplanet, which is 7 times larger than Earth and orbiting two stars.  [source: The Herald (Jasper, IN), Jan 20, 2020, p. 10]

As of April 5, 2021, TESS has identified 2.601 candidate exoplanets, of which 122 have been confirmed so far.