{"id":4732,"date":"2025-04-22T11:42:00","date_gmt":"2025-04-22T09:42:00","guid":{"rendered":"https:\/\/sphe.astro.cz\/exoplanets\/"},"modified":"2026-08-28T02:13:55","modified_gmt":"2026-08-28T00:13:55","slug":"exoplanets","status":"publish","type":"page","link":"https:\/\/sphe.astro.cz\/en\/exoplanets\/","title":{"rendered":"Exoplanets"},"content":{"rendered":"\t\t
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Exoplanets \u2014 planets orbiting stars outside our Solar System \u2014 represent one of the most dynamically developing branches of modern astronomy. Their study contributes fundamentally to our understanding of the formation and evolution of planetary systems, the diversity of planetary environments, and the conditions that may lead to the existence of life. And because an exoplanet transit can now be measured even by an amateur telescope, observers from our section also have a firm place in this field. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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An artist's impression of the exoplanet 51 Pegasi b \u2014 a hot gas giant that orbits its star in the constellation of Pegasus once every four days. Twenty years after its discovery, star light reflected directly from the planet was captured for the first time. Credit: ESO\/M. Kornmesser\/Nick Risinger (skysurvey.org), CC BY 4.0. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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History of Exoplanet Research<\/strong><\/h4>

The idea of the existence of planets around other stars has appeared since antiquity, but the first scientific attempts at their detection did not come until the 20th century \u2014 and some of the earlier reports were later refuted. Surprisingly, the very first confirmed exoplanets were not found around a Sun-like star: in 1992, radio astronomers detected them around the pulsar PSR B1257+12, a remnant of a supernova explosion. <\/p>

The real breakthrough occurred in 1995, when Michel Mayor and Didier Queloz announced the discovery of the planet 51 Pegasi b \u2014 the first confirmed exoplanet orbiting a Sun-like star. This hot gas giant, which orbits its star once every four days, overturned the notion that alien planetary systems must look like our own. For this discovery, both astronomers received the Nobel Prize in Physics in 2019. <\/p>

An era of rapid growth in discoveries followed, particularly thanks to the Kepler mission (2009\u20132018), which revealed thousands of exoplanet candidates. Currently, we are cataloging more than six thousand confirmed exoplanets, and it is becoming clear that our Solar System is not unique \u2014 planetary systems are a common phenomenon in the Galaxy. Attention is therefore shifting from discovery itself to the detailed characterization of the physical and chemical properties of these worlds. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Principle of the transit method. When an exoplanet (positions 1\u20133) passes in front of its star's disk, it obscures a small part of its surface, and the star's brightness drops slightly for a moment. The size of the planet can be determined from the depth of the drop, and the length of its \"year\" from the repetition of transits. For a Jupiter-sized planet, the drop is roughly one percent; for an Earth-sized planet, it is a mere fraction of a per mille \u2014 the depth is therefore enlarged in the diagram for clarity. Schematic representation. Credit: SPHE \u010cAS. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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How We Discover Exoplanets<\/h2>\t\t\t\t<\/div>\n\t\t\t\t
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An exoplanet is defined as a planet that orbits a star other than the Sun.<\/strong> These objects can be very diverse \u2013 from giant gas planets similar to Jupiter, to “super-Earths” with several times the mass of Earth, to small rocky planets similar to Mars.<\/p>

However, their detection is extremely challenging, as they are immensely faint compared to stars and are close to sources of intense radiation. The main observation methods include: <\/p>