Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2023 September 20 [2]An artist's illustration pictures a cloudy red planet orbiting a distant red star. Near the exoplanet is a moon. Please see the explanation for more detailed information. Methane Discovered on Distant Exoplanet Illustration Credit: [3]Ahmad Jabakenji ([4]ASU Lebanon, [5]North Star Space Art); Data: [6]NASA, [7]ESA, [8]CSA, [9]JWST Explanation: Where else might life exist? One of humanity's [10]great outstanding questions, locating planets where extrasolar life might survive took a step forward in 2019 with the discovery of a significant amount of water vapor in the atmosphere of distant exoplanet [11]K2-18b. The planet and its parent star, [12]K2-18, lie about 124 light years away toward the constellation of the [13]Lion ([14]Leo). The [15]exoplanet is significantly larger and more massive than our Earth, but orbits in the [16]habitable zone of its home star. K2-18, although more red than our Sun, shines in [17]K2-18b's sky with a brightness similar to the [18]Sun in Earth's sky. The 2019 [19]discovery of atmospheric water was made in data from three space telescopes: [20]Hubble, [21]Spitzer, and [22]Kepler, by noting the absorption of water-vapor colors when the [23]planet moved in front of the star. Now in 2023, [24]further observations by the [25]Webb Space Telescope in [26]infrared light have uncovered evidence of other life-indicating molecules -- including [27]methane. The featured illustration imagines exoplanet [28]K2-18b on the far right orbited by a moon (center), which together orbit a [29]red dwarf star depicted on the lower left. Tomorrow's picture: space tag __________________________________________________________________ [30]< | [31]Archive | [32]Submissions | [33]Index | [34]Search | [35]Calendar | [36]RSS | [37]Education | [38]About APOD | [39]Discuss | [40]> __________________________________________________________________ Authors & editors: [41]Robert Nemiroff ([42]MTU) & [43]Jerry Bonnell ([44]UMCP) NASA Official: Phillip Newman [45]Specific rights apply. [46]NASA Web Privacy Policy and Important Notices A service of: [47]ASD at [48]NASA / [49]GSFC, [50]NASA Science Activation & [51]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2309/ExoplanetJ2_Jabakenji_5940.jpg 3. mailto: a.jabakenji at gmail.com 4. https://www.instagram.com/asu_lebanon/ 5. https://www.instagram.com/north_star_space_art/ 6. https://www.nasa.gov/ 7. https://www.esa.int/ 8. https://www.asc-csa.gc.ca/eng/ 9. https://webb.nasa.gov/ 10. https://apod.nasa.gov/debate/debate100th.html 11. https://en.wikipedia.org/wiki/K2-18b 12. https://en.wikipedia.org/wiki/K2-18 13. http://ae01.alicdn.com/kf/HTB1wvWmKxSYBuNjSspjq6x73VXay.jpg_q50.jpg 14. https://en.wikipedia.org/wiki/Leo_(constellation) 15. https://apod.nasa.gov/apod/ap190710.html 16. https://www.nasa.gov/ames/kepler/habitable-zones-of-different-stars 17. https://www.spacetelescope.org/videos/heic1916a/ 18. https://apod.nasa.gov/apod/ap150512.html 19. https://nouvelles.umontreal.ca/en/article/2019/09/11/water-detected-on-an-exoplanet-located-in-its-star-s-habitable-zone/ 20. https://hubblesite.org/mission-and-telescope/the-telescope 21. https://www.nasa.gov/mission_pages/spitzer/main/index.html 22. https://www.nasa.gov/mission_pages/kepler/spacecraft/index.html 23. http://www.planetary.org/explore/space-topics/exoplanets/transit-photometry.html 24. https://arxiv.org/abs/2309.05566 25. https://www.nasa.gov/mission_pages/webb/main/index.html 26. https://science.nasa.gov/ems/07_infraredwaves 27. https://science.nasa.gov/news-articles/methane-stinks-earth-mars-and-beyond 28. https://www.nasa.gov/goddard/2023/webb-discovers-methane-carbon-dioxide-in-atmosphere-of-k2-18b 29. https://en.wikipedia.org/wiki/Red_dwarf 30. https://apod.nasa.gov/apod/ap230919.html 31. https://apod.nasa.gov/apod/archivepix.html 32. https://apod.nasa.gov/apod/lib/apsubmit2015.html 33. https://apod.nasa.gov/apod/lib/aptree.html 34. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 35. https://apod.nasa.gov/apod/calendar/allyears.html 36. https://apod.nasa.gov/apod.rss 37. https://apod.nasa.gov/apod/lib/edlinks.html 38. https://apod.nasa.gov/apod/lib/about_apod.html 39. https://asterisk.apod.com/discuss_apod.php?date=230920 40. https://apod.nasa.gov/apod/ap230921.html 41. http://www.phy.mtu.edu/faculty/Nemiroff.html 42. http://www.phy.mtu.edu/ 43. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 44. http://www.astro.umd.edu/ 45. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 46. https://www.nasa.gov/about/highlights/HP_Privacy.html 47. https://astrophysics.gsfc.nasa.gov/ 48. https://www.nasa.gov/ 49. https://www.nasa.gov/centers/goddard/ 50. https://science.nasa.gov/learners 51. http://www.mtu.edu/