Kepler-438b

Last updated

Kepler-438b [1] [2] [3]
Exoplanet Comparison Kepler-186 f.png
Approximate size comparison of Kepler-438b (right) with Earth
Discovery
Discovered by Kepler spacecraft
Discovery date2015 [4]
Transit
Orbital characteristics
0.16600 AU (24,833,000 km)
Eccentricity 0.03+0.01
−0.03 [3]
35.23319 d
Inclination 89.860
Star Kepler-438
Physical characteristics
Mean radius
1.12 (± 0.16) R🜨
Temperature 276 K (3 °C; 37 °F)

    Kepler-438b (also known by its Kepler Object of Interest designation KOI-3284.01) is a confirmed near-Earth-sized exoplanet. It is likely rocky. [5] It orbits on the inner edge of the habitable zone of a red dwarf, Kepler-438, about 472.9 light-years (141,8 parsecs) from Earth in the constellation Lyra. [1] [2] It receives 1.4 times our solar flux. [6] 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. [1]

    Contents

    Characteristics

    Mass, radius and temperature

    Kepler-438b is an Earth-sized planet, an exoplanet that has a mass and radius close to that of Earth. It has a radius of 1.12 R🜨, and an unknown mass. It has an equilibrium temperature of 276 K (3 °C; 37 °F), close to that of Earth.

    Host star

    The planet orbits a (M-type) red dwarf star named Kepler-438. The star has a mass of 0.54 M☉ and a radius of 0.52 R☉, both lower than those of the Sun by almost half. It has a surface temperature of 3748 K and is estimated to be about 4.4 billion years old, [3] only 200 million years younger than the Sun [7] and the Sun has a surface temperature of 5778 K. [8]

    The star's apparent magnitude, or how bright it appears from Earth's perspective, is 14.467. Therefore, it is too dim to be seen with the naked eye.

    Orbit and possible moons

    Kepler-438b orbits its parent star once every 35 days and 5 hrs [1] [2] It is likely tidally locked due to its close distance to its star. [9] A search for exomoons by the Hunt for Exomoons with Kepler project around Kepler-438b placed a maximum mass of a hypothetical moon at 29% that of the planet. [10]

    Habitability

    The planet was announced as orbiting within the habitable zone of Kepler-438, a region where liquid water could exist on the surface of the planet. However it has been found that this planet is subjected to powerful radiation activity from its parent star every 100 days, much more violent storms than the stellar flares emitted by the Sun and which would be capable of sterilizing life on Earth. [11]

    Researchers at the University of Warwick say that Kepler-438b is not habitable due to the large amount of radiation it receives. [12] The question of what makes a planet habitable is much more complex than having a planet located at the right distance from its host star so that water can be liquid on its surface: various geophysical and geodynamical aspects, the radiation, and the host star's plasma environment can influence the evolution of planets and life, if it originated. [13] The planet is more likely to resemble a larger and cooler version of Venus.

    Discovery and follow-up studies

    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 50000 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 bunch for follow-up 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-438b occurred roughly every 35 days (its orbital period), it was eventually concluded that a planetary body was responsible for the periodic 35-day transits. The discovery, along with the planetary systems of the stars Kepler-442, Kepler-440 and Kepler-443 were announced on January 6, 2015. [1]

    At nearly 460 light-years (140 pc) distant, Kepler-438b is too far from Earth for either current telescopes, or even the next generation of planned telescopes, to accurately determine its mass or whether it has an atmosphere. The Kepler spacecraft can only focus on a small, fixed region of the sky, but the next generation of planet-hunting space telescopes, such as TESS and CHEOPS, will have more flexibility. Exoplanetary systems, with stars less distant than Kepler 438, can then be studied in tandem with the upcoming James Webb Space Telescope and ground-based observatories like the future Square Kilometer Array. [14]

    Notable Exoplanets – Kepler Space Telescope
    KeplerExoplanets-NearEarthSize-HabitableZone-20150106.png
    Confirmed small exoplanets in habitable zones.
    (Kepler-62e, Kepler-62f, Kepler-186f, Kepler-296e, Kepler-296f, Kepler-438b, Kepler-440b, Kepler-442b)
    (Kepler Space Telescope; 6 January 2015). [1]

    See also

    Related Research Articles

    <span class="mw-page-title-main">Exoplanet</span> Planet outside the Solar System

    An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of the detection occurred in 1992. A different planet, initially detected in 1988, was confirmed in 2003. As of 1 December 2023, there are 5,550 confirmed exoplanets in 4,089 planetary systems, with 887 systems having more than one planet. The James Webb Space Telescope (JWST) is expected to discover more exoplanets, and also much more about exoplanets, including composition, environmental conditions and potential for life.

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

    The Kepler space telescope is a defunct 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">Exomoon</span> Moon beyond the Solar System

    An exomoon or extrasolar moon is a natural satellite that orbits an exoplanet or other non-stellar extrasolar body.

    <span class="mw-page-title-main">Super-Earth</span> Planet with a mass between Earth and Uranus

    A Super-Earth is a type of exoplanet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term.

    <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 December 2023, there are 5,550 confirmed exoplanets in 4,089 planetary systems, with 887 systems having more than one planet. This is a list of the most notable discoveries.

    <span class="mw-page-title-main">Kepler-22b</span> Super-Earth exoplanet orbiting Kepler-22

    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.

    <span class="mw-page-title-main">Kepler-62e</span> Habitable-zone super-Earth planet orbiting Kepler-62

    Kepler-62e is a super-Earth exoplanet 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 from Earth in the constellation of Lyra. 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.

    <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">Hunt for Exomoons with Kepler</span> Space research project

    The Hunt for Exomoons with Kepler (HEK) is a project whose aim is to search for exomoons, natural satellites of exoplanets, using data collected by the Kepler space telescope. Founded by British exomoonologist David Kipping and affiliated with the Center for Astrophysics | Harvard & Smithsonian, HEK submitted its first paper on June 30, 2011. HEK has since submitted five more papers, finding some evidence for an exomoon around a planet orbiting Kepler-1625b in July 2017.

    <span class="mw-page-title-main">Kepler-90h</span> Exoplanet in the constellation Draco

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    <span class="mw-page-title-main">Kepler-138</span> Red dwarf in the constellation Lyra

    Kepler-138, also known as KOI-314, is a red dwarf located in the constellation Lyra, 219 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets transiting their stars.

    <span class="mw-page-title-main">Kepler-186f</span> Terrestrial exoplanet orbiting Kepler-186

    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 spacecraft. It is located about 580 light-years from Earth in the constellation of Cygnus.

    <span class="mw-page-title-main">Kepler-442b</span> Super-Earth orbiting Kepler-442

    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 1,206 light-years (370 pc) from Earth in the constellation of Lyra.

    <span class="mw-page-title-main">Kepler-296e</span> Goldilocks Earth sized exoplanet orbiting Kepler 296

    Kepler-296e is a confirmed super-Earth exoplanet orbiting within the habitable zone of Kepler-296. 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 discovery of the exoplanet on 26 February 2014.

    Kepler-296f is a confirmed super-Earth exoplanet orbiting within the habitable zone of Kepler-296. 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 discovery of the exoplanet on 26 February 2014.

    Kepler-438 is a red dwarf in the constellation Lyra, about 640 light years from Earth. It is notable for its planetary system, which includes Kepler-438b, a possibly Earth-size planet within Kepler-438's habitable zone.

    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.

    <span class="mw-page-title-main">Kepler-1229b</span> Super-Earth orbiting Kepler-1229

    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-442 is a K-type main-sequence star approximately 1,206 light years from Earth in the constellation Lyra. It is located 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 January 6, 2015, along with the notable stars of Kepler-438 and Kepler-440, it was announced that the star has an extrasolar planet orbiting within the habitable zone, named Kepler-442b.

    References

    1. 1 2 3 4 5 6 Clavin, Whitney; Chou, Felicia; Johnson, Michele (6 January 2015). "NASA's Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones". NASA . Retrieved 6 January 2015.
    2. 1 2 3 Sample, Ian (7 January 2015). "Kepler 438b: Most Earth-like planet ever discovered could be home for alien life". The Guardian . Retrieved 7 January 2015.
    3. 1 2 3 Torres, Guillermo; Kipping, David M.; Fressin, Francois; Caldwell, Douglas A.; Twicken, Joseph D.; Ballard, Sarah; Batalha, Natalie M.; Bryson, Stephen T.; Ciardi, David R.; Henze, Christopher E.; Howell, Steve B.; Isaacson, Howard T.; Jenkins, Jon M.; Muirhead, Philip S.; Newton, Elisabeth R.; Petigura, Erik A.; Barclay, Thomas; Borucki, William J.; Crepp, Justin R.; Everett, Mark E.; Horch, Elliott P.; Howard, Andrew W.; Kolbl, Rea; Marcy, Geoffrey W.; McCauliff, Sean; Quintana, Elisa V. (2015). "Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone". The Astrophysical Journal. 800 (2): 99. arXiv: 1501.01101 . Bibcode:2015ApJ...800...99T. doi:10.1088/0004-637X/800/2/99. S2CID   8512655.
    4. ↑ Staff (2015). "Planet Kepler-438 b". The Extrasolar Planets Encyclopaedia . Retrieved 11 January 2015.
    5. ↑ Northon, Karen (19 March 2015). "NASA's Kepler Uncovers More Small Worlds in Habitable Zones". NASA. Retrieved 29 December 2022.
    6. ↑ Gilster, Paul (6 January 2015). "AAS: 8 New Planets in Habitable Zone". Centauri-dreams.org. Retrieved 9 January 2015.
    7. ↑ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today . Retrieved 19 February 2011.
    8. ↑ Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011.
    9. ↑ "Kepler-438b: Astronomers Find Most Earth-Like Exoplanet Yet". Sci News. 8 January 2015. Retrieved 13 June 2016.
    10. ↑ Kipping, D. M.; et al. (2014). "The Hunt for Exomoons with Kepler (HEK). IV. A Search for Moons around Eight M Dwarfs". The Astrophysical Journal. 784 (1): 28–41. arXiv: 1401.1210 . Bibcode:2014ApJ...784...28K. doi:10.1088/0004-637X/784/1/28. S2CID   119305398.
    11. ↑ Perkins, Sid (2015). "Earth-like planet may be not so hospitable after all, thanks to blasts of radiation". Science. doi:10.1126/science.aad7455. ISSN   0036-8075.
    12. ↑ 'Earth-like' Exoplanet Likely Not Habitable
    13. ↑ Lammer, H.; Bredehöft, J. H.; Coustenis, A.; Khodachenko, M. L.; et al. (2009). "What makes a planet habitable?" (PDF). The Astronomy and Astrophysics Review. 17 (2): 181–249. Bibcode:2009A&ARv..17..181L. doi:10.1007/s00159-009-0019-z. S2CID   123220355. Archived from the original (PDF) on 2 June 2016. Retrieved 3 May 2016.
    14. ↑ Siemion, Andrew P.V.; Demorest, Paul; Korpela, Eric; Maddalena, Ron J.; Werthimer, Dan; Cobb, Jeff; Langston, Glen; Lebofsky, Matt; Marcy, Geoffrey W.; Tarter, Jill (3 February 2013). "A 1.1 to 1.9 GHz SETI Survey of the Kepler Field: I. A Search for Narrow-band Emission from Select Targets". Astrophysical Journal. 767 (1): 94. arXiv: 1302.0845 . Bibcode:2013ApJ...767...94S. doi:10.1088/0004-637X/767/1/94. S2CID   119302350.
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