A newly discovered exoplanet is a real explosion of the past.
Astronomers have just confirmed the existence of KOI-5Ab, which was originally marked as a potential planet by NASA pioneers Kepler Space Telescope Back in 2009.
The elusive alien world is the second “candidate” identified by Kepler, who searches for planets in two different missions From 2009 to 2018. Kepler used the “transit method” to discover from the perspective of the spacecraft that the alien world passed over the face of its host star and caused a significant decrease in brightness.
This work is very fruitful.Of the approximately 4,300 known areas, nearly two-thirds Exoplanet It was discovered by Kepler, and analysis of the huge data set of the telescope continues to bring new discoveries.
More than a decade ago, KOI-5Ab crossed the crack, partly due to data flooding. The Kepler team found a clear transit signal, which belongs to a planet about the size of Neptune, which revolves around a sun-like star every five days. This star and apparent planet are located in the constellation Cygnus, about 1,800 light years from Earth.
But further investigation revealed that the parent star has a companion, making analysis more difficult. There are many other candidates to be reviewed.
Therefore, David Ciardi, chief scientist of NASA’s Exoplanet Science Institute at the Infrared Processing and Analysis Center of the California Institute of Technology in Pasadena, said: “KOI-5Ab was soon abandoned. , Mainly because it has become complicated.” A press conference was held on Monday (January 11) at the 237th meeting of the American Astronomical Society (AAS).
Indeed, KOI-5Ab was more complicated than the researchers realized at the time. By 2014, Ciardi and other scientists had determined that the KOI-5 system actually had three stars. It is not clear whether KOI-5Ab actually exists, or whether the 2009 signal was generated by a companion star.
Thanks to Kepler’s successor, NASA’s successor, KOI-5Ab has received attention again Transit planetary observation satellite (TESS) was launched in 2018. TESS also discovered a signal in the KOI-5 system that was generated by a potential planet whose orbital period is five Earth days.
“I thought to myself,’I still remember this goal,'” Jardi Said in the statement.
Therefore, he carefully studied all the information on the system-Kepler and TESS transit observation data, as well as radial velocity data collected by ground instruments such as the Keck Observatory in Hawaii. (Radial velocity measurement quantifies how much a planet drags on its parent star under gravity. This work can reveal the approximate mass of an exoplanet, and transit observations can give a rough idea of its size.)
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Taken together, the data confirms that KOI-5Ab is indeed a planet, whose mass is about half that of Saturn. Ciardi detailed the new research at the AAS meeting on Monday and also revealed other details of the KOI-5 system. For example, the main star that KOI-5Ab orbits (star A) has a close relative (star B); this duo orbits each other once every 30 Earth years. The third star (C star) in the system is farther away, rotating around the AB pair every 400 years.
In addition, the researchers say that the orbital plane of KOI-5Ab is not aligned with the orbit of star B, which suggests that the star may have given the earth gravity at some point in the history of the system. (Stars and their planets are made up of the same gas and dust clouds, so their orbital planes usually match initially.)
KOI-5Ab is far from the first planet Found in a multi-star system. However, for reasons that scientists do not yet understand, such systems seem to be less likely to carry planets than single-star solar systems like ours.
Jardi said: “Star companions may partially inhibit the formation of planets.” “We still have a lot of things about how and when planets form in multi-star systems and their properties compared to planets in single star systems. Question. By studying the KOI-5 system in more detail, maybe we can gain insight into how the universe makes planets.”
Mike Wall (Mike Wall) is “outside“(Grand Central Press, 2018; Karl Tate illustration), this is a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook .