Thursday, May 12, 2016

1284 Newly Validated Planets

Figure 1: Artist's impression of an exoplanet.

Morton et al. (2016) present calculations of the astrophysical false positive probability (FPP) for every Kepler object of interest (KOI) detected by NASA's planet-hunting Kepler space telescope. Out of 7056 KOIs, 1935 KOIs have FPP of less than 0.01, validating them as true planets with a confidence level better than 99 percent. Among them, 1284 KOIs have not been validated or confirmed previously. These 1284 newly validated planets more than doubles the number of confirmed Kepler exoplanets and brings the total number of known exoplanets to well over 3000.

Of these 1284 newly validated planets, over 500 of them are believed to be rocky planets. Among them, 9 planets are potentially habitable because they are small enough (i.e. they are not gas-giant planets) and appear to be situated within the habitable zones of their host stars. These potentially habitable planets are between 1 to 2 times the radius of Earth, and they receive between one-third to 1.5 times the amount of flux Earth gets from the Sun.

Figure 2: Properties of the 9 KOIs validated by Morton et al. (2016) that lie within the habitable zones of their host stars. Morton et al. (2016)

Figure 3: Periods and radii of candidate and confirmed KOIs. Blue circles represent confirmed KOIs. Orange circles represent candidate KOIs, and they are shaded by false positive probability (FPP), with a transparent circle representing a high FPP. Morton et al. (2016)

Morton et al. (2016), "False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives", arXiv:1605.02825 [astro-ph.EP]