An abundance of small exoplanets around stars with a wide range of metallicities

Buchhave, Lars A.; Latham, David W.; Johansen, Anders; Bizzarro, Martin; Torres, Guillermo; Rowe, Jason F.; Batalha, Natalie M.; Borucki, W. J.; Brugamyer, Erik; Caldwell, Caroline; Bryson, Stephen T.; Ciardi, David R.; Cochran, William D.; Endl, Michael; Esquerdo, Gilbert A.; Ford, Eric B.; Geary, John C.; Gilliland, Ronald L.; Hansen, T.; Isaacson, Howard; Laird, John B.; Lucas, P. W.; Marcy, Geoffrey W.; Morse, Jon A.; Robertson, Paul; Shporer, Avi; Stefanik, R. P.; Still, M.; Quinn, Samuel N.

doi:10.1038/nature11121

Cited by 691 publications

(807 citation statements)

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“…In the last four years, the Kepler mission yielded over 4000 exoplanet candidates, most of them with sizes smaller than Neptune and down to Earth-sized planets. Such small planets (Super Earths) have been shown to be abundant and even to constitute the majority of exoplanets (Buchhave et al, 2012;Batalha et al, 2013). Further work has demonstrated that such planets are often found within the Habitable Zone (HZ) of their host star.…”

Section: Prevalence Of Earthlike Planets Outside Of the Solar Systemmentioning

confidence: 99%

The potential of planets orbiting red dwarf stars to support oxygenic photosynthesis and complex life

Gále

Wandel

2016

International Journal of Astrobiology

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We review and reassess the latest findings on the existence of extra-solar system planets and their potential of having environmental conditions that could support Earth-like life. Within the last two decades, the multi-millennial question of the existence of extra-Solarsystem planets has been resolved with the discovery of numerous planets orbiting nearby stars, many of which are Earth-sized (and some even with moderate surface temperatures).Of particular interest in our search for clement conditions for extra-solar system life are planets orbiting Red Dwarf (RD) stars, the most numerous stellar type in the Milky Way galaxy. We show that including RDs as potential life supporting host stars could increase the probability of finding biotic planets by a factor of up to a thousand, and reduce the estimate of the distance to our nearest biotic neighbor by up to 10. We argue that multiple star systems need to be taken into account when discussing habitability and the abundance of biotic exoplanets, in particular binaries of which one or both members are RDs. Early considerations indicated that conditions on RD planets would be inimical to life, as their Habitable Zones (where liquid water could exist) would be so close as to make planets tidally locked to their star. This was thought to cause an erratic climate and expose life forms to flares of ionizing electro-magnetic radiation and charged particles. Moreover, it has been argued that the lesser photon energy of the radiation of the relatively cool RDs would not suffice for Oxygenic Photosynthesis (OP) and other related energy expending reactions. Recent calculations show that these negative factors are less severe than originally thought. Numerous authors suggest that OP on RD planets may evolve to utilize photons in the infrared. We however argue, by analogy to the evolution of OP and the environmental

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Section: Prevalence Of Earthlike Planets Outside Of the Solar Systemmentioning

confidence: 99%

The potential of planets orbiting red dwarf stars to support oxygenic photosynthesis and complex life

Gále

Wandel

2016

International Journal of Astrobiology

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“…In fact, from examination of the ∼150000 stars in the target list of the Kepler Mission it can be asserted that the fraction of stars showing likely planetary transits is a few per cent. No particular requirement for host star composition appears required for planetary formation (Buchave et al, 2012). …”

Section: Introductionmentioning

confidence: 99%

Analysis of selected Kepler Mission planetary light curves

Rhodes

Budding

2014

Astrophys Space Sci

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We have modified the graphical user interfaced close binary system analysis program CurveFit to the form WinKepler and applied it to 16 representative planetary candidate light curves found in the NASA Exoplanet Archive (NEA) at the Caltech website http://exoplanetarchive.ipac.caltech.edu, with an aim to compare different analytical approaches. WinKepler has parameter options for a realistic physical model, including gravity-brightening and structural parameters derived from the relevant Radau equation. We tested our best-fitting parameter-sets for formal determinacy and adequacy.A primary aim is to compare our parameters with those listed in the NEA. Although there are trends of agreement, small differences in the main parameter values are found in some cases, and there may be some relative bias towards a 90 • value for the NEA inclinations. These are assessed against realistic error estimates.Photometric variability from causes other than planetary transits affects at least 6 of the data-sets studied; with small pulsational behaviour found in 3 of those. For the false positive KOI 4.01, we found that the eclipses could be modelled by a faint background clas- Our empirical checks of limb-darkening, in the cases of KOI 1.01 and 12.01, revealed that the assigned stellar temperatures are probably incorrect. For KOI 13.01, our empirical mass-ratio differs by about 7% from that of Mislis and Hodgkin (Mon. Not. R. Astron. Soc. 422:1512Soc. 422: ,2012, who neglected structural effects and higher order terms in the tidal distortion. Such detailed parameter evaluation, additional to the usual main geometric ones, provides an additional objective for this work.

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“…They reported an asteroseismically determined stellar radius R * = 1.081±0.019 R e , stellar mass M * = 1.069±0.048 M e , and surface gravity log g = 4.399±0.012. Additionally, Huber et al (2013) use Stellar Parameter Classification (SPC, Buchhave et al 2012Buchhave et al , 2014 on spectra from Keck-HIRES (Vogt et al 1994), the TRES spectrograph on the 1.5 m at Whipple Observatory (Furesz 2008) and the Tull spectrograph on the 2.5 m at McDonald Observatory (Tull et al 1995), to obtain a metallicity of [Fe/H] = 0.350±0.101 and effective temperature T eff = 5739±75 K. McQuillan et al (2013) searched for the stellar rotation period of KOI-273 in the autocorrelation function of the Kepler photometry and were unable to detect it.…”

Section: Introductionmentioning

confidence: 99%

The Kepler-454 System: A Small, Not-Rocky Inner Planet, a Jovian World, and a Distant Companion

Gettel

Charbonneau

Dressing

et al. 2016

ApJ

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Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687±50 K, its metallicity to be [m/H] = 0.32±0.08, and the projected rotational velocity to be v sin i<2.4 km s −1 . We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be M 1.028 0.03 0.04 -+  , the radius to be 1.066±0.012 R e , and the age to be 5.25 1.39Gyr. We estimate the radius of the 10.6 day planet as 2.37±0.13 R ⊕ . Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8±1.4 M ⊕ . We also detect two additional nontransiting companions, a planet with a minimum mass of 4.46±0.12 M J in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 M J . The 12 exoplanets with radii <2.7 R ⊕ and precise mass measurements appear to fall into two populations, with those <1.6 R ⊕ following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76±0.73 g cm −3 , Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas.

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An abundance of small exoplanets around stars with a wide range of metallicities

Cited by 691 publications

References 25 publications

The potential of planets orbiting red dwarf stars to support oxygenic photosynthesis and complex life

The potential of planets orbiting red dwarf stars to support oxygenic photosynthesis and complex life

Analysis of selected Kepler Mission planetary light curves

The Kepler-454 System: A Small, Not-Rocky Inner Planet, a Jovian World, and a Distant Companion

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