(Abstract)One bottleneck for the exploitation of data from the Kepler mission for stellar astrophysics and exoplanet research has been the lack of precise radii and evolutionary states for most of the observed stars. We report revised radii of 177,911 Kepler stars derived by combining parallaxes from Gaia Data Release 2 with the DR25 Kepler Stellar Properties Catalog. The median radius precision is ≈ 8%, a typical improvement by a factor of 4-5 over previous estimates for typical Kepler stars. We find that ≈ 67% (≈ 120,000) of all Kepler targets are main-sequence stars, ≈ 21% (≈ 37,000) are subgiants, and ≈ 12% (≈ 21,000) are red giants, demonstrating that subgiant contamination is less severe than some previous estimates and that Kepler targets are mostly main-sequence stars. Using the revised stellar radii, we recalculate the radii for 2123 confirmed and 1922 candidate exoplanets. We confirm the presence of a gap in the radius distribution of small, close-in planets, but find that the gap is mostly limited to incident fluxes > 200F⊕ and its location may be at a slightly larger radius (closer to ≈ 2R⊕) when compared to previous results. Further, we find several confirmed exoplanets occupying a previously-described "hot super-Earth desert" at high irradiance, show the relation between gas-giant planet radius and incident flux, and establish a bona-fide sample of eight confirmed planets and 30 planet candidates with Rp < 2R⊕ in circumstellar "habitable zones" (incident fluxes between 0.25--1.50 F⊕). The results presented here demonstrate the potential for transformative characterization of stellar and exoplanet populations using Gaia data.
The observatory in Canada may have already found clues to one of the newest mysteries in astronomy.
The German Space Agency (DLR) has opened a new simulation facility at its Planetary Spectroscopy Laboratory (PSL) in Berlin. The facility could help researchers better understand the surface of Venus hidden behind the planet's dense atmosphere.
Scientists have identified a group of planets outside our solar system where the same chemical conditions that may have led to life on Earth exist.The researchers, from the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology (MRC LMB), found that the chances for life to develop on the surface of a rocky planet like Earth are connected to the type and strength of light given off by its host star.Their study, published in the journal Science Advances, proposes that stars which give off sufficient ultraviolet (UV) light could kick-start life on their orbiting planets in the same way it likely developed on Earth, where the UV light powers a series of chemical reactions that produce the building blocks of life.
Forty-four planets in solar systems beyond our own have been unveiled in one go, dwarfing the usual number of confirmations from extrasolar surveys, which is typically a dozen or less. The findings will improve our models of solar systems and may help researchers investigate exoplanet atmospheres. Novel techniques developed to validate the find could hugely accelerate the confirmation of more extrasolar planet candidates.An international team of astronomers pooled data from U.S. space agency NASA's Kepler and the European Space Agency (ESA)'s Gaia space telescopes, as well as ground-based telescopes in the U.S. Alongside John Livingston, lead author of the study and a graduate student at the University of Tokyo, the team's combined resources led to the confirmed existence of these 44 exoplanets and described various details about them.
Fornax UCD3 is a part of a Fornax galaxy cluster and belongs to a very rare and unusual class of galaxies - ultracompact dwarfs. The mass of such dwarf galaxies reaches several dozen millions of solar masses and the radius, typically, does not exceed three hundred light years. This ratio between mass and size makes UCDs the densest stellar systems in the Universe."We have discovered a supermassive black hole in the center of Fornax UCD3. The black hole mass is 3.5 million that of the Sun, similar to the central black hole in our own Milky Way" explained Anton Afanasiev, the first author of the article, a student of the department of the Faculty of Physics, MSU.
A lack of new missions keeps scientists guessing on what shaped the planet’s surface
Exoplanets, planets in other solar systems, can orbit very close to their host stars. When the host star is much hotter than the sun, the exoplanet becomes as hot as a star. The hottest "ultra-hot" planet was discovered last year by American astronomers. Today, an international team led by researchers from the University of Geneva (UNIGE), who collaborated with theoreticians from the University of Bern (UNIBE), Switzerland, discovered the presence of iron and titanium vapours in the atmosphere of this planet. The detection of these heavy metals was made possible by the surface temperature of the planet, which reaches more than 4000 degrees. This discovery is published in the journal Nature.
Scientists have shown that water is likely to be a major component of those exoplanets (planets orbiting other stars) which are between two to four times the size of Earth. It will have implications for the search of life in our Galaxy. The work is presented at the Goldschmidt Conference in Boston.
Li Zeng continued, "Our data indicate that about 35% of all known exoplanets which are bigger than Earth should be water-rich. These water worlds likely formed in similar ways to the giant planet cores (Jupiter, Saturn, Uranus, Neptune) which we find in our own solar system. The newly-launched TESS mission will find many more of them, with the help of ground-based spectroscopic follow-up. The next generation space telescope, the James Webb Space Telescope, will hopefully characterize the atmosphere of some of them. This is an exciting time for those interested in these remote worlds".
The mass of a very young exoplanet has been revealed for the first time using data from ESA’s star mapping spacecraft Gaia and its predecessor, the quarter-century retired Hipparcos satellite.Astronomers Ignas Snellen and Anthony Brown from Leiden University, the Netherlands, deduced the mass of the planet Beta Pictoris b from the motion of its host star over a long period of time as captured by both Gaia and Hipparcos....In the case of Beta Pictoris b, upper limits of the planet’s mass range had been arrived at before using the radial velocity method. To obtain a better estimate, the astronomers used a different method, taking advantage of Hipparcos’ and Gaia’s measurements that reveal the precise position and motion of the planet’s host star in the sky over time.
Daniel An, Krzysztof A. Meissner, Roger Penrose(Submitted on 6 Aug 2018) This paper presents powerful observational evidence of anomalous individual points in the very early universe that appear to be sources of vast amounts of energy, revealed as specific signals found in the CMB sky. Though seemingly problematic for cosmic inflation, the existence of such anomalous points is an implication of conformal cyclic cosmology (CCC), as what could be the Hawking points of the theory, these being the effects of the final Hawking evaporation of supermassive black holes in the aeon prior to ours. Although of extremely low temperature at emission, in CCC this radiation is enormously concentrated by the conformal compression of the entire future of the black hole, resulting in a single point at the crossover into our current aeon, with the emission of vast numbers of particles, whose effects we appear to be seeing as the observed anomalous points. Remarkably, the B-mode location found by BICEP 2 is at one of these anomalous points.
This article doesn’t sound terrible convinced by the paper with the use of the term eccentric and the comments underneath are pretty scathing.https://www.livescience.com/63392-black-holes-from-past-universes.html
Roger Penrose isn't a name that warrants scoffing at and ignoring in favor of anonymous internet commentators.
Penrose has been pushing his conformal cyclic cosmology for many years and this isn't the first time that he has claimed to find some features in the CMB that prove his theory. Very few people have been convinced.
Quote from: as58 on 08/22/2018 04:39 amPenrose has been pushing his conformal cyclic cosmology for many years and this isn't the first time that he has claimed to find some features in the CMB that prove his theory. Very few people have been convinced.Fair enough.