The Kepler mission has revealed a great diversity of planetary systems and architectures, but most of the planets discovered by Kepler orbit faint stars. Using new data from the K2 mission, we present the discovery of a five planet system transiting a bright (V = 8.9, K = 7.7) star called HIP 41378. HIP 41378 is a slightly metal-poor late F-type star with moderate rotation (v sin(i) = 7 km/s) and lies at a distance of 116 +/- 18 from Earth. We find that HIP 41378 hosts two sub-Neptune sized planets orbiting 3.5% outside a 2:1 period commensurability in 15.6 and 31.7 day orbits. In addition, we detect three planets which each transit once during the 75 days spanned by K2 observations. One planet is Neptune sized in a likely ~160 day orbit, one is sub-Saturn sized likely in a ~130 day orbit, and one is a Jupiter sized planet in a likely ~1 year orbit. We show that these estimates for the orbital periods can be made more precise by taking into account dynamical stability considerations. We also calculate the distribution of stellar reflex velocities expected for this system, and show that it provides a good target for future radial velocity observations. If a precise orbital period can be determined for the outer Jovian planet through future observations, it will be an excellent candidate for follow-up transit observations to study its atmosphere and measure its oblateness.
Exploiting the Kepler transit data, we uncover a dramatic distinction in the prevalence of sub-Jovian companions between systems that contain hot Jupiters (HJs) (periods inward of 10 days) and those that host warm Jupiters (WJs) (periods between 10 and 200 days). HJs, with the singular exception of WASP-47b, do not have any detectable inner or outer planetary companions (with periods inward of 50 days and sizes down to 2 R Earth). Restricting ourselves to inner companions, our limits reach down to 1 R Earth. In stark contrast, half of the WJs are closely flanked by small companions. Statistically, the companion fractions for hot and WJs are mutually exclusive, particularly in regard to inner companions. The high companion fraction of WJs also yields clues to their formation. The WJs that have close-by siblings should have low orbital eccentricities and low mutual inclinations. The orbital configurations of these systems are reminiscent of those of the low-mass close-in planetary systems abundantly discovered by the Kepler mission. This, and other arguments, lead us to propose that these WJs are formed in situ. There are indications that there may be a second population of WJs with different characteristics. In this picture, WASP-47b could be regarded as the extending tail of the in situ WJs into the HJ region and does not represent the generic formation route for HJs.
NASA's Kepler spacecraft continues its fruitful exoplanet hunt with the newest discovery of two super-Earth-sized alien worlds. The newly detected planets are orbiting a nearby sun-sized star known as HD 3167, located some 150 light years away. The results are presented in a paper published July 18 on the arXiv pre-print server.Although Kepler has lost two of its four reaction wheels and therefore cannot be precisely pointed toward stars, it is still capable of detecting new exoworlds. The spacecraft is now in its extended mission, known as K2, during which it has already found over 100 new planets. The HD 3167 system is just the latest addition to the vast collection of extrasolar worlds detected by K2.HD 3167 was observed by Kepler between January 3 and March 23, 2016 during Campaign 8 of its K2 mission. This observation campaign allowed a team of astronomers, led by Andrew Vanderburg of the Harvard–Smithsonian Center for Astrophysics (CfA), to detect two transit signals that could be planets circling around this nearby star."We identified two planet candidates transiting HD 3167 after processing pixel-level data to produce a light curve, removing systematic effects due to Kepler's unstable pointing, and searching for planets using a Box Least Squares periodogram search," the researchers wrote in the paper.
Kepler Mission Manager Update: K2 Campaign 10During a scheduled contact with NASA's Kepler space telescope on Thursday, July 28, the team found the photometer—the camera onboard the spacecraft—powered off. The photometer was turned on again and the flight system returned to autonomous science operations on Monday, Aug. 1. We will confirm that science operations have been resumed within a week. The team is currently investigating the cause; the spacecraft is otherwise operating normally.
While the cause of this is yet to be confirmed, the observables are in family with those seen in conjunction with the failure of science CCD Modules 3 and 7 in 2010 and 2014. Further, thermal data retrieved from the spacecraft are strongly suggestive of a drop in power dissipated by Module 4 that is again in family with a similar drop when Modules 3 and 7 failed. Thus there is a strong likelihood that Module 4 is no longer functioning. If this is indeed the case, this would leave us with 18 remaining science modules of the initial 21.
A group of researchers from the National Astronomical Observatory of Japan (NAOJ), the University of Tokyo, and the Astrobiology Center among others has observed the transit of a potentially Earth-like extrasolar planet known as K2-3d using the MuSCAT instrument on the Okayama Astrophysical Observatory 188-centimetre telescope. A transit is a phenomenon in which a planet passes in front of its parent star, blocking a small amount of light from the star, like a shadow of the planet. While transits have previously been observed for thousands of other extrasolar planets, K2-3d is important because there is a possibility that it might harbour extraterrestrial life.
K2-3d is an extrasolar planet 147 light-years away that was discovered by NASA’s Kepler K2 mission. K2-3d’s size is 1.5 times that of the Earth. The planet orbits its host star — also known as EPIC 201367065, hosting two other super-Earth exoplanets, K2-3b and c — which is half the size of the Sun, with a period of about 45 days. Compared to the Earth, the planet orbits close to its host star (about ⅕ of the Earth-Sun distance). But, because the temperature of the host star is lower than that of the Sun, calculations show that this is the right distance for the planet to have a relatively warm climate like the Earth’s. There is a possibility that liquid water could exist on the surface of the planet, raising the tantalising possibility of extraterrestrial life.K2-3d’s orbit is aligned so that as seen from Earth, it transits (passes in front of) its host star. This causes, short, periodic decreases in the star’s brightness, as the planet blocks some of the star’s light. This alignment enables researchers to probe the atmospheric composition of these planets by precise measurement of the amount of blocked starlight at different wavelengths.About 30 potentially habitable planets that also have transiting orbits were discovered by NASA’s Kepler mission, but most of these planets orbit fainter, more distant stars. Because it is closer to Earth and its host star is brighter, K2-3d is a more interesting candidate for detailed follow-up studies. The brightness decrease of the host star caused by the transit of K2-3d is small, only 0.07 percent. However, it is expected that the next generation of large telescopes will be able to measure how this brightness decrease varies with wavelength, enabling investigations of the composition of the planet’s atmosphere. If extraterrestrial life exists on K2-3d, scientists hope to be able to detect molecules related to it, such as oxygen, in the atmosphere.MuSCAT observations and transit ephemeris improvementsThe orbital period of K2-3d is about 45 days. Since the K2 mission’s survey period is only 80 days for each area of sky, researchers could only measure two transits in the K2 data. This isn’t sufficient to measure the planet’s orbital period precisely, so when researchers attempt to predict the times of future transits, creating something called a “transit ephemeris,” but there are uncertainties in the predicted times. These uncertainties grow larger as they try to predict further into the future. Therefore, early additional transit observations and adjustments to the ephemeris were required before researchers lost track of the transit. Because of the importance of K2-3d, NASA’s Spitzer Space Telescope observed two transits soon after the planet’s discovery, bringing the total to four transit measurements. However, the addition of even a single transit measurement farther in the future can help to yield a significantly improved ephemeris.Using the Okayama 188-centimetre Reflector Telescope and the latest observational instrument MuSCAT, the team observed a transit of K2-3d for the first time with a ground-based telescope. Though a 0.07 percent brightness decrease is near the limit of what can be observed with ground-based telescopes, MuSCAT’s ability to observe three wavelength bands simultaneously enhanced its ability to detect the transit. By reanalysing the data from K2 and Spitzer in combination with this new observation, researchers have greatly improved the precision of the ephemeris, determining the orbital period of the planet to within about 18 seconds (1/30 of the original uncertainty). This improved transit ephemeris ensures that when the next generation of large telescopes come online, they will know exactly when to watch for transits. Thus these research results help pave the way for future extraterrestrial life surveys.
I like this sensational piece regarding Thursday's NASA press conference...https://www.express.co.uk/news/science/890401/aliens-nasa-breakthrough-exoplanets-space-planet-solar-system-ai-ufo