No abstract

We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq = 525 ± 11 K) with a radius of Rb = 1.217 ± 0.084 R⊕ and an orbital period of Pb = 3.93 d. Precise stellar radial velocities from CARMENES and PFS, as well as archival data from HIRES, UVES, and HARPS also display a 3.93-day periodicity, confirming the planetary nature and leading to a planetary mass of Mb = 1.84 ± 0.31 M⊕. In addition to the radial velocity signal for GJ 357 b, more periodicities are present in the data indicating the presence of two further planets in the system: GJ 357 c, with a minimum mass of Mc = 3.40 ± 0.46 M⊕ in a 9.12 d orbit, and GJ 357 d, with a minimum mass of Md = 6.1 ± 1.0 M⊕ in a 55.7 d orbit inside the habitable zone. The host is relatively inactive and exhibits a photometric rotation period of Prot = 78 ± 2 d. GJ 357 b isto date the second closest transiting planet to the Sun, making it a prime target for further investigations such as transmission spectroscopy. Therefore, GJ 357 b represents one of the best terrestrial planets suitable for atmospheric characterization with the upcoming JWST and ground-based ELTs.

We present the discovery of eight new radio pulsars located in the Large Magellanic Cloud (LMC). Five of these pulsars were found from reprocessing the Parkes Multibeam Survey of the Magellanic Clouds, while the remaining three were from an ongoing new survey at Parkes with a high resolution data acquisition system. It is possible that these pulsars were missed in the earlier processing due to radio frequency interference, visual judgment, or the large number of candidates that must be analysed. One of these new pulsars has a dispersion measure of 273 pc cm −3 , almost twice the highest previously known value, making it possibly the most distant LMC pulsar. In addition, we present the null result of a radio pulse search of an X-ray point source located in SNR J0047.2−7308 in the Small Magellanic Cloud (SMC). Although no millisecond pulsars have been found, these discoveries have increased the known rotation powered pulsar population in the LMC by more than 50%. Using the current sample of LMC pulsars, we used a Bayesian analysis to constrain the number of potentially observable pulsars in the LMC to within a 95% credible interval of 57000 +70000 −30000 . The new survey at Parkes is ∼20% complete and it is expected to yield at most six millisecond pulsars in the LMC and SMC. Although it is very sensitive to short period pulsars, this new survey provides only a marginal increase in sensitivity to long periods. The limiting luminosity for this survey is 125 mJy kpc 2 for the LMC which covers the upper 10% of all known radio pulsars. The luminosity function for normal pulsars in the LMC is consistent with their counterparts in the Galactic disk. The maximum 1400 MHz radio luminosity for LMC pulsars is ∼ 1000 mJy kpc 2 .

Immersive virtual reality (VR) has enormous potential for education, but classroom resources are limited. Thus, it is important to identify whether and when VR provides sufficient advantages over other modes of learning to justify its deployment. In a between-subjects experiment, we compared three methods of teaching Moon phases (a hands-on activity, VR, and a desktop simulation) and measured student improvement on existing learning and attitudinal measures. While a substantial majority of students preferred the VR experience, we found no significant differences in learning between conditions. However, we found differences between conditions based on gender, which was highly correlated with experience with video games. These differences may indicate certain groups have an advantage in the VR setting. are many potential explanations for these differences [14], two relate to how learners and technology interact through issues of embodiment and real-world complexities. This study aimed to test the impact of these variables by directly comparing student learning and attitudes from three different instructional technologies (a hands-on activity, desktop simulation, and virtual reality simulation), while taking advantage of their respective affordances along the dimensions of embodiment and real-world complexity. EmbodimentTheories of learning argue that cognition is inherently embodied: "the mind must be understood in the context of its relationship to a physical body that interacts with the world." [15, p.625]. Research has found that learning benefits from activities that explicitly attend to embodied cognition [16][17][18]. There are several ways in which embodiment is argued to support learning, generally tied to a hypothesis whereby activities help move cognition from abstract to concrete representations of a phenomenon [16].Two such notions of embodied cognition focus on how learners off-load cognitive work on to the environment and how off-line cognition is body-based [15,19]. These notions suggest physical aspects of cognition, whereby learning is supported through engaging perceptuo-motor systems [20]. Indeed, nearly all science education advocates for the use of interactive hands-on activities [21]. Through hands-on activities and demonstrations, learners connect abstract concepts to their physical environment. For example, researchers in physics education have developed embodied activities for teaching concepts of energy conservation [22]. In these activities, learners assign units of energy to physical objects (either cubes or people) [23], and then manipulate those objects to represent processes of energy transfer and dynamics. Through these concrete representations of an otherwise abstract phenomenon, learners develop their conceptual and mechanistic understandings of the phenomenon [22]. By manipulating physical objects, students can see deep features of the phenomena, allowing them to effectively integrate the features into their mental models of the phenomena [20,24].Two other notions of embodied cogn...

We present a catalog of spectra and geometric albedos, representative of the different types of solar system bodies, from 0.45 to 2.5 μm. We analyzed published calibrated, uncalibrated spectra, and albedos for solar system objects and derived a set of reference spectra and reference albedos for 19 objects that are representative of the diversity of bodies in our solar system. We also identified previously published data that appear contaminated. Our catalog provides a baseline for comparison of exoplanet observations to 19 bodies in our own solar system, which can assist in the prioritization of exoplanets for time intensive follow-up with next-generation extremely large telescopes and space-based direct observation missions. Using high- and low-resolution spectra of these solar system objects, we also derive colors for these bodies and explore how a color-color diagram could be used to initially distinguish between rocky, icy, and gaseous exoplanets. We explore how the colors of solar system analog bodies would change when orbiting different host stars. This catalog of solar system reference spectra and albedos is available for download through the Carl Sagan Institute.