Metallic Asteroids in the IRAS Minor Planet Survey - a NEOShield Study

Studies of the compositions of asteroids, especially their metal content, are relevant not only to investigations of their nature, but also to estimations of their potential to wreak devastation on impacting the Earth. In this respect it is informative to compare the airburst of a stony object, such as the Tunguska event, which destroyed a forest but left no crater, with the impact of a similarly sized metallic object, which produced the 1.2 km diameter Barringer Crater in Arizona. In view of the evident link between metal content and the near-Earth asteroid thermal model (NEATM; Harris 1998) fitting parameter, eta, which carries information on thermal inertia (Harris and Drube, 2014; see abstract submitted to this conference), we are carrying out a re-analysis of Infrared Astronomical Satellite (IRAS) data (Tedesco et al., 2002) with NEATM to further explore the dependence of eta and thermal inertia on metal content. In addition to calculating best-fit values of eta, we are calculating the angle between the spin vector and the solar direction, theta, for all IRAS sightings of each asteroid for which a spin vector is available. The eta values of objects with high thermal inertia and moderate to high spin rates should depend strongly on theta, whereas those with low thermal inertia and/or low spin rates should not. By studying the relationships between theta and eta, we aim to further explore the potential of the results of Harris and Drube (2014) and provide insight into relationships between asteroid thermal properties, taxonomic type, albedo, spin rate, etc. We will present the first results of our work and provide a demonstration of its potential. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 282703 (NEOShield Project). Harris, A. W., 1998, Icarus, 131, 291. Harris, A. W. and Drube, L, 2014, Ap. J. Letters, 785, L4 Tedesco, E. F. et al, 2002, Astron. J., 123, 1056

The Neoshield project for Near-Earth object impact threat mitigation

Every day Earth is hit by around 100 tonnes of cosmic material, most of it comes in the form of dust or small rocks, which burn up as meteors in the atmosphere. Sometimes, however, larger objects, asteroids or comets, enter the Earth’s atmosphere and then even relatively small objects can cause considerable damage. The object that exploded over the Russian city of Chelyabinsk in February 2013 had a diameter of only 17–20 m, yet it produced a blast wave that damaged buildings and injured some 1500 people. It entered the Earth’s atmosphere with a velocity of 65 000 km/h and, due to the frictional heating and stresses caused by compression of the air, it exploded at an altitude of some 25 km releasing an energy 30 times that of the Hiroshima bomb. The potentially devastating effects on Earth of a collision with a large asteroid or comet are now well recognized by scientists and policy makers. So the question is now, can we protect our civilization from the next major impact? NEOShield, a project funded by the European Commission’ Seventh Framework Programme, brought together an international team of 13 partner organizations from 6 countries to address the global issue of near-­‐Earth object (NEO) impact prevention. The project ran from 2012 to mid 2015, after which the NEOShield-­‐2 project funded by the European Commission’ H2020 Programme is continuing the research until fall 2017. The purpose of the projects is to carry out detailed analysis of realistic options for preventing a potentially catastrophic impact of a NEO on Earth. While a mitigation test mission is beyond the financial scope of the current project, the NEOShield technical partners, with the support of the science team, aim to provide detailed designs of appropriate test-­‐missions for the 3 most feasible mitigation concepts: kinetic impactor, gravity tractor, and blast deflection, so that it will be possible to quickly develop an actual test mission at a later stage. Project partners are also carrying out research into the mitigation-­‐relevant physical properties of NEOs, including observations of near-­‐Earth asteroids, analysis of available observational data, laboratory experiments on asteroid analogue materials, and modelling and computer simulations. The aim of the scientific work is to facilitate predictions of the outcome of deflection attempts using different techniques on a variety of NEO types

Asteroid Thermal Inertia Estimates from Remote Infrared Observations: The Effects of Surface Roughness and Rotation Rate

The thermal inertia of an asteroid's surface can provide insight into regolith properties, such as the presence of a layer of fine dust, the density and thermal conductivity of a rocky surface, and, together with other observational data, mineralogy. Knowledge of the surface characteristics of asteroids is important for planetary defense initiatives and the extraction of resources ("asteroid mining"). A simple means of estimating asteroid thermal inertia has been proposed by Harris & Drube, which is suitable for application to large sets of thermal-infrared observational data, such as those obtained by infrared space telescopes. We compare results from the Harris-Drube estimator with recently published values of asteroid thermal inertia from detailed thermophysical modeling, and provide an explanation in terms of reduced surface roughness for some discrepant results. Smooth surfaces covered in fine dust may provide an explanation for the unexpectedly low values of thermal inertia derived from thermophysical modeling for some slowly rotating main-belt asteroids (MBAs). In the case of near-Earth objects (NEOs) we show that results from the estimator are in good agreement with those from thermophysical modeling, with just a few exceptions. We discuss the special cases of the NEOs (101955) Bennu, (162173) Ryugu, and (29075) 1950 DA in the context of results from our estimator. Given the data requirements and complexity of thermophysical modeling, data-analysis tools based on relatively simple concepts can play an important role in allowing "quick-look" assessment of thermal-infrared data of asteroids, especially NEOs.Comment: 24 pages, 9 figures, Accepted Manuscript, Ap

Competing through innovation: Let the customer judge!

Although customers are the final judges of innovations, their opinions on firms’ innovations are rarely listened to. In this article, we developed a novel model for examining the antecedents and consequences of perceived firm innovativeness. We argue that when customers cognitively register changes in the value creation introduced by a firm, they perceive the firm as more innovative and, consequently, more attractive than its competitors. Using two waves of data from nationally representative samples (1,293 and 1,583 responses), we developed measures for examining changes in value creation that firms introduce and customers can perceive. We tested our theory by applying structural equation modeling to data from a nationally representative sample (5,812 responses). We found that firms that introduced changes affecting value proposition, value actualization, and interaction space were perceived as more innovative and more attractive than their competitors. Surprisingly, changes in relationship experience are negatively associated with perceived innovativeness and contribute to lower relative attractiveness in the market. One explanation is that firms introduce relationship innovations to safeguard future cash flows, which customers do not necessarily see as innovative.publishedVersio

A role for human N-alpha acetyltransferase 30 (Naa30) in maintaining mitochondrial integrity

N-terminal acetylation (Nt-acetylation) by N-terminal acetyltransferases (NATs) is one of the most common protein modifications in eukaryotes. The NatC complex represents one of three major NATs of which the substrate profile remains largely unexplored. Here, we defined the in vivo human NatC Nt-acetylome on a proteome-wide scale by combining knockdown of its catalytic subunit Naa30 with positional proteomics. We identified 46 human NatC substrates, expanding our current knowledge on the substrate repertoire of NatC which now includes proteins harboring Met-Leu, Met-Ile, Met-Phe, Met-Trp, Met-Val, Met-Met, Met-His and Met-Lys N termini. Upon Naa30 depletion the expression levels of several organellar proteins were found reduced, in particular mitochondrial proteins, some of which were found to be NatC substrates. Interestingly, knockdown of Naa30 induced the loss of mitochondrial membrane potential and fragmentation of mitochondria. In conclusion, NatC N-tacetylates a large variety of proteins and is essential for mitochondrial integrity and function

Dealing with Uncertainties in Asteroid Deflection Demonstration Missions: NEOTwIST

Deflection missions to near-Earth asteroids will encounter non-negligible uncertainties in the physical and orbital parameters of the target object. In order to reliably assess future impact threat mitigation operations such uncertainties have to be quantified and incorporated into the mission design. The implementation of deflection demonstration missions offers the great opportunity to test our current understanding of deflection relevant uncertainties and their consequences, e.g., regarding kinetic impacts on asteroid surfaces. In this contribution, we discuss the role of uncertainties in the NEOTwIST asteroid deflection demonstration concept, a low-cost kinetic impactor design elaborated in the framework of the NEOShield project. The aim of NEOTwIST is to change the spin state of a known and well characterized near-Earth object, in this case the asteroid (25143) Itokawa. Fast events such as the production of the impact crater and ejecta are studied via cube-sat chasers and a flyby vehicle. Long term changes, for instance, in the asteroid's spin and orbit, can be assessed using ground based observations. We find that such a mission can indeed provide valuable constraints on mitigation relevant parameters. Furthermore, the here proposed kinetic impact scenarios can be implemented within the next two decades without threatening Earth's safety.Comment: Accepted for publication in the proceedings of the IAUS 318 - Asteroids: New Observations, New Models, held at the IAU General Assembly in Honolulu, Hawaii, USA 201

Detection of Helium in the Atmosphere of the Exo-Neptune HAT-P-11b

The helium absorption triplet at a wavelength of 10,833 \AA\ has been proposed as a way to probe the escaping atmospheres of exoplanets. Recently this feature was detected for the first time using Hubble Space Telescope (HST) WFC3 observations of the hot Jupiter WASP-107b. We use similar HST/WFC3 observations to detect helium in the atmosphere of the hot Neptune HAT-P-11b at the $4\sigma$ confidence level. We compare our observations to a grid of 1D models of hydrodynamic escape to constrain the thermospheric temperatures and mass loss rate. We find that our data are best fit by models with high mass loss rates of $\dot{M} \approx 10^{9}$ - $10^{11}$ g s$^{-1}$. Although we do not detect the planetary wind directly, our data are consistent with the prediction that HAT-P-11b is experiencing hydrodynamic atmospheric escape. Nevertheless, the mass loss rate is low enough that the planet has only lost up to a few percent of its mass over its history, leaving its bulk composition largely unaffected. This matches the expectation from population statistics, which indicate that close-in planets with radii greater than 2 R$_{\oplus}$ form and retain H/He-dominated atmospheres. We also confirm the independent detection of helium in HAT-P-11b obtained with the CARMENES instrument, making this the first exoplanet with the detection of the same signature of photoevaporation from both ground- and space-based facilities.Comment: 12 pages, 9 figures, accepted for publication in ApJ

DEN SUNDHEDSSKADELIGE BØN – Om fjernforbøn, spiritualitet og dårlig videnskab

At religion kan være sundhedsskadeligt er velkendt. Men at bøn også kan være det, er noget nyt. Herbert Benson, læge ved Harvard Universitet, har foretaget en storstilet videnskabelig undersøgelse af fjernforbøn på seks forskellige amerikanske sygehuse. Undersøgelsen viser – stik imod Bensons personlige forhåbninger – ikke alene, at fjernforbøn ingen positiv virkning har på hjertepatienter, men også at patienternes viden om, at nogen beder for dem, oven i købet kan være livsfarlig. Efter en kort introduktion til forskningen om religion og sundhed, gennemgår denne artikel tre udvalgte lægevidenskabelige forsøg. Det drejer sig om Krucoffs MANTRA-undersøgelse fra 2001 ved Veterans Administration Medical Center i USA; Leibovicis retroaktive undersøgelse fra 2001 ved Rabin Medical Center i Israel; samt Bensons ovenfor omtalte undersøgelse fra 2006. I dansk litteratur blev disse og andre undersøgelser introduceret i bogen KAN TRO FLYTTE BJERGE? (København 2004) i kapitlet »Moderne fjernforbønsunder søgelser og de spørgsmål de rejser«, som er skrevet af bogens redaktører Christoffer Johansen og Niels Christian Hvidt. Disse tre undersøgelser underkastes i denne artikel en nøgtern kritik og artiklen afsluttes med en diskussion af forsøgenes metodiske, videnskabsteoretiske, religionsvidenskabelige, videnskabsetiske og videnskabsstrategiske problemer