Rotation periods and colours of 10-m scale near-Earth asteroids from CFHT target of opportunity streak photometry

The rotational properties of $\sim$10~m-scale asteroids are poorly understood with only a few measurements. Additionally, collisions or thermal recoil can spin their rotations to periods less than a few seconds obfuscating their study due to the observational cadence imposed by the long read-out times of charge-coupled device imagers. We present a method to measure the rotation periods of 10~m-scale asteroids using the target of opportunity capability of the Canada France Hawaii Telescope and its MegaCam imager by intentionally streaking their detections in single exposures when they are at their brightest. Periodic changes in brightness as small as $\sim$0.05 mag along the streak can be measured as short as a few seconds. Additionally, the streak photometry is taken in multiple g, r, and i filter exposures enabling the measurement of asteroid colours. The streak photometry method was tested on CFHT observations of three 10~m-scale asteroids, 2016 GE$_1$, 2016 CG$_{18}$, and 2016 EV$_{84}$. Our 3 targets are among the smallest known asteroids with measured rotation periods/colours having some of the shortest known rotation periods. We compare our rotation period and taxonomic results with independent data from the literature and discuss applications of the method to future small asteroid observations.Comment: Revised version, MNRAS:L, 13 pages, 10 figures, 3 table

MPEC 2020-A99: 2020 AV2

[no abstract

Keck and Gemini spectral characterization of Lucy mission fly-by target (152830) Dinkinesh

Recently, the inner main belt asteroid (152830) Dinkinesh was identified as an additional fly-by target for the Lucy mission. The heliocentric orbit and approximate absolute magnitude of Dinkinesh are known, but little additional information was available prior to its selection as a target. In particular, the lack of color spectrophotometry or spectra made it impossible to assign a spectral type to Dinkinesh from which its albedo could be estimated. We set out to remedy this knowledge gap by obtaining visible wavelength spectra with the Keck telescope on 2022 November 23 and with Gemini-South on 2022 December 27. The spectra measured with the Keck I/Low Resolution Imaging Spectrometer (LRIS) and the Gemini South/Gemini Multi-Object Spectrograph South (GMOS-S) are most similar to the average spectrum of S- and Sq-type asteroids. The most diagnostic feature is the $\approx$15$\pm$1$\%$ silicate absorption feature at $\approx$0.9-1.0~micron. Small S- and Sq-type asteroids have moderately high albedos ranging from 0.17-0.35. Using this albedo range for Dinkinesh in combination with measured absolute magnitude, it is possible to derive an effective diameter and surface brightness for this body. The albedo, size and surface brightness are important inputs required for planning a successful encounter by the Lucy spacecraft.Comment: 7 pages, 1 figure. Under review in Icaru

`Oumuamua as a messenger from the Local Association

7 pages, one table, two figures, accepted for publication by ApJL. © 2018. The American Astronomical Society. All rights reserved.With a hyperbolic trajectory around the Sun, 'Oumuamua is the first confirmed interstellar object. However, its origin is poorly known. By simulating the orbits of 0.23 million local stars, we find 109 encounters with periastron less than 5 pc. 'Oumuamua's low peculiar velocity is suggestive of its origin from a young stellar association with similar velocity. In particular, we find that 'Oumuamua would have had slow encounters with at least five young stars belonging to the Local Association, thus suggesting these as plausible sites for formation and ejection. In addition to an extremely elongated shape, the available observational data for 'Oumuamua indicates a red color, suggestive of a potentially organic-rich and activity-free surface. These characteristics seem consistent with formation through energetic collisions between planets and debris objects in the middle part of a young stellar system. We estimate an abundance of at least 6.0 × 10 -3 au -3 for such interstellar objects with mean diameter larger than 100 m and find that it is likely that most of them will be ejected into the Galactic halo. Our Bayesian analysis of the available light curves indicates a rotation period of 6.96 +1.45 -0.39, which is consistent with the estimation by Meech et al. and shorter than those in other literature. The codes and results are available on GitHub (https://github.com/phillippro/Oumuamua).Peer reviewe

A Human Development Framework for CO2 Reductions

Although developing countries are called to participate in CO2 emission reduction efforts to avoid dangerous climate change, the implications of proposed reduction schemes in human development standards of developing countries remain a matter of debate. We show the existence of a positive and time-dependent correlation between the Human Development Index (HDI) and per capita CO2 emissions from fossil fuel combustion. Employing this empirical relation, extrapolating the HDI, and using three population scenarios, the cumulative CO2 emissions necessary for developing countries to achieve particular HDI thresholds are assessed following a Development As Usual approach (DAU). If current demographic and development trends are maintained, we estimate that by 2050 around 85% of the world's population will live in countries with high HDI (above 0.8). In particular, 300Gt of cumulative CO2 emissions between 2000 and 2050 are estimated to be necessary for the development of 104 developing countries in the year 2000. This value represents between 20% to 30% of previously calculated CO2 budgets limiting global warming to 2{\deg}C. These constraints and results are incorporated into a CO2 reduction framework involving four domains of climate action for individual countries. The framework reserves a fair emission path for developing countries to proceed with their development by indexing country-dependent reduction rates proportional to the HDI in order to preserve the 2{\deg}C target after a particular development threshold is reached. Under this approach, global cumulative emissions by 2050 are estimated to range from 850 up to 1100Gt of CO2. These values are within the uncertainty range of emissions to limit global temperatures to 2{\deg}C.Comment: 14 pages, 7 figures, 1 tabl

Palomar discovery and initial characterization of naked-eye long period comet C/2022 E3 (ZTF)

Long-period comets are planetesimal remnants constraining the environment and volatiles of the protoplanetary disc. We report the discovery of hyperbolic long-period comet C/2022 E3 (ZTF), which has a perihelion $\sim$1.11 au, an eccentricity $\gtrsim$1 and an inclination $\sim$109$^{\circ}$, from images taken with the Palomar 48-inch telescope during morning twilight on 2022 Mar 2. Additionally, we report the characterization of C/2022 E3 (ZTF) from observations taken with the Palomar 200-inch, the Palomar 60-inch, and the NASA Infrared Telescope Facility in early 2023 February to 2023 March when the comet passed within $\sim$0.28 au of the Earth and reached a visible magnitude of $\sim$5. We measure g-r = 0.70$\pm$0.01, r-i = 0.20$\pm$0.01, i-z = 0.06$\pm$0.01, z-J = 0.90$\pm$0.01, J-H = 0.38$\pm$0.01 and H-K = 0.15$\pm$0.01 colours for the comet from observations. We measure the A(0$^\circ$)f$\rho$ (0.8~$\mu$m) in a 6500~km radius from the nucleus of 1483$\pm$40~cm, and CN, C$_3$, and C$_2$ production of 5.43$\pm0.11\times$10$^{25}$~mol/s, 2.01$\pm0.04\times$10$^{24}$, and 3.08$\pm0.5\times$10$^{25}$~mol/s, similar to other long period comets. We additionally observe the appearance of jet-like structures at a scale of $\sim$4,000 km in wide-field g-band images, which may be caused by the presence of CN gas in the near-nucleus coma.Comment: Accepted for publication in MNRAS:L, 9 pages, 6 figures, 2 table

An interdisciplinary system dynamics model for post-disaster housing recovery

Many previous disasters have demonstrated the need for extensive personal, public, and governmental expenditures for housing recovery highlighting the importance of studying housing recovery. Yet, much research is still needed to fully understand the multi-faceted and complex nature of housing recovery. The goal of this paper is to present a holistic model to further the understanding of the dynamic processes and interdependencies of housing recovery. The impetus for this work is that inequalities in housing recovery could be addressed more effectively if we better understood interconnected factors and dynamic processes that slow down recovery for some. Currently, there is a lack of understanding about such factors and processes. Literature from engineering and social sciences was reviewed to develop an integrated system dynamics model for post-disaster housing recovery. While it is beyond current capabilities to quantify such complexities, the presented model takes a major stride toward articulating the complex phenomenon that is housing recovery

The Contribution of Social Networks to the Health and Self-Management of Patients with Long-Term Conditions: A Longitudinal Study

Evidence for the effectiveness of patient education programmes in changing individual self-management behaviour is equivocal. More distal elements of personal social relationships and the availability of social capital at the community level may be key to the mobilisation of resources needed for long-term condition self-management to be effective. Aim: To determine how the social networks of people with long-term conditions (diabetes and heart disease) are associated with health-related outcomes and changes in outcomes over time. Methods: Patients with chronic heart disease (CHD) or diabetes (n = 300) randomly selected from the disease registers of 19 GP practices in the North West of England. Data on personal social networks collected using a postal questionnaire, alongside face-to-face interviewing. Follow-up at 12 months via postal questionnaire using a self-report grid for network members identified at baseline. Analysis: Multiple regression analysis of relationships between health status, self-management and health economics outcomes, and characteristics of patients’ social networks. Results: Findings indicated that: (1) social involvement with a wider variety of people and groups supports personal self-management and physical and mental well-being; (2) support work undertaken by personal networks expands in accordance with health needs helping people to cope with their condition; (3) network support substitutes for formal care and can produce substantial saving in traditional health service utilisation costs. Health service costs were significantly (p0.01) reduced for patients receiving greater levels of illness work through their networks. Conclusions: Support for self-management which achieves desirable policy outcomes should be construed less as an individualised set of actions and behaviour and more as a social network phenomenon. This study shows the need for a greater focus on harnessing and sustaining the capacity of networks and the importance of social involvement with community groups and resources for producing a more desirable and cost-effective way of supporting long term illness management