200 research outputs found
NEOExchange -- An online portal for NEO and Solar System science
Las Cumbres Observatory (LCO) has deployed a network of ten identical 1-m
telescopes to four locations. The global coverage and flexibility of the LCO
network makes it ideal for discovery, follow-up, and characterization of all
Solar System objects, and especially Near-Earth Objects (NEOs). We describe the
"LCO NEO Follow-up Network" which makes use of the LCO network of robotic
telescopes and an online, cloud-based web portal, NEOexchange, to perform
photometric characterization and spectroscopic classification of NEOs and
follow-up astrometry for both confirmed NEOs and unconfirmed NEO candidates.
The follow-up astrometric, photometric, and spectroscopic characterization
efforts are focused on those NEO targets that are due to be observed by the
planetary radar facilities and those on the NHATS lists. Astrometry allows us
to improve target orbits, making radar observations possible for objects with a
short arc or large orbital uncertainty and also allows for the detection and
measurement of the Yarkovsky effect on NEOs. Photometric & spectroscopic data
allows us to determine the light curve shape and amplitude, measure rotation
periods, determine the taxonomic classification, and improve the overall
characterization of these targets. We describe the NEOexchange follow-up portal
and the methodology adopted which allows the software to be packaged and
deployed anywhere, including in off-site cloud services. This allows
professionals, amateurs, and citizen scientists to plan, schedule and analyze
NEO imaging and spectroscopy data using the LCO network and acts as a
coordination hub for the NEO follow-up efforts. We illustrate these
capabilities with examples of first period determinations for radar-targeted
NEOs and its use to plan and execute multi-site photometric and spectroscopic
observations of (66391) 1999 KW4, the subject of the most recent planetary
defense exercise campaign.Comment: 35 pages, 6 figures, accepted by Icarus. Available on the web at
https://lco.global/neoexchange/ code available from GitHub at
https://github.com/LCOGT/neoexchange
Managing fisheries to conserve North Sea groundfish and benthic invertebrate species diversity
Concerns over man’s impact on the environment and ecosystems of the world have resulted in a shift in emphasis in the management of marine natural resources. Consequently, an ecosystem approach to management (EAM) is in the process of being developed and implemented for the North Se
Splitting of Long-Period Comet C/2018 F4 (PANSTARRS)
Long-period comet C/2018 F4 (PANSTARRS) was observed to show duplicity of its
inner region in 2020 September, suggestive of a splitting event. We here
present analyses of our observations of the comet taken from the LOOK project
and the University of Hawaii 2.2 m telescope after the discovery of the
splitting. The two fragments Components A and B, estimated to be m
to 4 km in radius, remained highly similar to each other in terms of
brightness, colour, and dust morphology throughout our observing campaign from
2020 September to 2021 December. Our fragmentation model yielded that the two
components split at a relative speed of m s in 2020 late
April, implying a specific energy change of J kg, and that Component B was subjected to a stronger
nongravitational acceleration than Component A in both the radial and normal
directions of the orbit. The obtained splitting time is broadly consistent with
the result from the dust morphology analysis, which further suggested that the
dominant dust grains were millimeter-sized and ejected at speed m
s. We postulate that the pre-split nucleus of the comet consisted of two
lobes resembling the one of 67P, or that the comet used to be a binary system
like main-belt comet 288P. Regardless, we highlight the possibility of using
observations of split comets as a feasible manner to study the bilobate shape
or binarity fraction of cometary nuclei.Comment: Accepted to AJ for publicatio
Easily retrievable objects among the NEO population
Asteroids and comets are of strategic importance for science in an effort to understand the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this paper, we consider the currently known NEO population and define a family of so-called Easily Retrievable Objects (EROs), objects that can be transported from accessible heliocentric orbits into the Earth’s neighbourhood at affordable costs. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun-Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy Earth transfers for asteroid material. A catalogue of asteroid retrieval candidates is then presented. Despite the highly incomplete census of very small asteroids, the ERO catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of Δv. Moreover, the approach proposed represents a robust search and ranking methodology for future retrieval candidates that can be automatically applied to the growing survey of NEOs
Distribution and abundance of cephalopods in UK waters: long-term trends and environmental relationships
As part of a project which aimed to evaluate the feasibility of developing indicators of marine ecosystem status based on cephalopods, we analysed spatiotemporal variation in abundance,, and environmental relationships, using trawl survey catch data for cephalopods in UK waters (1980-2013) from Cefas and Marine Scotland Science databases. These data presented some challenges, notably the use of several different trawl gears, variable tow durations, and varying levels of taxonomic resolution. Accounting for gear type and tow duration, data were analysed separately for each cephalopod family and season to account for different phases of the life cycles being present at different times of year. The families investigated were Loliginidae, Octopodidae, Ommastrephidade, Sepiidae and Sepiolidae.
A GAM framework was used to summarise spatiotemporal variation in abundance at family level and the relationships of spatial and long-term temporal variation with environmental variables, including depth, substrate (available for inshore waters) and several oceanographic variables (e.g., SST, chl signals), also considering fishing pressure. Long-term trends for each family varied between areas and seasons, although this may reflect the presence of several species within families. In Scotland, where Loligo vulgaris is rare and L. forbesii is normally distinguished from Alloteuthis spp., survey data suggested a peak in abundance of this species around 1990 and a generally increasing trend since the mid-1990s. Spatial patterns in distribution in all families were related to both physiographic and oceanographic features. As expected substrate type had most effect on those families in which eggs are attached to objects on the seabed
Year 1 of the Legacy Survey of Space and Time (LSST): Recommendations for Template Production to Enable Solar System Small Body Transient and Time Domain Science
The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will discover ~6 million solar system planetesimals, providing in total over a billion photometric and astrometric measurements in 6 broad-band filters. Rubin Observatory's automated data reduction pipelines will employ difference imaging; templates representing the static sky will be subtracted from the nightly LSST observations in order to identify transient sources, including solar system moving objects. These templates are expected to be generated by coadding high quality images of the same pointing from the previous year's survey observations. The first year of LSST operations will require a different method for generating templates, if solar system discoveries are to be reported daily like Year 2 and beyond. We make recommendations for template production in the LSST's first year and present the opportunities for solar system small body transient and time domain science enhanced by this change
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