24 research outputs found
Near-infrared colors of minor planets recovered from VISTA - VHS survey (MOVIS)
The Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer
(WISE) provide information about the surface composition of about 100,000 minor
planets. The resulting visible colors and albedos enabled us to group them in
several major classes, which are a simplified view of the diversity shown by
the few existing spectra. We performed a serendipitous search in VISTA-VHS
observations using a pipeline developed to retrieve and process the data that
corresponds to solar system objects (SSo). The colors and the magnitudes of the
minor planets observed by the VISTA survey are compiled into three catalogs
that are available online: the detections catalog (MOVIS-D), the magnitudes
catalog (MOVIS-M), and the colors catalog (MOVIS-C). They were built using the
third data release of the survey (VISTA VHS-DR3). A total of 39,947 objects
were detected, including 52 NEAs, 325 Mars Crossers, 515 Hungaria asteroids,
38,428 main-belt asteroids, 146 Cybele asteroids, 147 Hilda asteroids, 270
Trojans, 13 comets, 12 Kuiper Belt objects and Neptune with its four
satellites. The colors found for asteroids with known spectral properties
reveal well-defined patterns corresponding to different mineralogies. The
distributions of MOVIS-C data in color-color plots shows clusters identified
with different taxonomic types. All the diagrams that use (Y-J) color separate
the spectral classes more effectively than the (J-H) and (H-Ks) plots used
until now: even for large color errors (<0.1), the plots (Y-J) vs (Y-Ks) and
(Y-J) vs (J-Ks) provide the separation between S-complex and C-complex. The end
members A, D, R, and V-types occupy well-defined regions.Comment: 19 pages, 16 figure
Expected spectral characteristics of (101955) Bennu and (162173) Ryugu, targets of the OSIRIS-REx and Hayabusa2 missions
NASA's OSIRIS-REx and JAXA's Hayabusa2 sample-return missions are currently
on their way to encounter primitive near-Earth asteroids (101955) Bennu and
(162173) Ryugu, respectively. Spectral and dynamical evidence indicates that
these near-Earth asteroids originated in the inner part of the main belt. There
are several primitive collisional families in this region, and both these
asteroids are most likely to have originated in the Polana-Eulalia family
complex. We present the expected spectral characteristics of both targets based
on our studies of our primitive collisional families in the inner belt:
Polana-Eulalia, Erigone, Sulamitis, and Clarissa. Observations were obtained in
the framework of our PRIMitive Asteroids Spectroscopic Survey (PRIMASS). Our
results are especially relevant to the planning and interpretation of in-situ
images and spectra to be obtained by the two spacecraft during the encounters
with their targets.Comment: 22 pages, 11 figures. Accepted for publication in Icarus on May 11,
201
The visible and near-infrared spectra of asteroids in cometary orbits
We study the visible and near-infrared (NIR) spectral properties of different
ACO populations and compare them to the independently determined properties of
comets.
We select our ACOs sample based on published dynamical criteria and present
our own observational results obtained using the 10.4m Gran Telescopio Canarias
(GTC), the 4.2m William Herschel Telescope (WHT), the 3.56m Telescopio
Nazionale Galileo (TNG), and the 2.5m Isaac Newton Telescope (INT), all located
at the El Roque de los Muchachos Observatory (La Palma, Spain), and the 3.0m
NASA Infrared Telescope Facility (IRTF), located at the Mauna Kea Observatory,
in Hawaii. We include in the analysis the spectra of ACOs obtained from the
literature. We derive the spectral class and the visible and NIR spectral
slopes. We also study the presence of hydrated minerals by studying the 0.7
m band and the UV-drop below 0.5 m associated with phyllosilicates.
We present new observations of 17 ACOs, 11 of them observed in the visible, 2
in the NIR and 4 in the visible and NIR. We also discuss the spectra of 12 ACOs
obtained from the literature.
All but two ACOs have a primitive-like class spectrum (X or D-type). Almost
100\% of the ACOs in long-period cometary orbits (Damocloids) are D-types.
Those in Jupiter family comet orbits (JFC-ACOs) are 60\% D-types and
40\% X-types. The mean spectral slope of JFC-ACOs is 9.7 4.6
\%/1000 \AA \ and for the Damocloids this is 12.2 2.0 \%/1000 \AA . No
evidence of hydration on the surface of ACOs is found from their visible
spectra. The slope and spectral class distribution of ACOs is similar to that
of comets.
The spectral classification, the spectral slope distribution of ACOs, and the
lack of spectral features indicative of the presence of hydrated minerals on
their surface, strongly suggest that ACOs are likely dormant or extinct comets.Comment: 11 pages, 10 Figures, published in A&
Observations of two super fast rotator NEAs: 2021 NY and 2022 AB
In the framework of the Visible NEAs Observations Survey (ViNOS) that uses
several telescopes at the Canary Islands observatories since 2018, we observed
two super fast rotator NEAs, 2021 NY and 2022 AB. We obtained photometry
and spectrophotometry of both targets and visible spectroscopy of 2022 AB.
Light curves of 2021 NY obtained in 4 different nights between Sept. 30 and
Oct. 16, 2021 return a rotation period minutes and a light
curve amplitude mag. We found that 2021 NY is a very elongated
super fast rotator with an axis ratio . We also report colours
, , and mag. These are compatible with an S-type asteroid. The light curves of
2022 AB obtained on Jan. 5 and Jan. 8, 2021 show a rotation period
minutes, with amplitudes and mag. 2022
AB is also an elongated object with axis ratio . The obtained
colours are , , and . These colours are similar to those of the X-types, but with
an unusually high value. Spectra obtained on Jan. 12 and Jan. 14, 2022,
are consistent with the reported colours. The spectral upturn over the 0.4 -
0.6 region of 2022 AB does not fit with any known asteroid taxonomical
class or meteorite spectrum, confirming its unusual surface properties.Comment: 9 pages, 7 figure
Taxonomic classification of asteroids based on MOVIS near-infrared colors
We aim to provide a taxonomic classification for asteroids observed by
VISTA-VHS survey. We derive a method for assigning a compositional type to an
object based on its (Y-J), (J-Ks), and (H-Ks) colors. We present a taxonomic
classification for 18\,265 asteroids from the MOVIS catalog, using a
probabilistic method and the k-nearest neighbors algorithm. Because our
taxonomy is based only on NIR colors, several classes from Bus-DeMeo were
clustered into groups and a slightly different notation was used (i.e. the
superscript indicates that the classification was obtained based on the NIR
colors and the subscript indicates possible miss-identifications with other
types). Our results are compared with the information provided by the Sloan
Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE). The
two algorithms used in this study give a taxonomic type for all objects having
at least (Y-J) and (J-Ks) observed colors. A final classification is reported
for a set of 6\,496 asteroids based on the criteria that KNN and probabilistic
algorithms gave the same result, (Y-J) 0.118 and
(J-Ks)0.136. This set includes 144 bodies classified as ,
613 as , 197 as , 91 as , 440 as , 665
as , 233 as , 3\,315 as , and 798 as . We
report the albedo distribution for each taxonomic group and we compute new
median values for the main types. We found that V-type and A-type candidates
have identical size frequency distributions, but the V-types are five times
more common than the A-types. Several particular cases, such as the A-type
asteroid (11616) 1996 BQ2 and the S-type (3675) Kematsch, both in the Cybele
population, are discussed. Files and codes available at:
https://github.com/marcelpopescu/MOVIS-TaxonomyComment: 18 pages, 10 figures, accepted for publication in Astronomy &
Astrophysics (A&A
Near-Earth asteroids spectroscopic survey at Isaac Newton Telescope
The population of near-Earth asteroids (NEAs) shows a large variety of
objects in terms of physical and dynamical properties. They are subject to
planetary encounters and to strong solar wind and radiation effects. Their
study is also motivated by practical reasons regarding space exploration and
long-term probability of impact with the Earth. We aim to spectrally
characterize a significant sample of NEAs with sizes in the range of 0.25
- 5.5 km (categorized as large), and search for connections between their
spectral types and the orbital parameters. Optical spectra of NEAs were
obtained using the Isaac Newton Telescope (INT) equipped with the IDS
spectrograph. These observations are analyzed using taxonomic classification
and by comparison with laboratory spectra of meteorites. A total number of 76
NEAs were observed. We classified 44 of them as Q/S-complex, 16 as B/C-complex,
eight as V-types, and another eight belong to the remaining taxonomic classes.
Our sample contains 27 asteroids categorized as potentially hazardous and 31
possible targets for space missions including (459872) 2014 EK24, (436724) 2011
UW158, and (67367) 2000 LY27. The spectral data corresponding to (276049) 2002
CE26 and (385186) 1994 AW1 shows the 0.7 m feature which indicates the
presence of hydrated minerals on their surface. We report that Q-types have the
lowest perihelia (a median value and absolute deviation of AU)
and are systematically larger than the S-type asteroids observed in our sample.
We explain these observational evidences by thermal fatigue fragmentation as
the main process for the rejuvenation of NEA surfaces. In general terms, the
taxonomic distribution of our sample is similar to the previous studies and
matches the broad groups of the inner main belt asteroids. Nevertheless, we
found a wide diversity of spectra compared to the standard taxonomic types.Comment: Accepted in Astronomy & Astrophysics (A&A
J-PLUS: The javalambre photometric local universe survey
ABSTRACT: TheJavalambrePhotometric Local UniverseSurvey (J-PLUS )isanongoing 12-band photometricopticalsurvey, observingthousands of squaredegrees of theNorthernHemispherefromthededicated JAST/T80 telescope at the Observatorio Astrofísico de Javalambre (OAJ). The T80Cam is a camera with a field of view of 2 deg2 mountedon a telescopewith a diameter of 83 cm, and isequippedwith a uniquesystem of filtersspanningtheentireopticalrange (3500–10 000 Å). Thisfiltersystemis a combination of broad-, medium-, and narrow-band filters, optimallydesigned to extracttherest-framespectralfeatures (the 3700–4000 Å Balmer break region, Hδ, Ca H+K, the G band, and the Mg b and Ca triplets) that are key to characterizingstellartypes and delivering a low-resolutionphotospectrumforeach pixel of theobservedsky. With a typicaldepth of AB ∼21.25 mag per band, thisfilter set thusallowsforanunbiased and accuratecharacterization of thestellarpopulation in our Galaxy, itprovidesanunprecedented 2D photospectralinformationforall resolved galaxies in the local Universe, as well as accuratephoto-z estimates (at the δ z/(1 + z)∼0.005–0.03 precisionlevel) formoderatelybright (up to r ∼ 20 mag) extragalacticsources. Whilesomenarrow-band filters are designedforthestudy of particular emissionfeatures ([O II]/λ3727, Hα/λ6563) up to z < 0.017, theyalsoprovidewell-definedwindowsfortheanalysis of otheremissionlines at higherredshifts. As a result, J-PLUS has thepotential to contribute to a widerange of fields in Astrophysics, both in thenearbyUniverse (MilkyWaystructure, globular clusters, 2D IFU-likestudies, stellarpopulations of nearby and moderate-redshiftgalaxies, clusters of galaxies) and at highredshifts (emission-line galaxies at z ≈ 0.77, 2.2, and 4.4, quasi-stellarobjects, etc.). Withthispaper, wereleasethefirst∼1000 deg2 of J-PLUS data, containingabout 4.3 millionstars and 3.0 milliongalaxies at r < 21mag. With a goal of 8500 deg2 forthe total J-PLUS footprint, thesenumbers are expected to rise to about 35 millionstars and 24 milliongalaxiesbytheend of thesurvey.Funding for the J-PLUS Project has been provided by the Governments of Spain and Aragón through the Fondo de Inversiones de Teruel, the Spanish Ministry of Economy and Competitiveness (MINECO; under grants AYA2017-86274-P, AYA2016-77846-P, AYA2016-77237-C3-1-P, AYA2015-66211-C2-1-P, AYA2015-66211-C2-2, AYA2012-30789, AGAUR grant SGR-661/2017, and ICTS-2009-14), and European FEDER funding (FCDD10-4E-867, FCDD13-4E-2685
Effectiveness of an mHealth intervention combining a smartphone app and smart band on body composition in an overweight and obese population: Randomized controlled trial (EVIDENT 3 study)
Background: Mobile health (mHealth) is currently among the supporting elements that may contribute to an improvement in health markers by helping people adopt healthier lifestyles. mHealth interventions have been widely reported to achieve greater weight loss than other approaches, but their effect on body composition remains unclear.
Objective: This study aimed to assess the short-term (3 months) effectiveness of a mobile app and a smart band for losing weight and changing body composition in sedentary Spanish adults who are overweight or obese.
Methods: A randomized controlled, multicenter clinical trial was conducted involving the participation of 440 subjects from primary care centers, with 231 subjects in the intervention group (IG; counselling with smartphone app and smart band) and 209 in the control group (CG; counselling only). Both groups were counselled about healthy diet and physical activity. For the 3-month intervention period, the IG was trained to use a smartphone app that involved self-monitoring and tailored feedback, as well as a smart band that recorded daily physical activity (Mi Band 2, Xiaomi). Body composition was measured using the InBody 230 bioimpedance device (InBody Co., Ltd), and physical activity was measured using the International Physical Activity Questionnaire.
Results: The mHealth intervention produced a greater loss of body weight (–1.97 kg, 95% CI –2.39 to –1.54) relative to standard counselling at 3 months (–1.13 kg, 95% CI –1.56 to –0.69). Comparing groups, the IG achieved a weight loss of 0.84 kg more than the CG at 3 months. The IG showed a decrease in body fat mass (BFM; –1.84 kg, 95% CI –2.48 to –1.20), percentage of body fat (PBF; –1.22%, 95% CI –1.82% to 0.62%), and BMI (–0.77 kg/m2, 95% CI –0.96 to 0.57). No significant changes were observed in any of these parameters in men; among women, there was a significant decrease in BMI in the IG compared with the CG. When subjects were grouped according to baseline BMI, the overweight group experienced a change in BFM of –1.18 kg (95% CI –2.30 to –0.06) and BMI of –0.47 kg/m2 (95% CI –0.80 to –0.13), whereas the obese group only experienced a change in BMI of –0.53 kg/m2 (95% CI –0.86 to –0.19). When the data were analyzed according to physical activity, the moderate-vigorous physical activity group showed significant changes in BFM of –1.03 kg (95% CI –1.74 to –0.33), PBF of –0.76% (95% CI –1.32% to –0.20%), and BMI of –0.5 kg/m2 (95% CI –0.83 to –0.19).
Conclusions: The results from this multicenter, randomized controlled clinical trial study show that compared with standard counselling alone, adding a self-reported app and a smart band obtained beneficial results in terms of weight loss and a reduction in BFM and PBF in female subjects with a BMI less than 30 kg/m2 and a moderate-vigorous physical activity level. Nevertheless, further studies are needed to ensure that this profile benefits more than others from this intervention and to investigate modifications of this intervention to achieve a global effect
Apophis Planetary Defense Campaign
We describe results of a planetary defense exercise conducted during the close approach to Earth by the near-Earth asteroid (99942) Apophis during 2020 December–2021 March. The planetary defense community has been conducting observational campaigns since 2017 to test the operational readiness of the global planetary defense capabilities. These community-led global exercises were carried out with the support of NASA’s Planetary Defense Coordination Office and the International Asteroid Warning Network. The Apophis campaign is the third in our series of planetary defense exercises. The goal of this campaign was to recover, track, and characterize Apophis as a potential impactor to exercise the planetary defense system including observations, hypothetical risk assessment and risk prediction, and hazard communication. Based on the campaign results, we present lessons learned about our ability to observe and model a potential impactor. Data products derived from astrometric observations were available for inclusion in our risk assessment model almost immediately, allowing real-time updates to the impact probability calculation and possible impact locations. An early NEOWISE diameter measurement provided a significant improvement in the uncertainty on the range of hypothetical impact outcomes. The availability of different characterization methods such as photometry, spectroscopy, and radar provided robustness to our ability to assess the potential impact risk. © 2022. The Author(s). Published by the American Astronomical Society.Brinson Foundation of ChicagoMoscow CenterNASA’s Planetary Defense Coordination Office, (80NSSC18K0284, 80NSSC18K1575, NN12AR55G)NEOOPlanetary Data SystemNational Aeronautics and Space Administration, NASA, (80NSSC18K0971)University of Maryland, UMDHorizon 2020 Framework Programme, H2020, (870403)Planetary Science Division, PSDNational Research Foundation, NRFMinistry of Education and Science of the Russian Federation, Minobrnauka, (075-15-2019-1623)National Research Foundation of Korea, NRFMinistry of Science and Higher Education of the Russian Federation, (80NSSC18K0849, FEUZ-2020-0030)Overall, the campaign successfully demonstrated the capability of the planetary defense community to respond in real time to a potentially impacting object and obtain data sufficient to characterize its orbit, brightness, size, spectrum, rotation period, and hazard to Earth. Timely reporting of astrometry and preliminary physical property analyses, with appropriate error bars, significantly improved our knowledge of the potential impact consequences. Human factors, such as the end-of-year holiday season, had a distinct impact on rapidly constraining the rotation period of Apophis and demonstrate the importance of building a broad coalition for planetary defense spanning continents and cultures. Future planetary defense campaigns should focus on targets with less-favorable apparitions that might better simulate a future discovery of a hazardous object. Acknowledgments The Apophis campaign was conducted as part of the International Asteroid Warning Network (IAWN). IAWN is supported by the Planetary Data System (PDS) Small Bodies Node (SBN) at the University of Maryland College Park. The work at the Jet Propulsion Laboratory, California Institute of Technology, was performed under a contract with the National Aeronautics and Space Administration (NASA). This material is based in part on work supported by NASA under the Science Mission Directorate Research and Analysis Programs. This publication makes use of data products from NEOWISE, which is a joint project of the University of Arizona and the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of NASA. Pan-STARRS is supported by the National Aeronautics and Space Administration under Grant No. 80NSSC18K0971 issued through the SSO Near Earth Object Observations Program. Part of this work was supported by the Russian Ministry of Science and Higher Education via the State Assignment Project FEUZ-2020-0030. Part of the observations performed with the Zeiss-1000 telescope of the Terskol Observatory Shared Research Centre of the Institute of Astronomy of the Russian Academy of Sciences. We are extremely grateful to the IRTF and GTC Observatories’ night and day staff for their overwhelming support and assistance that made the observations possible. D.P. & M.M. are thankful to Richard Binzel and Francesca DeMeo for sharing their experience and wisdom while planning and conducting the measurements. D.P. is grateful to the Israeli Space Agency. M.M. was supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0849 issued through the Planetary Astronomy Program. J.d.L., J.L., and M.P. acknowledge financial support from the NEOROCKS project, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 870403. This work was funded by NASA’s Planetary Defense Coordination Office. Supercomputing resources supporting this work were provided by the NASA High End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center. This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. ATLAS is primarily funded to search for NEAs through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575byproducts of the NEA search include images and catalogs from the survey area. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen’s University Belfast, the Space Telescope Science Institute, and the South African Astronomical Observatory. This work is partially supported by the South African National Research Foundation (NRF). Spacewatch is supported by NASA/NEOO grants and the Brinson Foundation of Chicago, IL. We thank TUBITAK National Observatory for partial support in using the T100 telescope with project number 20CT100-1743. This work was supported by the Moscow Center of Fundamental and Applied Mathematics, Agreement with the Ministry of Science and Higher Education of the Russian Federation, No. 075-15-2019-1623. This work made extensive use of Python, specifically the NumPy (Harris et al. 2020), Astropy (Astropy Collaboration et al. 2013, 2018), Matplotlib (Hunter 2007), and SciPy (Virtanen et al. 2020b) packages
J-PLUS: The Javalambre Photometric Local Universe Survey
The Javalambre Photometric Local Universe Survey (J-PLUS) is an ongoing 12-band photometric optical survey, observing thousands of square degrees of the Northern Hemisphere from the dedicated JAST/T80 telescope at the Observatorio Astrofisico de Javalambre (OAJ). The T80Cam is a camera with a field of view of 2 deg(2) mounted on a telescope with a diameter of 83 cm, and is equipped with a unique system of filters spanning the entire optical range (3500-10 000 angstrom). This filter system is a combination of broad-, medium-, and narrow-band filters, optimally designed to extract the rest-frame spectral features (the 3700-4000 angstrom Balmer break region, H delta, Ca H+K, the G band, and the Mg b and Ca triplets) that are key to characterizing stellar types and delivering a low-resolution photospectrum for each pixel of the observed sky. With a typical depth of AB similar to 21.25 mag per band, this filter set thus allows for an unbiased and accurate characterization of the stellar population in our Galaxy, it provides an unprecedented 2D photospectral information for all resolved galaxies in the local Universe, as well as accurate photo-z estimates (at the delta z/(1 + z) similar to 0.005-0.03 precision level) for moderately bright (up to r similar to 20 mag) extragalactic sources. While some narrow-band filters are designed for the study of particular emission features ([O II]/lambda 3727, H alpha/lambda 6563) up to z < 0.017, they also provide well-defined windows for the analysis of other emission lines at higher redshifts. As a result, J-PLUS has the potential to contribute to a wide range of fields in Astrophysics, both in the nearby Universe (Milky Way structure, globular clusters, 2D IFU-like studies, stellar populations of nearby and moderate-redshift galaxies, clusters of galaxies) and at high redshifts (emission-line galaxies at z approximate to 0.77, 2.2, and 4.4, quasi-stellar objects, etc.). With this paper, we release the first similar to 1000 deg(2) of J-PLUS data, containing about 4.3 million stars and 3.0 million galaxies at r < 21 mag. With a goal of 8500 deg(2) for the total J-PLUS footprint, these numbers are expected to rise to about 35 million stars and 24 million galaxies by the end of the survey