There were no new TNO/Centaur/SDO discoveries announced since the previous issue of Distant EKOs.
Deleted/Re-identified objects:
2003 UW292 = 2005 UN524
Current number of TNOs: 1093 (including Pluto)
Current number of Centaurs/SDOs: 243
Current number of Neptune Trojans: 6
Out of a total of 1342 objects:
548 have measurements from only one opposition
538 of those have had no measurements for more than a year
288 of those have arcs shorter than 10 days
(for more details, see:
http://www.boulder.swri.edu/ekonews/objects/recov_stats.jpg)
Over one thousand objects have so far been discovered orbiting beyond Neptune. These trans-Neptunian objects (TNOs) represent the primitive remnants of the planetesimal disk from which the planets formed and are perhaps analogous to the unseen dust parent-bodies in debris disks observed around other main-sequence stars. The dynamical and physical properties of these bodies provide unique and important constraints on formation and evolution models of the Solar System. While the dynamical architecture in this region (also known as the Kuiper Belt) is becoming relatively clear, the physical properties of the objects are still largely unexplored. In particular, fundamental parameters such as size, albedo, density and thermal properties are difficult to measure. Measurements of thermal emission, which peaks at far-IR wavelengths, offer the best means available to determine the physical properties. While Spitzer has provided some results, notably revealing a large albedo diversity in this population, the increased sensitivity of Herschel and its superior wavelength coverage should permit profound advances in the field.
Within our accepted project we propose to perform radiometric measurements of 139 objects, including 25 known multiple systems. When combined with measurements of the dust population beyond Neptune (e.g. from the New Horizons mission to Pluto), our results will provide a benchmark for understanding the Solar debris disk, and extra-solar ones as well.
To appear in: Earth, Moon and Planets, Issue 105 (2009 August)
For preprints, contact tmueller@mpe.mpg.de
The Nice model of Gomes et al. suggests that the migration of the giant
planets caused a planetesimal clearing event which led to the Late Heavy
Bombardment (LHB) at 880 Myr. Here we investigate the IR emission from
the Kuiper belt during the history of the Solar System as described by
the Nice model. We describe a method for easily converting the results
of N-body planetesimal simulations into observational properties
(assuming black-body grains and a single size distribution) and further
modify this method to improve its realism (using realistic grain
properties and a three-phase size distribution). We compare our results
with observed debris discs and evaluate the plausibility of detecting an
LHB-like process in extrasolar systems. Recent surveys have shown that
4% of stars exhibit 24 
m excess and 16% exhibit 70 m excess.
We show that the Solar System would have been amongst the brightest of
these systems before the LHB at both 24 and 70 m. We find a
significant increase in 24 m emission during the LHB, which rapidly
drops off and becomes undetectable within 30 Myr, whereas the 70 m
emission remains detectable until 360 Myr after the LHB. Comparison with
the statistics of debris disc evolution shows that such depletion events
must be rare occurring around less than 12% of Sun-like stars and with
this level of incidence we would expect approximately one of the 413
Sun-like, field stars so far detected to have a 24 m excess to be
currently going through an LHB. We also find that collisional processes
are important in the Solar System before the LHB and that parameters for
weak Kuiper belt objects are inconsistent with the Nice model
interpretation of the LHB.
To appear in: Monthly Notices of the Royal Astronomical Society
For preprints, contact mbooth@ast.cam.ac.uk
or on the web at http://uk.arxiv.org/abs/0906.3755
Trans-Neptunian objects (TNOs) orbiting in the Edgeworth-Kuiper Belt
carry precious information about the origin and evolution of the Solar
System. The Kuiper Belt has a very complex orbital structure. Indeed,
TNOs exhibit surprisingly large eccentricities, e, and inclinations,
i, and are classified in distinct dynamical classes. Here we propose
that the Kuiper Belt orbital structure can be explained by a massive
scattered planetesimal with tenths of the Earth's mass, which later
remained in the system in a distant stable orbit (an outer planet). Near
the end of planet formation, the outer planet was firstly scattered by
one of the icy giant planets, then it dynamically excited the primordial
planetesimal disk over at least tens of Myr, reproducing the levels
observed at 40-50 AU and the truncation of the disk at about 48 AU
before planet migration. Later, the outer planet was captured by a
distant resonance with Neptune of the type r:1 or r:2 (e.g., 6:1, 7:1,
...), acquiring an inclined stable orbit (=100 AU; 20-40
), thus
preserving the Kuiper Belt over 
4 Gyr. Our model explains the
following: 1) Depletion of the inner Kuiper Belt; 2) The entire
currently known resonant populations in the Kuiper Belt, including
Neptune Trojans and resonant TNOs in distant resonances (>50 AU); 3)
Formation of scattered and detached TNOs, including analogues of
(136199) Eris, 2004 XR190, (148209) 2000 CR105, and (90377) Sedna; 4)
Classical TNOs and their dual nature of cold and hot populations; 5)
Orbital excitation of classical TNOs; 6) The Kuiper Belt outer edge at
about 48 AU; 7) Loss of 99% of the initial total mass of the
Kuiper Belt through dynamical depletion and enhanced collisional
grinding; 8) Neptune's current orbit at 30.1 AU. In summary, our
scenario consistently reproduces all main aspects of Kuiper Belt
architecture with unprecedented detail. The best constraints obtained
from the model for the outer planet are: aP=100-175 AU (currently
near or inside an r:1 or r:2 resonance), qP>80 AU,
, and apparent magnitude
mag
at perihelion (assuming an albedo of 0.1-0.3 and qP=80-90 AU).
Published in: Advances in Geosciences, Volume 15 (Planetary Science), 293
For preprints, contact patryksan@gmail.com
or on the web at
http://sites.google.com/site/patryksofialykawka/
In recent years, many binary minor planets (BMPs) have been discovered in the solar system. Many models have been suggested for their formation, but these encounter difficulties explaining their observed characteristics. Here, we show that secular perturbations by the Sun (Kozai mechanism) fundamentally change the evolution and the initial distribution of BMPs predicted by such models and lead to unique observational signatures. The Kozai mechanism can lead to a large periodic oscillations in the eccentricity and inclination of highly inclined BMP orbits, where we predict such effects to be observable with current accuracy within a few years (e.g., for the binary asteroid Huenna). In addition, the combined effects of the Kozai mechanism and tidal friction (KCTF) drives BMPs into short-period circular orbits. We predict a specific inclination-dependent distribution of the separation and eccentricity of BMPs, due to these effects, including a zone of avoidance at the highest inclinations. Specifically, the Kozai evolution could explain the recently observed peculiar orbit of the Kuiper Belt binary 2001 QW322. Additionally, the KCTF process could lead to BMPs coalescence and serve as an important route for the formation of irregular shaped single minor planets with large axial tilts.
Published in: The Astrophysical Journal Letters, 699, L17 (2009 July 1)
Preprints available on the web at
http://arxiv.org/abs/0809.2095
On the basis of their orbital elements, present-day Kuiper belt objects can be grouped into distinct dynamical classes: classical, resonant and scattered ones. Jiang and Yeh have proposed gas-drag-induced resonant capture in a protostellar disc analogous to the primordial solar nebula as a mechanism able to explain the dominant 3:2 resonant population observed in Kuiper belt objects. de la Fuente Marcos and de la Fuente Marcos further investigated the drag-induced mechanism numerically. Our significant contribution is a hydrodynamic theory derivation of results obtained in the Jiang and Yeh, and de la Fuente Marcos and de la Fuente Marcos numerical simulations.
Published in: Monthly Notices of the Royal Astronomical Society, 396, 1032
For preprints, contact griv@bgu.ac.il or jiang@phys.nthu.edu.tw
The Centaurs are a transient population of small bodies in the outer
solar system whose orbits are strongly chaotic. These objects
typically suffer significant changes of orbital parameters on timescales
of a few thousand years, and their orbital evolution exhibits two types
of behaviors described qualitatively as random-walk and
resonance-sticking. We have analyzed the chaotic behavior of the known
Centaurs. Our analysis has revealed that the two types of chaotic
evolution are quantitatively distinguishable: (1) the random walk-type
behavior is well described by so-called generalized diffusion in which
the rms deviation of the semimajor axis grows with time t as 
, with Hurst exponent H in the range 0.22-0.95, however (2)
orbital evolution dominated by intermittent resonance sticking, with
sudden jumps from one mean motion resonance to another, has poorly
defined H. We further find that these two types of behavior are
correlated with Centaur dynamical lifetime: most Centaurs whose
dynamical lifetime is less than 22 Myr exhibit generalized
diffusion, whereas most Centaurs of longer dynamical lifetimes exhibit
intermittent resonance sticking. We also find that Centaurs in the
diffusing class are likely to evolve into Jupiter-family comets during
their dynamical lifetimes, while those in the resonance-hopping class do
not.
To appear in: Icarus
For preprints, contact renu@lpl.arizona.edu
or on the web at http://arxiv.org/abs/0906.4795
We present the results of detailed dynamical simulations of the effect
of the migration of the four giant planets on both the transport of
pre-formed Neptune Trojans, and the capture of new Trojans from a
trans-Neptunian disk. The cloud of pre-formed Trojans consisted of
thousands of massless particles placed on dynamically cold orbits around
Neptune's L4 and L5 Lagrange points, while the trans-Neptunian disk
contained tens of thousands of such particles spread on dynamically cold
orbits between the initial and final locations of Neptune. Through
comparison of the results with previous work on the known Neptunian
Trojans, we find that scenarios involving the slow migration of Neptune
over a large distance (50 Myr to migrate from 18.1 AU to its current
location, using an exponential-folding time of t = 10 Myr) provide the
best match to the properties of the known Trojans. Scenarios with faster
migration (5 Myr, with t = 1 Myr), and those in which Neptune migrates
from 23.1 AU to its current location, fail to adequately reproduce the
current day Trojan population. Scenarios which avoid disruptive
perturbation events between Uranus and Neptune fail to yield any
significant excitation of pre-formed Trojans (transported with
efficiencies between 30% and 98% whilst maintaining the dynamically
cold nature of these objects - e < 0.1, 
). Conversely,
scenarios with periods of strong Uranus-Neptune perturbation lead to the
almost complete loss of such pre-formed objects. In these cases, a small
fraction (0.15%) of these escaped objects are later recaptured as
Trojans prior to the end of migration, with a wide range of
eccentricities (<0.35) and inclinations (
). In all
scenarios (including those with such disruptive interaction between
Uranus and Neptune) the capture of objects from the trans-Neptunian disk
(through which Neptune migrates) is achieved with efficiencies between
0.1% and 1%. The captured Trojans display a wide range of
inclinations ( for slow migration, and 
for rapid
migration) and eccentricities (<0.35), and we conclude that, given the
vast amount of material which undoubtedly formed beyond the orbit of
Neptune, such captured objects may be sufficient to explain the entire
Neptune Trojan population.
To appear in: Monthly Notices of the Royal Astronomical Society
For preprints, contact patryksan@gmail.com
or on the web at
http://sites.google.com/site/patryksofialykawka/
The stability of Trojan type orbits around Neptune is studied. As the
first part of our investigation, we present in this paper a global view
of the stability of Trojans on inclined orbits. Using the frequency
analysis method based on the FFT technique, we construct high resolution
dynamical maps on the plane of initial semimajor axis a0 versus
inclination i0. These maps show three most stable regions, with i0
in the range of
and
respectively, where the Trojans are most probably
expected to be found. The similarity between the maps for the leading
and trailing triangular Lagrange points L4 and L5 confirms the
dynamical symmetry between these two points. By computing the power
spectrum and the proper frequencies of the Trojan motion, we figure out
the mechanisms that trigger chaos in the motion. The Kozai resonance
found at high inclination varies the eccentricity and inclination of
orbits, while the 
secular resonance around
pumps up the eccentricity. Both mechanisms lead to eccentric orbits and
encounters with Uranus that introduce strong perturbation and drive the
objects away from the Trojan like orbits. This explains the clearance of
Trojan at high inclination (
) and an unstable gap around
on the dynamical map. An empirical theory is derived from the
numerical results, with which the main secular resonances are located on
the initial plane of (a0,i0). The fine structures in the dynamical
maps can be explained by these secular resonances.
To appear in: Monthly Notices of the Royal Astronomical Society
For preprints, contact zhouly@nju.edu.cn
or on the web at http://arxiv.org/abs/0906.5075
Recently, the first collisional family was discovered in the Kuiper
belt. The parent body of this family, Haumea, is one of the largest
objects in the Kuiper belt and is orbited by two satellites. It has been
proposed that the Haumea family was created from dispersed fragments
that resulted from a giant impact. This proposed origin of the Haumea
family is however in conflict with the observed velocity dispersion
between the family members (140 m/s) which is significantly less
than the escape velocity from Haumea's surface (900 m/s). In this
paper we propose a different formation scenario for Haumea's collisional
family. In our scenario the family members are ejected while in orbit
around Haumea. This scenario, therefore, gives naturally rise to a lower
velocity dispersion among the family members than expected from direct
ejection from Haumea's surface. In our scenario Haumea's giant impact
forms a single moon that tidally evolves outward until it suffers a
destructive collision from which the family is created. We show that
this formation scenario yields a velocity dispersion of 190 m/s
among the family members which is in good agreement with the
observations. We discuss an alternative scenario that consists of the
formation and tidal evolution of several satellites that are ejected by
collisions with unbound Kuiper belt objects. However, the formation of
the Haumea family in this latter way is difficult to reconcile with the
large abundance of Kuiper belt binaries. We therefore favor forming the
family by a destructive collision of a single moon of Haumea. The
probability for Haumea's initial giant impact in todays Kuiper belt is
less than 10-3. In our scenario, however, Haumea's giant impact
can occur before the excitation of the Kuiper belt and the ejection of
the family members afterwards. This has the advantage that one can
preserve the dynamical coherence of the family and explain Haumea's
original giant impact, which is several orders of magnitude more likely
to have occurred in the primordial dynamically cold Kuiper belt compared
to the dynamically excited Kuiper belt today.
Published in: The Astrophysical Journal, 700, 1242 (2009 August)
For preprints, contact hes@astro.caltech.edu
Kuiper Belt Objects and cometary nuclei are considered among the most pristine bodies of the outer solar system. However, the composition of these objects might not reflect that of the planetesimals from which they accreted. They have experienced some collisional activity since the formation of the Edgeworth-Kuiper Belt, leading to a possible alteration of their structure and composition. Here, we examine the possible alteration of icy bodies (10 to 100 km radii) located in the primitive Edgeworth-Kuiper Belt due to the heat generated by collisions of planetesimals with sizes not exceeding 10% of the target body. We use a cometary nucleus model initially made of a mixture of amorphous ice and dust to investigate the influence of the target's intrinsic properties on its post-impact thermodynamical evolution. We show that multiple collisions must be considered over long periods to trigger a continuous crystallization within a target owning a typical cometary composition. However, the collision rates we have determined are approximately 1000 times greater than those predicted for the current collisional environment in the Edgeworth-Kuiper Belt. This implies that the collisional processes that occurred over the age of the Solar System did not produce any phase transition of H2O ice from amorphous to crystalline form in cometary size bodies located in the primitive Edgeworth-Kuiper Belt.
Published in: Monthly Notices of the Royal Astronomical Society, 397, L74
For preprints, contact marboeuf@obs-besancon.fr
We investigate the internal thermal evolution of Kuiper belt objects
(KBOs), small (radii < 1000 km), icy (mean densities
< 2500 kg m-3) bodies orbiting beyond Neptune, focusing on
Pluto's moon Charon in particular. Our calculations are
time-dependent and account for differentiation. We review evidence for
ammonia hydrates in the ices of KBOs, and include their effects on the
thermal evolution. A key finding is that the production of the first
melt, at the melting point of ammonia dihydrate, 
176 K,
triggers differentiation of rock and ice. The resulting structure
comprises a rocky core surrounded by liquids and ice, enclosed within
a > 100 km thick undifferentiated crust of rock and ice. This
structure is especially conducive to the retention of subsurface
liquid, and bodies the size of Charon or larger (radii > 600 km) are
predicted to retain some subsurface liquid to the present day. We
discuss the possibility that this liquid can be brought to the surface
rapidly via self-propagating cracks. We conclude that cryovolcanism
is a viable process expected to affect the surfaces of large KBOs
including Charon.
Published in: Icarus, 202, 694 (2009 August)
Aims. We investigate the surface composition of the Plutino (47171) 1999 TC36.
Methods. We completed near-infrared photometric and spectroscopic observations of (47171) 1999 TC36 with the adaptive optics instrument NACO at the ESO VLT during 12 October 2006, and present these data with ISAAC and SINFONI spectroscopic observations carried out about one month later on 9 November 2006 and 8 November 2006, respectively. The ISAAC and SINFONI spectroscopic observations were combined with a visible spectrum obtained by FORS1 on 9 November 2006. Composition and properties of the compounds present on the surface of the target are investigated by applying a Hapke radiative transfer model to the measured spectra and to previously published observations.
Results. We present the relative reflectance spectrum of
(47171) 1999 TC36 in the wavelength range (0.37-2.33) 
. An intimate
mixture of Triton tholin, Titan tholin, serpentine, and Triton tholin
diluted in water ice represents the best-fit model description of the
measured spectrum. Any significant differences from the published
spectra of (47171) 1999 TC36 taken on 2001 and 2003 could be due to
surface heterogeneity.
Published in: Astronomy & Astrophysics, 501, 375 (2009 July)
Aims. The objective of this work is to investigate the physical
properties of objects beyond Neptune -- the new frontiers of the Solar
System -- and in particular to study the surface composition of (50000)
Quaoar, a classical Transneptunian (or Kuiper Belt) object. Because of
its distance from the Sun, Quaoar is expected to have preserved, to a
degree, its original composition. Our goals are to determine to what
degree this is true and to shed light on the chemical evolution of this
icy body.
Methods. We present new near-infrared (3.6 and 4.5 m)
photometric data obtained with the Spitzer Space Telescope. These data
complement high resolution, low signal-to-noise spectroscopic and
photometric data obtained in the visible and near-infrared
(0.4-2.3 m) at VLT-ESO and provide an excellent set of constraints
in the model calculation process. We perform spectral modeling of the
entire wavelength range -- from 0.3 to 4.5 m by means of a code
based on the Shkuratov radiative transfer formulation of the slab model.
We also attempt to determine the temperature of H2O ice making use of
the crystalline feature at 1.65 m.
Results. We present a model confirming previous results regarding the presence of crystalline H2O and CH4 ice, as well as C2H6 and organic materials, on the surface of this distant icy body. We attempt a measurement of the temperature and find that stronger constraints on the composition are needed to obtain a precise determination.
Conclusions. Model fits indicate that N2 may be a significant
component, along with a component that is bright at
m,
which we suggest at this time could be amorphous H2O ice in tiny
grains or thin grain coatings. Irradiated crystalline H2O could be
the source of small-grained amorphous H2O ice. The albedo and
composition of Quaoar, in particular the presence of N2, if
confirmed, make this TNO quite similar to Triton and Pluto.
Published in: Astronomy & Astrophysics, 501, 349 (2009 July)
Kuiper Belt dwarf planet 136472 Makemake, formerly known as 2005 FY9, is
currently the third-largest known object in the Kuiper Belt, after the
dwarf planets Pluto and Eris. It is currently second only to Pluto in
apparent brightness, due to Eris' much larger heliocentric distance.
Makemake shows very little photometric variability, which has prevented
confident determination of its rotation period until now. Using
extremely precise time-series photometry, we find that the rotation
period of Makemake is
hr, where the uncertainty is a
90% confidence interval. An alias period is detected at 11.41 hr, but
is determined with approximately 95% confidence not to be the true
period. Makemake's 7.77 hr rotation period is in the typical range for
Kuiper Belt objects, consistent with Makemake's apparent lack of a
substantial satellite to alter its rotation through tides. The amplitude
of Makemake's photometric light curve is
mag in V.
This amplitude is about 10 times less than Pluto's, which is surprising
given the two objects' similar sizes and spectral characteristics.
Makemake's photometric variability is instead similar to that of Eris,
which is so small that no confident rotation period has yet been
determined. It has been suggested that dwarf planets such as Makemake
and Eris, both farther from the Sun and colder than Pluto, exhibit lower
photometric variability because they are covered with a uniform layer of
frost. Such a frost is probably the correct explanation for Eris.
However, it may be inconsistent with the spectrum of Makemake, which
resembles reddish Pluto more than neutrally colored Eris. Makemake may
instead be a more Pluto-like object that we observe at present with a
nearly pole-on viewing geometry -- a possibility that can be tested
with continuing observations over the coming decades.
Published in: The Astronomical Journal, 138, 428 (2009 August)
1 Dept. of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104, USA
2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
3 Initiative in Innovative Computing at Harvard, 60 Oxford Street, Cambridge, MA 02138, USA
4 Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan
We conducted a search for occultations of bright stars by Kuiper Belt
Objects (KBOs) to estimate the density of sub-km KBOs in the sky. We
report here the first results of this occultation survey of the outer
solar system conducted in 2007 June and 2008 June/July at the MMT
Observatory using Megacam, the large MMT optical imager. We used Megacam
in a novel shutterless continuous-readout mode to achieve high
precision photometry at 200 Hz, which with point-spread function
convolution results in an effective sampling of
. We
present an analysis of 220 star hours at signal-to-noise ratio of 25 or
greater, taken from images of fields within 
of the ecliptic
plane. The survey efficiency is greater than 10% for occultations by
KBOs of diameter 
km, and we report no detections in our
data set. We set a new 95% confidence level upper limit for the surface
density 
of KBOs larger than 1 km:
, and for KBOs
larger than
.
Published in: The Astronomical Journal, 138, 568 (2009 August)
For preprints, contact fbianco@cfa.harvard.edu
We apply scintillation theory to stellar signal fluctuations in the high-resolution, high signal/noise, dual-wavelength data from the MMT observation of the 2007 March 18 occultation of P445.3 by Pluto. A well-defined high wavenumber cutoff in the fluctuations is consistent with viscous-thermal dissipation of buoyancy waves (internal gravity waves) in Pluto’s high atmosphere, and provides strong evidence that the underlying density fluctuations are governed by the gravity-wave dispersion relation.
To appear in: Icarus
For preprints, contact hubbard@lpl.arizona.edu
or on the web at http://arxiv.org/abs/0906.4141
This thesis discusses research into four different orbital dynamics problems, where the main goal of each chapter is to characterize the strongest non-Keplerian effect. These problems are introduced and discussed in Chapter 1, to help provide context for the subsequent chapters. In Chapter 2, I discuss a new technique for probing the interior density distributions of extra-solar planets by observing apsidal precession. Using a detailed theoretical and observational model of this precession, I conclude that NASA's Kepler mission will be able to detect the presence or absence of a massive core in very hot Jupiters with eccentricities greater than 0.003. The remaining chapters discuss the orbital dynamics of Kuiper belt objects (KBOs) orbiting the Sun beyond Neptune. The family of dwarf planet Haumea (2003 EL61) is characterized in Chapter 3, including a list of candidate family members sorted by dynamical proximity. Using a numerical integration of resonance diffusion, I also show that the Haumea family is at least 1 Gyr old and is probably primordial. In Chapter 4, I analyze and fit astrometric data for the two satellites of Haumea (Hi'iaka and Namaka) to determine their orbital properties and the masses of Haumea and Hi'iaka. The implications of the new orbital solution are discussed, including the exciting conclusion that Haumea and Namaka are currently starting a season of mutual events. A more general investigation of the orbital and tidal evolution of KBO binaries is given in Chapter 5. A new orbital evolution model is described that accounts for perturbations from the Sun, self-consistent tidal evolution, and non-hydrostatic quadrupoles of solid KBOs. Using this model, I find that the orbital parameters of KBO binaries may have been modified significantly over the age of the solar system. Applied to the Orcus-Vanth binary, this model shows that a short-period circular orbit does not necessarily imply a collisional formation. In all, the work in this thesis has sought to analyze observational data by using the theoretical tools of orbital dynamics.
Dissertation advised by Michael E. Brown
Ph.D. awarded June, 2009 from California Institute of Technology
Now working as a postdoctoral researcher with Matthew Holman. New address as of July 2009:
Darin Ragozzine
Harvard-Smithsonian Center for Astrophysics
60 Garden Street, MS-51
Cambridge, MA 02138
Entire thesis available on the web at
http://etd.caltech.edu/etd/available/etd-05282009-164537/
We accept submissions for the following sections:
Distant EKOs is not a refereed publication, but is a tool for furthering communication among people interested in Kuiper belt research. Publication or listing of an article in the Newsletter or the web page does not constitute an endorsement of the article's results or imply validity of its contents. When referencing an article, please reference the original source; Distant EKOs is not a substitute for peer-reviewed journals.
