scholarly journals Absolute colours and phase coefficients of trans-Neptunian objects: correlations and populations

2019 ◽  
Vol 488 (3) ◽  
pp. 3035-3044 ◽  
Author(s):  
Alvaro Alvarez-Candal ◽  
Carmen Ayala-Loera ◽  
Ricardo Gil-Hutton ◽  
José Luis Ortiz ◽  
Pablo Santos-Sanz ◽  
...  
Keyword(s):  
Solar System ◽  
Data Base ◽  
Relative Phase ◽  
Surface Composition ◽  
Dynamical Evolution ◽  
Initial Surface ◽  
Observational Errors ◽  
The Absolute ◽  
The Difference ◽  
Absolute Magnitudes

ABSTRACT The study of the visible colours of the trans-Neptunian objects opened a discussion almost 20 yr ago which, in spite of the increase in the amount of available data, seems far from subside. Visible colours impose constraints to the current theories of the early dynamical evolution of the Solar system such as the environment of formation, initial surface composition, and how (if) they were scattered to regions closer to the inner planets. In this paper, we present an updated version of our data base of absolute colours and relative phase coefficients for 117 objects. We define the absolute colours as the difference of the absolute magnitudes HV − HR, and the relative phase coefficient as the difference of the slopes of the phase curves Δβ. These were obtained joining our own observations plus data from the literature. The methodology has been introduced in previous works and here we expand in some interesting results, in particular the strong anticorrelation found between HV − HR and Δβ, which means that redder objects have steeper phase curves in the R filter, while bluer objects have steeper phase curves in the V filter. We analyse a series of results published in the literature in view of our data base, which is free of phase effects, and show that their statistical meaning is not very strong. We point out that phase-colouring and observational errors play an important role in the understanding of these proposed relationships.

From the Solar system comet cloud to near-Earth space

1999 ◽  
Vol 173 ◽  
pp. 339-344 ◽  
Author(s):  
V.V. Emel'yanenko
Keyword(s):  
Steady State ◽  
Solar System ◽  
Dynamical Evolution ◽  
Oort Cloud ◽  
High Eccentricity ◽  
Earth Space ◽  
Near Earth Space ◽  
Short Period ◽  
Absolute Magnitudes ◽  
Continuous Source

AbstractThe dynamical evolution of objects from different zones of the solar system comet cloud to near-Earth space has been investigated. The steady-state number of objects with perihelion distancesq< 1.5 AU and periodsP <20 yr, arising from the near-parabolic flux of comets with absolute magnitudes brighter thanH10= 7 is ∼ 200 − 1000. The corresponding number for Halley-type comets is hundreds of times larger than the number of known Halley-type comets. The flux of objects in the Centaurs zone, captured from the near-parabolic flux is 300 times as large as the flux of new comets. The total number of cometary objects with semi-major axesain the range 50 <a< 500 AU andq∼ 1 AU is ∼ 10 times as large as the number of active comets. The probability of the transfer of objects from the trans-Neptunian orbits with 35 <q< 50 AU anda∼ 600 AU into the Jupiter family is ∼ 0.0001. The calculations show that trans-Neptunian objects on high-eccentricity orbits can be a significant continuous source for both the replenishment of the Oort cloud and the capture to short-period orbits.

scholarly journals Turnoffs and Ages of Globular Clusters

1988 ◽  
Vol 126 ◽  
pp. 635-636
Author(s):  
F. Buonanno ◽  
C. E. Corsi ◽  
F. Fusi Pecci
Keyword(s):  
Globular Clusters ◽  
Horizontal Branch ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
The Absolute ◽  
The Difference ◽  
Absolute Magnitudes ◽  
Lyrae Stars ◽  
The Way

The way to arrive at (even relative) ages for globular clusters involves the determination of their (relative) distances. We would like to see a theory which would fit the absolute magnitudes of RR Lyrae stars as determined from observations (Sandage effect). We have examined a sample of 17 CM diagrams of galactic globular clusters, 11 of which were observed at ESO and reduced with the program, ROMAFOT and 6 of which were taken from the literature. In Fig. 1 the difference in bolometric magnitude between the turnoff point and the location of the zero-age horizontal branch (ZAHB), δV RRTO (bo1) is plotted versus [Fe/H]. It turns out that δV RRTO ≃ δ RRTO (bo1) + 0.1 = 3.56 ±0.15. We are faced with the problem of determining how the horizontal branch scales with metallicity in order to understand the constant value of 3.56 in this relation.

scholarly journals The Luminosities of Horizontal Branches and RR Lyrae Stars in Globular Clusters

2004 ◽  
Vol 193 ◽  
pp. 525-529 ◽  
Author(s):  
D.H. McNamara ◽  
M.B. Rose ◽  
P.J. Brown ◽  
D.I. Ketcheson ◽  
J.E. Maxwell ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Absolute Magnitude ◽  
Apparent Magnitude ◽  
Rr Lyrae Stars ◽  
Blue Stragglers ◽  
Rr Lyrae ◽  
The Absolute ◽  
The Difference ◽  
Absolute Magnitudes ◽  
Lyrae Stars

AbstractWe have utilized the latest stellar models of the Y2 (Yonsei-Yale) collaborators and color-magnitude diagrams of globular clusters to infer ages and absolute magnitudes of their horizontal branches (HB). The intrinsic (B – V) color indices of the turn-offs, of the globular clusters were used to find ages. For 47 clusters that appear to be coeval (within ±0.7 Gyr), we find an average age of 12.5 Gyr. We adopt this age and infer the absolute magnitudes of the turn-offs, from the clusters [Fe/H] values. The absolute magnitude of the horizontal branches or RR Lyrae stars are then determined from the difference between the apparent magnitudes of the horizontal branches (or RR Lyrae stars) and the apparent magnitude of the turn-offs, VTO. We conclude: 1) The slope of the MV(HB), [Fe/H] relation is ~0.3 for clusters with [Fe/H] values between —0.5 to —1.5. The relation has zero slope for [Fe/H] values smaller than −1.5. 2) For [Fe/H] < -1.3, the MV(HB) or MV values of RRLyrae stars are not only a function of [Fe/H], but the horizontal-branch type in the sense that the clusters with the blue horizontal branches have more luminous horizontal branches than clusters with red horizontal branches. The same results are found by inferring the luminosities of the HBs from pulsating blue stragglers.

scholarly journals Surface composition and dynamical evolution of two retrograde objects in the outer solar system: 2008 YB3and 2005 VD

2013 ◽  
Vol 550 ◽  
pp. A13 ◽  
Author(s):  
N. Pinilla-Alonso ◽  
A. Alvarez-Candal ◽  
M. D. Melita ◽  
V. Lorenzi ◽  
J. Licandro ◽  
...  
Keyword(s):  
Solar System ◽  
Surface Composition ◽  
Dynamical Evolution ◽  
Outer Solar System

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

Translocation Relative to Range

Methodology ◽  
2008 ◽  
Vol 4 (3) ◽  
pp. 132-138 ◽  
Author(s):  
Michael Höfler
Keyword(s):  
Risk Difference ◽  
Binary Outcomes ◽  
Number Needed To Treat ◽  
Likert Scales ◽  
Psychological Science ◽  
The Absolute ◽  
The Difference ◽  
Variance Parameters ◽  
Standardized Index ◽  
Maximum Possible Magnitude

A standardized index for effect intensity, the translocation relative to range (TRR), is discussed. TRR is defined as the difference between the expectations of an outcome under two conditions (the absolute increment) divided by the maximum possible amount for that difference. TRR measures the shift caused by a factor relative to the maximum possible magnitude of that shift. For binary outcomes, TRR simply equals the risk difference, also known as the inverse number needed to treat. TRR ranges from –1 to 1 but is – unlike a correlation coefficient – a measure for effect intensity, because it does not rely on variance parameters in a certain population as do effect size measures (e.g., correlations, Cohen’s d). However, the use of TRR is restricted on outcomes with fixed and meaningful endpoints given, for instance, for meaningful psychological questionnaires or Likert scales. The use of TRR vs. Cohen’s d is illustrated with three examples from Psychological Science 2006 (issues 5 through 8). It is argued that, whenever TRR applies, it should complement Cohen’s d to avoid the problems related to the latter. In any case, the absolute increment should complement d.

The Issue of Sustainability in Third World Food Production (The Distinguishedl Lecture)

1992 ◽  
Vol 31 (4I) ◽  
pp. 511-534
Author(s):  
Winfried Von Urff
Keyword(s):  
Developing Countries ◽  
Population Growth ◽  
Food Production ◽  
Third World ◽  
Total Population ◽  
Absolute Number ◽  
Comprehensive Analysis ◽  
World Food ◽  
The Absolute ◽  
The Difference

In spite of the fact that food production in developing countries doubled over the last 25 years undernutrition is still widely spread. At the beginning of the eighties, according to FAO, 335 to 494 million people in developing countries suffered from serious undernutrition the difference being due to different concepts to determine undernutrition on which scientist were unable to find a consensus.) Unfortunately there is no recent comprehensive analysis of the food situation comparable to those of previous World Food Surveys but it can be taken for sure that the absolute number of undernourished has increased. According to unofficial FAO sources a figure of 870 million was estimated for 1990 (22 percent of the total population in developing countries) using the same concept that led to the figure of 494 million in 1979-81 (23 percent of the total population in developing countries) which means that most probably the number of undernourished increased at a rate slightly less than population growth.

Mathematical models of Gauss – Kruger projection for calculation of meridians conversion on the plane and scale of the image

2018 ◽  
Vol 934 (4) ◽  
pp. 2-7
Author(s):  
P.A. Medvedev ◽  
M.V. Novgorodskaya
Keyword(s):  
Mathematical Models ◽  
Analytical Methods ◽  
Theoretical Studies ◽  
Spherical Trigonometry ◽  
Cylindrical Projection ◽  
Rectangular Coordinates ◽  
In Series ◽  
Observational Errors ◽  
The Difference

This work contains continued research carried out on improving mathematical models of the Gauss-Krueger projection in accordance with the parameters of any ellipsoid with the removal of points from the axial meridian to l ≤ 6° . In terms of formulae earlier derived by the authors with improved convergence for the calculation of planar rectangular coordinates by geodesic coordinates, the algorithms for determining the convergence of meridians on the plane and the scale of the image are obtained. The improvement of the formulae represented in the form of series in powers of the difference in longitudes was accomplished by separating spherical terms in series and then replacing their approximate sums by exact expressions using the formulae of spherical trigonometry. As in previous works published in this journal [7, 8], determining the sums of the spherical terms was carried out according to the laws of the transverse-cylindrical projection of the sphere on the plane. Theoretical studies are given and formulae are proposed for estimating the observational errors in the results of the derived algorithms. The maximum of observational errors of convergence of meridians and scale, proceeding from the specified accuracy of the determined quantities was established through analytical methods.

scholarly journals Observed Relations Between Physical Properties and MK Classification as Functions of Metal Abundance for F5-K4 Stars

1976 ◽  
Vol 72 ◽  
pp. 75-78
Author(s):  
M. Grenon
Keyword(s):  
Physical Properties ◽  
Spectral Range ◽  
Spectral Type ◽  
Photometric System ◽  
Luminosity Class ◽  
Empirical Relations ◽  
Metal Abundance ◽  
Systematic Effects ◽  
The Absolute ◽  
Absolute Magnitudes

The Geneva photometric system has been calibrated in terms of [M/H], θeff, Mv in the spectral range F5 to K4. As the spectral type is a datum generally available, we derive empirical relations showing the coupling of θeff and [M/H] at given spectral type and luminosity class. Similar relations are offered for the absolute magnitudes and provide a more accurate means for deriving spectroscopic parallaxes. Systematic effects on the estimation of the luminosity class are also shown.

scholarly journals The Absolute Magnitude of the Early-Type MK Standards From Hipparcos Parallaxes

1998 ◽  
Vol 11 (1) ◽  
pp. 566-566
Author(s):  
C. Jaschek ◽  
A.E. Gómez
Keyword(s):  
Main Sequence ◽  
Rotational Velocity ◽  
Wide Band ◽  
Absolute Magnitude ◽  
Interstellar Extinction ◽  
Early Type ◽  
Class V ◽  
Luminosity Class ◽  
The Absolute ◽  
Absolute Magnitudes

We have analysed the standards of the MK system in the B0-F5 spectral region with the help of Hipparcos parallaxes, using only stars for which the error on the absolute magnitude is ≤ 0.3 mag. The sample stars (about one hundred) were scrutinized for companions and for interstellar extinction. We find that the main sequence is a wide band and that, although in general giants and dwarfs have different absolute magnitudes, the separation between luminosity class V and III is not clear. We conclude that there is no strict relation between luminosity class and absolute magnitude. The relation is only a statistical one and has a large intrinsic dispersion. We have analysed similarly the system of standards defined by Garrison and Gray (1994) separating low and high rotational velocity standards. We find similar effects as in the original MK system.

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