adsabs/AstroCLIMB huggingface dataset:
Paper: Lunar Laser Ranging Retroreflectors: Velocity Aberration and Diffraction Pattern
Authors: James G. Williams, Luca Porcelli, Simone Dell'Agnello, Lorenza Mauro, Marco Muccino, Douglas G. Currie, Dennis Wellnitz, Chensheng Wu, Dale H. Boggs, Nathan H. Johnson
Figure caption: The annual weighted rms residuals for each CCR for 1995 to 2022.
Paper: Lunar Laser Ranging Retroreflectors: Velocity Aberration and Diffraction Pattern
Authors: James G. Williams, Luca Porcelli, Simone Dell'Agnello, Lorenza Mauro, Marco Muccino, Douglas G. Currie, Dennis Wellnitz, Chensheng Wu, Dale H. Boggs, Nathan H. Johnson
Figure caption: Left: a new 10 cm CCR next to an Apollo 3.8 cm CCR; middle: a 10 cm CCR in a mount next to a Martian retroreflector for orbital downward ranging; right: a MoonLIGHT corner cube in a mount.
Paper: Lunar Laser Ranging Retroreflectors: Velocity Aberration and Diffraction Pattern
Authors: James G. Williams, Luca Porcelli, Simone Dell'Agnello, Lorenza Mauro, Marco Muccino, Douglas G. Currie, Dennis Wellnitz, Chensheng Wu, Dale H. Boggs, Nathan H. Johnson
Figure caption: A 10 cm NGLR CCR at the University of Maryland, with contributions to the midlatitude support structure from INFN.
Paper: Physical Properties of the Asteroid Belts from Brightness-limited Surveys
Authors: Cesar Gallegos, Cesar Fuentes, José Peña
Figure caption: The luminosity function for all asteroids is plotted in blue, and the associated uncertainty is shown in green. In red we plot the fit model with a double power law for the size distribution (Table 1), and in gray we show a random sample of 50 models in the Markov chain. In magenta we plot the best-fit power-law indices q 1 = 3.95 and q 2 = 2.27. The panels show the posterior distribution functions for the model parameters defined in Equation (13).
Paper: Physical Properties of the Asteroid Belts from Brightness-limited Surveys
Authors: Cesar Gallegos, Cesar Fuentes, José Peña
Figure caption: Normalized distribution f  r  of the mean heliocentric distance r for asteroids larger than 5 km in the MPC catalog. Asteroids in the inner, middle, and outer rings are shown in red, green, and blue, while the distribution of all asteroids is shown in black.
Paper: Physical Properties of the Asteroid Belts from Brightness-limited Surveys
Authors: Cesar Gallegos, Cesar Fuentes, José Peña
Figure caption: Distribution of properties in Peña et al. (2018). (Left) Measured size distribution f  r  assuming an albedo p = 0.134 (Ryan et al. 2015) for the 7700 surveyed objects. (Middle) For the 2464 asteroids identified in the MPC, we show the distribution of the difference between the estimated and cataloged semimajor axis f Δa . (Right) Distribution of the difference between the estimated heliocentric distance r and their ephemerides f Δr , computed using astro-aleph (Peña & Fuentes 2021).
Paper: Physical Properties of the Asteroid Belts from Brightness-limited Surveys
Authors: Cesar Gallegos, Cesar Fuentes, José Peña
Figure caption: Semimajor axis—eccentricity plot for all known objects in our sample, with arrows representing the difference between known parameters and those measured in our survey. Each arrow begins in the published MPC value and ends in the estimated (a, e) pair. In red, green, and blue, we plot the inner, middle, and outer subpopulations, respectively. In the top panel, we show the distribution of the measured semimajor axis f  a  for each subpopulation. The vertical black lines indicate the 3:1 and 5:2 Kirkwood gaps.
Paper: Physical Properties of the Asteroid Belts from Brightness-limited Surveys
Authors: Cesar Gallegos, Cesar Fuentes, José Peña
Figure caption: Corner plot for the parameter fit assuming a double power law for the size distribution of asteroids.
Paper: MIR Spectra and Analysis of Jovian Trojan Asteroids
Authors: Audrey C. Martin, Joshua P. Emery
Figure caption: (a) Mixtures of spectra of amorphous and crystalline minerals: pyroxene (PYX) on top in reds, and olivine (OLV) on the bottom in greens. Each suite has the spectra of the amorphous (am.) component mixed with the 0%–83% crystalline (xln.) component. Fully amorphous spectra are in darker shades. (b) Patroclus spectrum with three spectral mixtures overlaid: 10% xln PYX and OLV, 10% am. PYX, and 70% am OLV in green; 10% xln. PYX and OLV and 40% am. PYX and OLV in blue; and 10% xln. PYX and OLV, 70% am. PYX, and 10% am. OLV in red. Note the position shift from am. OLV–dominant spectra to am PYX–dominant spectra. (c) Patroclus spectrum with two spectral mixtures overlaid: 5% xln. PYX, 10% xln. forsterite (Fo), 15% xln. fayalite (Fa), and 80% am. OLV in yellow and 5% xln. PYX, 15% xln. Fo, 0% xln. Fa, and 80% am. OLV in green. Note the difference in the general shape of the 11 μm region when fayalite is incorporated.
Paper: MIR Spectra and Analysis of Jovian Trojan Asteroids
Authors: Audrey C. Martin, Joshua P. Emery
Figure caption: The 10 μm region spectra of Thestor and Nestor in continuum-removed space, with bars indicating the peak location of enstatite (En; red), forsterite (Fo; green), amorphous olivine (Am Olv), and potential diopside (Diop; orange) features. The continuum is modeled as a line from D8 to D12 and depicted as a gray dashed line (see Section 4.2), and the 10 μm plateau is scaled to span zero to 1 in emissivity space. We rebinned the spectra with a four bin width Gaussian smoothing function to highlight feature locations. An asterisk indicates a nonunique correlation to diopside.
Paper: MIR Spectra and Analysis of Jovian Trojan Asteroids
Authors: Audrey C. Martin, Joshua P. Emery
Figure caption: Spectral contrast of the 10 μm plateau plotted against the color index from 0.85 μm to the J band of the 11 Trojans presented here. The J band is measured from 1.1 to 1.4 μm, centered on 1.25 μm. Green symbols are less-red Trojans, and red symbols are red Trojans. The color index values are from Emery et al. (2011).
Paper: MIR Spectra and Analysis of Jovian Trojan Asteroids
Authors: Audrey C. Martin, Joshua P. Emery
Figure caption: The MIR spectrum of Deiphobus with parameter annotation. The D8 and D12 (purple) are labeled and marked with arrows. The continuum (gray) slopes upward from D8 to D12, which designate the start and end of the 10 μm plateau, respectively. The width is calculated from D8 to D12. The P10 (green) is the peak location given in Table 3, while crP10 (blue) is the 10 μm plateau peak in continuum-removed space listed in Table 4. The spectral contrast is calculated in continuum-removed space using crP10. Skew is the ratio between the right (orange) and left (red) sides of P10 as calculated in Equation (2).
Paper: MIR Spectra and Analysis of Jovian Trojan Asteroids
Authors: Audrey C. Martin, Joshua P. Emery
Figure caption: Spectra of Patroclus and Thestor plotted on top of spectra of comet nucleus 10P/Tempel 2 and comet coma 29P/Schwassmann–Wachmann 1. The comet spectra are from Kelley et al. (2017).
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: All offset white-light images from October 3 to 25, in WFM. The anti-sunward propagation of the wings can been seen more clearly in panels (c) through (e). The secondary tail becomes apparent at the outermost edge of the tail in panel (c) and is fully resolved along most of the tail in panel (d). The secondary tail is no longer observed in panels (e) and (f). Intensities are in units of 10−20 erg s−1 cm−2.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Illustration of the ejecta clumps identified within the first 48 hr post-impact in WFM (200–2500 km from system center). The images are based on the last detection of the clump, which allows for greater clarity owing to the higher radial distance from the system. The green markers denote the computed centroid for each clump. Intensities are in units of 10−20 erg s−1 cm−2. The yellow arrow indicates Sun angle, the cyan arrow represents heliocentric orbital motion of the system, and the red arrow is the DART spacecraft approach angle.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Illustration of the ejecta clumps identified within the first 6 days post-impact in NFM (20–220 km from system center). The images are based on the last detection of the clump, which allows for greater clarity owing to the higher radial distance from the system. The green markers denote the computed centroid for each clump. Intensities are in units of 10−20 erg s−1 cm−2. The yellow arrow indicates Sun angle, the cyan arrow represents heliocentric orbital motion of the system, and the red arrow is the DART spacecraft approach angle.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Grain size distribution as a function of wing detachment date, shown as ΔT in the legend. The gray dashed line represents the measured northern wing velocity, with the associated uncertainties shaded around it. The top panel depicts the entire distribution, while the bottom panel offers a zoomed-in window to more closely analyze the size distribution. We derive the bounds on grain size through locating the leftmost and rightmost markers that occupy the uncertainty threshold. The leftmost and rightmost markers are associated with the smallest and largest radii, respectively, between 0.05 and 0.2 mm, denoted by the red vertical lines.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Velocity of clump C2-S, first seen in the second MUSE WFM exposure in the southern ejecta cone edge at T03:21:05 UT 2022-09-27, tracked from third to fourth exposures. In the top and bottom panels orange lines denote the axes of the calculated centroid, which is depicted by a yellow plus sign. The bottom panel has gray and yellow lines, which show the previous position of the clump centroid and the approximate path it took to reach its current position. Both panels have marginal density plots to highlight the structure of the clump as sliced by the orange lines in each image. Intensities are in units of 10−20 erg s−1 cm−2. The green arrow is the angle toward Didymos center, and the white scale bar is distance per 1″.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Model fitting process for the primary tail (top panels) and dual tails (bottom panels), from October 3 T08:22:08 UT to October 14 T07:35:31 UT, respectively. The leftmost panels show the derotated Cartesian image, with a black solid line denoting the average position angle of the tail, a yellow dashed line for the radial midpoint of the N-summed profile, and a yellow shaded area for the range rows summed to make the profile. The middle panels depict the fit components (dashed blue is primary tail, and dashed orange is secondary tail), background contribution (dotted–dashed gray), best-fit model (solid black), original data points (red circles), and integrated flux (shaded areas). The rightmost panels demonstrate the fit components again, the central axis of each component (vertical gray dashed line), and the FWHM measurements (purple for primary tail and green for secondary tail).
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Maps of relative reflectance from NFM observations, spanning 500–750 nm and normalized at 500 nm owing to the AO lasers. The maps are oriented with north up and east to the left, the date above each map is the average date of the stack, and the reflectance slope indicated by the color bar is expressed in units of %/100 nm. The dark annuli around the sources are artifacts from our analysis, since shorter and longer wavelengths create different point-spread functions around the central condensation, which in turn created regions of negative reflectance slope (black rings). We therefore do not compare the colors of the central condensation. Clumps C6.1-S and C6.2-S are highlighted by the inset zoomed-in region, with lime arrows marking each clump.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: All white-light images from the main WFM portion of our campaign. Morphological evolution of the ejecta cone is seen in panels (b) and (g); thereafter the spirals become increasingly visible until panel (k). By panel (l), the northern spiral has detached from the central system and propagates anti-sunward until final detection in panel (n). Intensities are in units of 10−20 erg s−1 cm−2.
Paper: VLT/MUSE Characterization of Dimorphos Ejecta from the DART Impact
Authors: Brian P. Murphy, Cyrielle Opitom, Colin Snodgrass, Matthew M. Knight, Jian-Yang Li, Nancy L. Chabot, Andrew S. Rivkin, Simon F. Green, Paloma Guetzoyan, Daniel Gardener, Julia de León
Figure caption: Primary tail position angles as measured from north to east from the Lorentzian fits. Cooler colors represent earlier dates in the campaign, while warmer colors represent later dates. Uncertainties associated with the measurements are present; however, they are smaller generally than the marker size of the plot.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Latitude−longitude maps of the steady-state geopotential anomaly and wind vector fields for the strong-forcing regime (﹩{\rm{\Delta }}{{\rm{\Phi }}}_{\mathrm{eq}}/\overline{{\rm{\Phi }}}=1﹩) at reference geopotential ﹩\overline{{\rm{\Phi }}}=4\times {10}^{6}﹩ m2 s−2, averaged over the last 100 days of the simulation. The constant value of ﹩\overline{{\rm{\Phi }}}﹩ has been subtracted from each panel. Each panel in the grid corresponds to a unique combination of planetary rotation period P rot and radiative timescale τ rad. Panels share the same color scale for geopotential, but winds are normalized independently in each panel. The substellar point is located at (0°, 0°) for each panel.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Recreation of a hot Jupiter regime in Figure 3 in Perez-Becker (2013). Shown in the figure are maps of steady-state geopotential contours and the wind vector fields for the equilibrated solutions of the shallow-water model. The planetary parameters are as follows: planetary radius a = 8.2 × 107 m, planetary rotation rate Ω = 3.2 × 10−5 rad s−1 (equivalent to P rot = 2.27 days), no drag, reference geopotential ﹩\overline{{\rm{\Phi }}}=4\times {10}^{6}﹩, for strong radiative forcing (﹩{\rm{\Delta }}{{\rm{\Phi }}}_{\mathrm{eq}}/\overline{{\rm{\Phi }}}=1﹩). Three radiative timescales are depicted: τ rad = 0.1 days (left panel), τ rad = 1 day (middle panel), and τ rad = 10 days (right panel). We have subtracted the constant value of ﹩\overline{{\rm{\Phi }}}﹩ from each panel. Panels share the same color scale for geopotential, but winds are normalized independently in each panel. The substellar point is located at (0°, 0°) for each panel.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Latitude–longitude maps of the steady-state geopotential anomaly and wind vector fields for the shortest-timescale regime (radiative timescale τ rad = 0.1 days, rotation period P rot = 1 day), averaged over the last 100 days of the simulation. Each panel in the grid corresponds to a unique combination of forcing strength ﹩{\rm{\Delta }}{{\rm{\Phi }}}_{\mathrm{eq}}/\overline{{\rm{\Phi }}}﹩ and reference geopotential ﹩\overline{{\rm{\Phi }}}﹩. The wind vectors are normalized independently in each panel. The substellar point is located at (0°, 0°) for each panel. The color bar limits have been adjusted individually for each panel to ease comparison of atmospheric patterns across orders of magnitude.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Recreation of a hot Jupiter regime in Figure 3 in Perez-Becker (2013), with planetary radius turned down to a = 3a ⊕ = 1.3 × 107 m. Shown are the geopotential contour maps and the wind vector fields. The remaining planetary parameters are as follows: planetary rotation rate Ω = 3.2 × 10−5 rad s−1 (equivalent to P rot = 2.27 days), no drag, reference geopotential ﹩\overline{{\rm{\Phi }}}=4\times {10}^{6}﹩, for strong radiative forcing (﹩{\rm{\Delta }}{{\rm{\Phi }}}_{\mathrm{eq}}/\overline{{\rm{\Phi }}}=1﹩). Three radiative timescales are depicted: τ rad = 0.1 days (left panel), τ rad = 1 day (middle panel), and τ rad = 10 days (right panel). We have subtracted the constant value of ﹩\overline{{\rm{\Phi }}}﹩ from each panel. Panels share the same color scale for geopotential, but winds are normalized independently in each panel. The substellar point is located at (0°, 0°) for each panel.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: The estimated contours where τ adv = τ rad (black) and the estimated contours where Ro = 1 (gray) for different day/night contrasts of the local radiative equilibrium for the strong-forcing (solid line), medium-forcing (dashed line), and weak-forcing (dotted–dashed line) regimes. The blue crosses mark the simulated regimes. In order to compute the contours, the values for τ rad, τ adv, and Ro were averaged across the four scale heights in our ensemble. Example patterns are presented in the four corners of the parameter space. The color scale is normalized individually for each panel in order to highlight atmospheric patterns.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Mean zonal winds ﹩\overline{U}﹩ for for the shortest-timescale regime (radiative timescale τ rad = 0.1 days, rotation period P rot = 1 day), averaged over the last 100 days of the simulation. Each panel in the grid corresponds to a unique combination of forcing strength ﹩{\rm{\Delta }}{{\rm{\Phi }}}_{\mathrm{eq}}/\overline{{\rm{\Phi }}}﹩ and reference geopotential ﹩\overline{{\rm{\Phi }}}﹩. Note that the axis limits have been adjusted individually for each column in order to highlight the features for the smaller wind speeds that arise in the weak-forcing regime.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Mean zonal winds ﹩\overline{U}﹩ for the steady-state solution for the strong-forcing regime (﹩{\rm{\Delta }}{{\rm{\Phi }}}_{\mathrm{eq}}/\overline{{\rm{\Phi }}}=1﹩) at reference geopotential ﹩\overline{{\rm{\Phi }}}=4\times {10}^{6}﹩ m2 s−2, averaged over the last 100 days of the simulation. Each panel in the grid corresponds to a unique combination of planetary rotation period P rot and radiative timescale τ rad.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Snapshots of spin-up behavior for strong-forcing regime with ﹩\overline{{\rm{\Phi }}}=4\times {10}^{6}﹩ at rotation period P rot = 10 days and radiative timescale τ rad = 10 days. The hot spot is advected fully around the planet during spin-up (left column shows cyclic behavior with a period of ≈450 hr). The right column shows the equilibrating behavior. Time variability diminishes.
Paper: A Shallow-water Model Exploration of Atmospheric Circulation on Sub-Neptunes: Effects of Radiative Forcing and Rotation Period
Authors: Ekaterina Landgren, Alice Nadeau, Nikole Lewis, Tiffany Kataria, Peter Hitchcock
Figure caption: Planetary equilibrium temperature as a function of rotation period for planets around K0 (purple), K5 (blue), M0 (yellow), and M5 (red) stars. The chosen grid of rotation periods of 1, 5, and 10 days and of planetary equilibrium temperatures of 400, 800, and 1200 K generates a realistic sample. The sample region is highlighted in gray. The stellar parameters were taken from Zombeck (1990).
Paper: Physical Properties of the Asteroid Belts from Brightness-limited Surveys
Authors: Cesar Gallegos, Cesar Fuentes, José Peña
Figure caption: The size distribution is drawn in red for the inner, in green for the middle, and in blue for the outer rings. The solid lines are the best fit for each population of the model f DX. In black we plot all asteroids together. The distribution for the slope parameters is also shown.
Paper: The State of CO and CO2 Ices in the Kuiper Belt as Seen by JWST
Authors: Michael E. Brown, Wesley C. Fraser
Figure caption: Spectral models of a thin layer of CO2 particles overlying a reflective medium. Models such as these are needed to correctly reproduce the nonzero albedo at 4.1 μm where CO2 becomes essentially transparent. Slight changes in grain sizes and CO2 layer thickness give rise to many different apparent spectral types, allowing the full range of CO2 detected in the Kuiper Belt to be explained. The three models shown have background albedo, CO2 grain diameter, and CO2 layer thickness of 0.05, 2, and 2 μm (orange); 0.16, 0.7, and 10 μm (blue); and 0.23, 0.5, and 1 μm (green).
Paper: The State of CO and CO2 Ices in the Kuiper Belt as Seen by JWST
Authors: Michael E. Brown, Wesley C. Fraser
Figure caption: The real (n) and imaginary (k) indices of refraction of CO2 compared to the spectra of 2005 RN43 and 2002 TC302, which are both offset for clarity with their zero-points (shown as blue and red horizontal dashed lines, respectively). Major spectral features on both objects occur at the locations marked by dashed lines, including when the real index passes through unity, when it approaches zero, where the imaginary index peaks, and where the imaginary index returns to near zero while the real index changes rapidly.