A ground-based observation of the LCROSS impact events using the Subaru Telescope

Peng, Hong; Sugita, Seiji; Okamura, N.; Sekine, Yasuhito; Terada, Hiroshi; Takatoh, Naruhisa; Hayano, Yutaka; Fuse, Tetsuharu; Pyo, Tae‐Soo; Kawakita, Hideyo; Wooden, D. H.; Young, E. F.; Lucey, P. G.; Kurosawa, Kosuke; Genda, Hidenori; Haruyama, Junichi; Furusho, Reiko; Kadono, Toshihiko; Nakamura, Ryosuke; Kamata, Shunichi; Hamura, T.; Sekiguchi, T.; Sôma, Mitsuru; Noda, Hirotomo; Watanabe, J.

doi:10.1016/j.icarus.2011.05.008

Cited by 3 publications

(3 citation statements)

References 34 publications

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“…Aside from an enhancement of sodium in the lunar exosphere after the impact 10 , no other positive ground-based detections of the LCROSS debris plume were reported. Two groups reported non-detections from ground-based observations 11,12 .…”

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confidence: 99%

Characterization of the LCROSS impact plume from a ground-based imaging detection

et al. 2013

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The Lunar CRater Observation and Sensing Satellite (LCROSS) mission was designed to search for evidence of water in a permanently shadowed region near the lunar south pole. An instrumented Shepherding Spacecraft followed a kinetic impactor and provided -from a nadir perspective -the only images of the debris plume. With independent observations of the visible debris plume from a more oblique view, the angles and velocities of the ejecta from this unique cratering experiment are better constrained. Here we report the first visible observations of the LCROSS ejecta plume from Earth, thereby ascertaining the morphology of the plume to contain a minimum of two separate components, placing limits on ejecta velocities at multiple angles, and permitting an independent estimate of the illuminated ejecta mass. Our mass estimate implies that the lunar volatile inventory in the Cabeus permanently shadowed region includes a water concentration of 6.3 ± 1.6% by mass.

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confidence: 99%

Characterization of the LCROSS impact plume from a ground-based imaging detection

et al. 2013

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“…From these Earth-based data, Killen et al [10] detected the temporal spectral signature of sodium in the lunar exosphere, and no one reported a detection of the dust plume using standard image processing techniques [8]. Two observational campaigns presented detailed analyses of their imaging non-detections [11,12]. In their time series V-band imaging, Chanover et al [11] found that their non-detection implied a limiting plume surface brightness of 189 times fainter than the brightest illuminated surface in a foreground ridge adjacent to Cabeus.…”

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confidence: 99%

Time Series Analysis Methods and Detectability Factors for Ground-Based Imaging of the LCROSS Impact Plume

et al. 2022

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On 9 October 2009, multiple telescopes were used in a coordinated international observing campaign to acquire ground-based time series imaging to monitor the evolution of the impact plume from NASA’s Lunar CRater Observation and Sensing Satellite (LCROSS) mission. Although standard image processing techniques applied to these data were unsuccessful at detecting the presence of any impact plume, one detection was reported after processing images with Principal Component Analysis (PCA) filtering. In this work, we develop improvements to PCA filtering that increase the signal-to-noise ratio (SNR) of plume lightcurves. We use this updated methodology to remove atmospheric seeing effects not accounted for in the previous work, such as geometric distortions. We assess the robustness of PCA filtering as we search for plume detections in observations from five additional cameras in comparison with each pixel’s lightcurve during the final 40 s prior to impact to match the approximate duration of post-impact excess brightness. We explore the resulting combination of three detections and three non-detections to determine criteria for detectability in future observations of low SNR transient events. Our results indicate three observational setup constraints for optimizing the success of PCA filtering: (1) full-frame scattered light should not exceed the dynamic range between the illuminated and unilluminated surfaces, (2) the camera’s analog-to-digital conversion (ADC) should use at least 16-bit resolution, and (3) the ADC should not use gamma correction. We find that poor spatial or temporal resolution do not significantly degrade detectability, which suggests that any future LCROSS-like events may be detectable in PCA-filtered amateur observations.

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“…Lunar Reconnaissance Orbiter (LRO) passed by the impact site between the times of the Centaur and SSC impacts [ Gladstone et al , 2010]. Ground based observatories watched the event [e.g., Killen et al , 2010; Hong et al , 2011; Miller et al , 2009; Heldmann et al , 2011]. Thus, data were taken from multiple perspectives to determine the composition and quantities of materials in the ejecta.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the vapor release from the LCROSS impact: Parametric dependencies

Crider¹

2011

J. Geophys. Res.

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The Lunar Crater Observation and Sensing Satellite (LCROSS) mission included an intentional impact into the Cabeus crater, a permanently shadowed region near the Moon's south pole. The impact produced a vapor plume of volatile species liberated from the impact site. Using a Monte Carlo model to simulate the vapor plume expansion, this paper investigates the expansion as a function of the physical properties of the gas. For a thermal release scenario, the cloud expands with the highest density at the center, with the density dropping within the cloud in time as the cloud expands. When a significant non‐thermal component to the velocity (a bulk speed) exists, the vapor expands as a hemispheric shell outward from the impact site. For heavier species, the high bulk velocity produces a hemisphere of higher density of gas that appears as a ring from above. For lighter gases like H2, the thermal velocity is on the same order as the bulk velocity. If the source is prolonged, the source rate is dominant in determining the local density, however. Gases produced by photodissociation have a prolonged source close to the impact site compared to promptly produced vapors.

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A ground-based observation of the LCROSS impact events using the Subaru Telescope

Cited by 3 publications

References 34 publications

Characterization of the LCROSS impact plume from a ground-based imaging detection

Characterization of the LCROSS impact plume from a ground-based imaging detection

Time Series Analysis Methods and Detectability Factors for Ground-Based Imaging of the LCROSS Impact Plume

Modeling of the vapor release from the LCROSS impact: Parametric dependencies

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