FG Planetengeodäsie

17 Items

Recent Submissions
Lateral variations in bulk density and porosit of the upper lunar crust from high-resolution gravity and topography data: Comparison of different analysis techniques

Wahl, Daniel ; Oberst, Jürgen (2019-05-29)

We map lateral variations in bulk density of the upper lunar highland crust using the most recent GRAIL gravity field solution of degree and order 1500 in combination with LOLA topography data, both truncated to an upper limit of degree and order 700. Our maps have a spatial resolution of 0.75°, where each grid point was calculated using circular analysis regions of 3° radius. We apply two meth...

Density and porosity of the upper lunar crust from combined analysis of gravity and topography data

Wahl, Daniel (2021)

Lateral variations in bulk density of the upper lunar crust are estimated using high resolution gravity data from Gravity Recovery and Interior Laboratory (GRAIL) mission in combination with topography data obtained by the laser altimeter (LOLA) on board of Lunar Reconnaissance Orbiter (LRO). Two different methods for estimating the bulk density are compared: The first approach focuses on minim...

Temperatures near the lunar poles and their correlation with hydrogen predicted by LEND

Gläser, Philipp (2020)

We modeled temperatures for eight selected regions at the lunar poles for a total of 30 layers, from the surface down to two meters depth. For each region and depth layer we determined where water ice could be stable, i.e. where temperature is below 110 K. The areas of potential water ice were then compared to hydrogen maps derived from data of the Lunar Exploration Neutron Detector (LEND). The...

Determination of the lunar body tide from global laser altimetry data

Thor, Robin N. ; Kallenbach, Reinald ; Christensen, Ulrich R. ; Gläser, Philipp ; Stark, Alexander ; Steinbrügge, Gregor ; Oberst, Jürgen (2020-12-23)

We use global data from the Lunar Orbiter Laser Altimeter (LOLA) to retrieve the lunar tidal Love number h2 and find h2=0.0387±0.0025. This result is in agreement with previous estimates from laser altimetry using crossover points of LOLA profiles. The Love numbers k2 and h2 are key constraints on planetary interior models. We further develop and apply a retrieval method based on a simultaneous...

Prospects for measuring Mercury’s tidal Love number h2 with the BepiColombo Laser Altimeter

Thor, Robin N. ; Kallenbach, Reinald ; Christensen, Ulrich R. ; Stark, A. ; Steinbrügge, G. ; Ruscio, A. Di ; Cappuccio, P. ; Iess, L. ; Hussmann, H. ; Oberst, Jürgen (2020-01-15)

Context. The Love number h2 describes the radial tidal displacements of Mercury’s surface and allows constraints to be set on the inner core size when combined with the potential Love number k2. Knowledge of Mercury’s inner core size is fundamental to gaining insights into the planet’s thermal evolution and dynamo working principle. The BepiColombo Laser Altimeter (BELA) is currently cruising t...

Crustal Porosity of Lunar Impact Basins

Wahl, Daniel ; Wieczorek, M. A. ; Wünnemann, K. ; Oberst, Jürgen (2020-04-18)

Lateral variations in bulk density and porosity of the upper lunar highland crust are mapped using a high‐resolution Gravity Recovery and Interior Laboratory (GRAIL) gravity field model and Lunar Reconnaissance Orbiter (LRO) derived topography. With a higher spatial resolution gravity model than previous studies, we focus on individual impact basins with diameters greater than 200 km. The bulk ...

Equipotential Figure of Phobos Suggests Its Late Accretion Near 3.3 Mars Radii

Hu, Xuanyu ; Oberst, Jürgen ; Willner, Konrad (2020-03-30)

The ellipsoidal figure of Phobos has been tentatively interpreted as resulting from accretion in a tidal environment close to its parent planet Mars. The issue is compounded by the rapid tidal decay of the moon's orbit. Consequently, when and where the moon actually formed remains elusive. We determined the gravity equipotential ellipsoid of Phobos during its orbital decay and studied the evolu...

Extracting tides from laser altimetry observations: a global approach

Thor, Robin N. (2020)

Messungen der Planetengezeiten erlauben es, wichtige Rückschlüsse auf die innere Struktur und damit die Entstehung und thermale Entwicklung von Planeten und Monden zu ziehen. Die Gezeiten-Lovezahl h2 beschreibt die radiale Oberflächenverformung durch Gezeiten. Auf dem Planeten Merkur würde eine erfolgreiche Messung von h2 die Existenz eines möglichen festen inneren Kerns beweisen und dabei helf...

Coordinates and maps of the Apollo 17 landing site

Haase, Isabel ; Wählisch, Marita ; Gläser, Philipp ; Oberst, Jürgen ; Robinson, Mark S. (2018-12-07)

We carried out an extensive cartographic analysis of the Apollo 17 landing site and determined and mapped positions of the astronauts, their equipment, and lunar landmarks with accuracies of better than ±1 m in most cases. To determine coordinates in a lunar body‐fixed coordinate frame, we applied least squares (2‐D) network adjustments to angular measurements made in astronaut imagery (Hasselb...

Observations of meteors in the Earth’s atmosphere: Reducing data from dedicated double-station wide-angle cameras

Margonis, Anastasios ; Christou, Apostolos ; Oberst, Jürgen (2018-10-17)

Meteoroids entering the Earth’s atmosphere can be observed as meteors, thereby providing useful information on their formation and hence on their parent bodies. We developed a data reduction software package for double station meteor data from the SPOSH camera, which includes event detection, image geometric and radiometric calibration, radiant and speed estimates, trajectory and orbit determin...

Characterisation of the Perseid meteoroid stream through SPOSH observations between 2010–2016

Margonis, Anastasios ; Christou, Apostolos ; Oberst, Jürgen (2019-06-07)

We have characterised the Perseid meteoroid stream from data acquired in a series of observing campaigns between 2010 and 2016. The data presented in this work were obtained by the Smart Panoramic Optical Sensor Head (SPOSH), an all-sky camera system designed to image faint transient noctilucent phenomena on dark planetary hemispheres. For the data reduction, a sophisticated software package wa...

Re-evaluation of Apollo 17 Lunar Seismic Profiling Experiment data

Heffels, Alexandra ; Knapmeyer, Martin ; Oberst, Jürgen ; Haase, Isabel (2016-12-10)

We re-analyzed Apollo 17 Lunar Seismic Profiling Experiment (LSPE) data to improve our knowledge of the subsurface structure of this landing site. We use new geometrically accurate 3-D positions of the seismic equipment deployed by the astronauts, which were previously derived using high-resolution images by Lunar Reconnaissance Orbiter (LRO) in combination with Apollo astronaut photography. Th...

Exploration of a Halley-type comet and its debris through meteor observations and modelling

Margonis, Anastasios (2019)

This work focuses on the cm-to-mm sized dust particles of the Perseid meteoroid stream, which is well known to originate from the parent comet 109P/Swift-Tuttle. The main objective of the thesis is the characterisation of the stream through dedicated observations of the Perseid meteor shower using the Smart Panoramic Optical Sensor Head (SPOSH) camera system. A series of observing campaigns hav...

Tidal deformation of planets and satellites

Steinbrügge, Gregor (2018)

In this thesis, methods are developed and studied for radar and laser altimetry to measure radial tidal deformations of planets and satellites. The thesis investigates further how the tidal measurement allows constraining the interior structure and rheologic properties of the bodies. A semi-analytical performance model for laser altimetry has been developed to predict probability of false detec...

Determining rotational elements of planetary bodies

Burmeister, Steffi (2017)

Die Rotationselemente eines planetaren Körpers geben seine Orientierung im Raum in Bezug auf den internationalen Himmelsreferenzrahmen (engl. ICRF) an. Sie sind notwendig für die Berechnung von Kontrollpunktnetzen (KPN) und für die Erstellung von z.B. Karten oder Geländemodellen des Körpers. Diese Arbeit beschreibt den Bündelblockausgleich im inertialen Referenzrahmen. Das ist eine Methode, um ...

Vesta CPN 82806

Burmeister, Steffi (2016-11-29)

The ASCII file contains a Control Point Network (CPN) of Vesta, consisting of 82806 points in metric 3D coordinates (m) and the forward intersection error of each coordinate. The CPN was used to create the figures of Vesta in chapter 5 of my dissertation "Determining rotational elements of planetary bodies - Method and implementation of an inertial frame bundle block adjustment"

Phobos CPN 679

Burmeister, Steffi (2016-11-28)

The ASCII file contains a Control Point Network (CPN) of Phobos, consisting of 679 points in metric 3D coordinates (m) and the computed uncertainty of each coordinate. The CPN was used to create the figures of Phobos in chapter 5 of my dissertation "Determining Rotational Elements of Planetary Bodies - Method and Implementation of an Inertial Frame Bundle Block Adjustment".