Year Books of the Max Planck Society

2018

  • Exploration of dwarf planet Ceres 

    2018 Nathues, Andreas; Christensen, Ulrich R.
    The exploration of the conditions that have prevailed in the early Solar System was the goal of NASA’s Dawn mission [1] for which MPS provided two structurally identical cameras. Dawn initially explored the asteroid Vesta followed by Ceres. The mission phase at Ceres has led to remarkable discoveries. Water ice is present both on the surface and in the interior of Ceres and has modified their mineral composition. In addition, cryomagmatic activity was proven.

2017

  • Solar variability and climate

    2017 Krivova, Natalie; Yeo, Kok Leng; Solanki, Sami K.; Wu, Chi-Ju
    The Sun supplies Earth with light and warmth. It is an unfailing but not fully constant energy source. About 40 years of space-based monitoring of solar irradiance revealed its variations on all time scales that have ever been observed (minutes to decades). The variability on time scales of about a day or longer is driven by the restless solar magnetic field. Knowing how the surface magnetic field changed in the past, it is possible to reconstruct variations in the solar brightness.

2016

  • Sunrise for six days

    2016 Riethmüller, Tino L.; Barthol, Peter; Solanki, Sami K.
    Lifted by a huge helium-filled balloon, the solar observatory Sunrise has already carried out two sixday long flights along the Arctic Circle. While the first flight has provided new insights into the lower atmosphere of the Sun at low magnetic activity, some selected findings of the second flight, carried out at a significantly higher solar activity level, are presented here.

2015

  • Rotation and activity of Sun-like stars

    2015 Nielsen, Martin B.; Gizon, Laurent

    The origin of magnetic spots on stars like the Sun is not understood. Stellar rotation is a key ingredient in models of stellar magnetism. Five Sun-like stars observed by the Kepler space telescope are found for which both the internal rotation rate (using asteroseismology) and the surface rotation rate (using starspots) could be measured. Together these measurements show that the difference between surface and internal rotation in these stars is small, as in the Sun. The upcoming PLATO space mission will allow to apply this analysis to many thousands of sun-like stars.

2014

  • Rosetta and Philae at comet 67P/Churyumov-Gerasimenko

    2014 Boehnhardt, Hermann
    Since summer 2014 Rosetta explores comet 67P/Churyumov-Gerasimenko. In November 2014 the Philae lander landed on the surface of the comet. The first measurements of the scientific instruments allow conclusions on the formation of small bodies in the early phase of solar system formation, on cometary activity and on the importance of comets for the existence of water on Earth.
  • From cold to hot: at the magnetic transition in the solar atmosphere

    2014 Peter, Hardi

    While the Sun appears relatively uniform in visible light, it presents its complex magnetic nature and esthetic beauty in X-rays. Of particular interest in terms of physics is the region governed by the intimate interaction between magnetic field and plasma. This magnetic transition, located a few 1000 km above the solar surface, is the prime topic of the space-based solar observatory IRIS (Interface Region Imaging Spectrograph). Here some results will be reported that present us with a new, more complex view of the atmosphere of the Sun and that pose a variety of new questions.

2013

  • Exploration of the asteroid 4 Vesta

    2013 Nathues, Andreas; Christensen, Ulrich R.

    The exploration of the conditions that have prevailed in the early Solar System is the goal of NASA’s Dawn mission [1], for which MPS provided two cameras (“Framing Cameras“) [2]. The Dawn mission explored the asteroid 4 Vesta from different orbits for a period of one year, and is now approaching asteroid 1 Ceres. The Vesta mission phase led to a series of discoveries as, for example, the proof of an iron core, the widespread occurrence of dark material on the otherwise bright surface, as well as a variety of distinctive surface structures that point to a turbulent past of Vesta.

  • Braiding of magnetic fields on the Sun

    2013 Peter, Hardi

    The outer hot and dynamic atmosphere of the Sun, the corona, is dominated by the magnetic field. Convective motions near the surface are braiding the magnetic field lines that reach into the corona, and by this induce currents which are then dissipated and heat the plasma. Numerical experiments can capture the underlying processes well enough to reproduce the complex observations of the real Sun. The interplay of modern solar observations and numerical models on supercomputers provides the means to get closer to an understanding of the heating, structure, and dynamics of the solar corona.

2012

  • Is convection in the solar interior slower than expected?

    2012 Birch, Aaron; Gizon, Laurent; Hanasoge, Shravan; Langfellner, Jan

    Convection is the main mechanism for transporting energy from the base of the solar convection zone to the surface and is thought to be responsible for maintaining the observed global-scale flows of the Sun. Helioseismology, the use of solar oscillations to study the Sun’s interior, has been applied to observations from the Helioseismic and Magnetic Imager on board the NASA Solar Dynamics Observatory to obtain upper limits on the amplitudes of convective flows. These limits are in conflict with theoretical prediction and demand a rethinking of convection theory.

  • Sources of water in the outer solar system

    2012 Hartogh, Paul
    Its unprecedented sensitivity enabled the Herschel Space Observatory to provide unique solar system observations. Herschel made the first measurement of the hydrogen isotopes D/H in a Jupiter family comet. Unexpectedly the determined value is consistent with the one in the Earth oceans. We conclude that comets are the possible suppliers of the terrestrial water. At the same time Herschel discovered a large water torus, centered on Saturn’s E-ring. It seems to be a medium transporting water originating from cryovolcanic activity of the moon Enceladus into Saturn’s and Titan’s atmospheres.

2011

  • Asteroseismology of a Sun-like planet-hosting star

    2011 Stahn, Thorsten; Gizon, Laurent
    The measurement of stellar oscillations allows us to infer the structure, evolution, and internal rotation of stars. The Sun-like planet-hosting star HD 52265 was observed with the CoRoT space telescope. The analysis of its oscillations allows to estimate the stellar properties mass, radius, and age with high precision. In addition it was possible to infer the stellar internal rotation from its oscillation frequencies.
  • How does a sunspot work?

    2011 Lagg, Andreas; Schüssler, Manfred; Solanki, Sami K.
    The dark sunspots are regions of strong magnetic field at the solar surface. The origin of their characteristic fine structure and the related gas flows remained an unsolved problem for a century. The interplay between observations with highest spatial resolution and realistic computer simulations now led to the resolution of the riddle. The interaction of the magnetic field with the convective motions, which transport energy from the solar interior to the surface, explains the structure and dynamics of sunspots.

2010

  • Exploration of the solar system with Herschel

    2010 Hartogh, Paul
    Herschel, the largest space telescope ever, was launched by an Ariane V rocket on May 14th, 2009 and observes the universe in the far infrared range of the electromagnetic spectrum since. A key project of Herschel is dedicated to the role of water and related chemistry in the solar system. Different classes of comets will be characterized, the cycle of water and its vertical distribution on Mars will be analyzed and the sources of water in the stratospheres of the giant planets and of Saturn’s moon Titan will be explored.

2009

  • Sunrise – a solar observatory in the stratosphere

    2009 Barthol, Peter; Gandorfer, Achim; Schüssler, Manfred; Solanki, Sami K.
    The biggest telescope that ever left the surface of the Earth took off in June 2009 from the European space base ESRANGE near Kiruna (Northern Sweden). Lifted by a helium-filled balloon of 130 meter diameter, the 2.6 ton observatory drifted at a height of 37 km to northern Canada. During the nearly 6 day long flight in the stratosphere, the Sun was observed without interruption, tens of thousands highly resolved images in the ultraviolet light were taken, and the magnetic field at the solar surface was measured with unprecedented precision.

2008

  • Beyond the clouds: News from Venus

    2008 Titov, Dimitri; Markiewicz, Wojciech; Fränz, Markus
    After many years of exploration of planet Venus by sovjet and american spacecraft a large number of questions about history and structure of the planet and its atmosphere remained open. In 2005 the first European mission to planet Venus was launched: Venus Express – with a strong contribution by the MPI for Solar System Research. First analyses of the data received since 2006 show a previously unimagined structuring and dynamics of the cloud layers and allow new conclusions about the evolution of the atmosphere of Venus.

2007

  • Physics of Solar Eruptions

    2007 Inhester, Bernd; Wiegelmann, Thomas
    Since January 2007 the two space craft of NASA's STEREO mission orbit the Sun and provide us for the first time with simultaneously observed images of the Sun from two different viewpoints. The scientists at the MPS have developed analysis tools to generate three-dimensional models of plasma structures in the solar corona and compare them with models of the coronal magnetic field. These investigations aim at a better understanding of energetic eruptions and mass ejections of the solar corona.

2006

  • Helioseismology

    2006 Gizon, Laurent
    Millions of modes of vibration, excited by turbulent convection, enable solar physicists to see inside the Sun. Three dimensional helioseismic techniques offer unique prospects for probing complex magnetohydrodynamical processes and uncovering the mechanism of the solar cycle, while the extension of seismic investigations to distant stars will open a new era of observational stellar research.

2005

  • Planetary Dynamos

    2005 Christensen, Ulrich; Wicht, Johannes; Fränz, Markus
    Nearly all the planets in our solar system possess a magnetic field or had one at some time in the past. The diversity of the planetary fields reflects interesting differences in interior dynamics. Their exploration by space missions or computer simulations is an important tool to provide insight into the otherwise shielded planetary interiors. This short introduction gives an overview of activities at the Max Planck Institute for Solar System Research concentrating mainly on computer models, where considerable progress was achieved during the past years.

2004

  • Measurement of coronal magnetic fields

    2004 Curdt, Werner; Inhester, Bernd; Innes, Davina; Lagg, Andreas; Solanki, Sami K.; Wang, Tongjiang; Wiegelmann, Thomas; Woch, Joachim
    The solar corona harbors gas at temperatures of more than a million degrees. This gas is predominantly trapped on arch-like structures formed by loops of magnetic field. The high temperature and the structure of the coronal gas are attributed to the solar magnetic field. The high degree of order in the corona traces back to the fact that hot gas must follow magnetic field lines. Also magnetic current sheets (“jumps” in the magnetic field) are able to release thermal energy and thus heat the gas. The measurement of coronal magnetic fields is, however, not trivial: the low gas density leads to a weak signature in the spectral lines, i.e. the splitting and polarization caused by the Zeeman-effect. Also, with increasing distance from the solar surface, an effect starts to operate which influences the polarization of the absorbed light. The Max Planck Institute for Solar System Research in Katlenburg-Lindau (MPS) successfully contributed to the solution of this difficult problem of measuring the coronal magnetic field. Two different methods of direct measurement of the magnetic field have been applied: coronal seismology and infrared polarimetry. In addition, based on mathematical models it is possible to infer the coronal magnetic field structure from extrapolations of the reliably determined photospheric magnetic field.

2003

  • SMART-1 - Europe’s Mission to the Moon

    2003 Mall, Urs
    After a limited view of the lunar surface during the years of the Apollo program, remote sensing missions flown during the last ten years have allowed, for the first time, a global overview of the composition of the lunar surface. Lunar science can bring insight into the general understanding of planetary formation theories. After 30 years a new initiative is on the way to resolve the remaining questions in lunar science. Among the currently planned missions, the European SMART-1 (Small Advanced Research Missions) mission will reach the Moon next. As part of the payload a near-infrared spectrometer, named SIR, developed at the Max Planck Institute for Solar System Research (MPS) in Katlenburg-Lindau, will be used to investigate the far side of the Moon, undisturbed from the Earth’s atmosphere, and to participate in the search for water on the Moon.
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