Publications
Articles:
Refereed Journals:
H. Lammer, C. Kolb, T. Penz, U. V. Amerstorfer, H. K. Biernat, and B. Bodiselitsch, Estimation of the past and present Martian water-ice reservoirs by isotopic constraints on exchange between the atmosphere and the surface, Intern. J. Astrobiology, 2 (3), 195-202, 2003.
In this paper, we present estimations of the water-ice reservoir on Mars based on isotopic constraints. Different loss processes are discussed with respect to their ability to remove water from the Martian atmosphere. We show that about 15 - 30 m of a equivalent global ocean were removed during the last 3.5 Gyr.
T. Penz, N. V. Erkaev, H. K. Biernat, H. Lammer, U. V. Amerstorfer, H. Gunell, E. Kallio, S. Barabash, S. Orsini, A. Milillo, and W. Baumjohann, Ion loss on Mars caused by the Kelvin-Helmholtz instability, Planet. Space Sci., 52, 1157-1167, 2004.
The loss of atmospheric constitutents due to detached plasma clouds caused by the Kelvin-Helmholtz instability is discussed. Because of the velocity difference between the solar wind and the ionospheric plasma, it is likely that the Kelvin-Helmholtz instability occurs at the Martian ionopause. We show that the atmospheric loss due to plasma clouds is in the range of other nonthermal loss processes like ion pickup.
J.-M. Griessmeier, A. Stadelmann, T. Penz, H. Lammer, F. Selsis, I. Ribas, U. Motschmann, H. K. Biernat, and W. W. Weiss, The effect of tidal locking on the magnetospheric and atmospheric evolution of "Hot Jupiters", Astron. Astrophys., 425, 753-762, 2004.
Close-in exoplanets are tidally locked and therefore establish only small magnetospheres. The influences of this effect on the stellar wind interaction and the atmosphere evolution of several exoplanets is discussed.
H. Lammer, I. Ribas, J.-M. Griessmeier, T. Penz, A. Hanslmeier, and H. K. Biernat, A brief history of the solar radiation and particle flux evolution, Hvar Obs. Bullet., 28, 139-155, 2004.
The temporal evolution of the solar radiation and particle flux plays a crucial role for the atmosphere evolution of terrestrial planets. In this article, an overview of the present knowledge of these solar parameters is given.
N. V. Erkaev, T. Penz, H. Lammer, H. I. M. Lichtenegger, H. K. Biernat, P. Wurz, J.-M. Grießmeier, and W. W. Weiss, Plasma and magnetic field parameters in the vicinity of short-periodic giant exoplanets, Astrophys. J. Suppl., 157, 396-401, 2005.
We analyse the plasma and magnetic field parameters at the orbits of close-in giant exoplanets and show that for orbital distances less than ~0.2 AU, no bow shocks are present. Additionally, we calculate ion loss rates and compare them with observations, indicating that most of the escaping particles are neutral hydrogen.
H. Lammer, Yu. N. Kulikov, T. Penz, M. Leitner, H. K. Biernat, and N. V. Erkaev, Stellar-planetary relations: Atmospheric stability as a prerequisite for planetary habitability, Celest. Mech. Dynam. Astron., 92, 273-285, 2005.
The influence of the atmospheric stability on the habitability of exoplanets is discussed. Special emphazise is given to close-in exoplanets orbiting in the habitable zones of M stars. We conclude that it is very unlikely that these close-in exoplanets can establish extended atmospheres and therefore may not harbor surface life as we know it.
T. Penz, H. Lammer, Yu. N. Kulikov, and H. K. Biernat, The influence of the solar particle and radiation environment on Titan's atmosphere evolution, Adv. Space Res., 36, 241-250, 2005.
We discuss the importance of different atmospheric loss processes on titan during its origin. Because of the strong solar wind of the young Sun, the magnetosphere of Saturn was significantly compressed and therefore Titan was directly exposed to the solar wind, leading to enhanced atmospheric loss by ion pick-up and sputtering. However, the achieved loss rates cannot account for the observed 15N/14N isotope ratio in Titan's atmosphere. Therefore, we suggest that large loss rates occur during the early evolution of Titan due to hydrodynamic loss because of the high XUV flux of the young Sun.
T. Penz, I. L. Arshukova, N. Terada, H. Shinagawa, N. V. Erkaev, H. K. Biernat, and H. Lammer, A comparison of magnetohydrodynamic instabilities at the Martian ionopause, Adv. Space Res., 36, 2049-2056, 2005.
The occurrence of different magnetohydrodynamic instabilities, namely the Kelvin-Helmholtz instability, the Kelvin-Helmholtz instability in Hall-MHD, the Rayleigh-Taylor instability, and the interchange instability, are discussed. Additionally, we show that a strong curvature of the ionopause due to localized remnant crustal magnetism may give very high growth rates for the interchange instability.
V. S. Semenov, T. Penz, V. V. Ivanova, V. A. Sergeev, H. K. Biernat, R. Nakamura, M. F. Heyn, I. V. Kubyshkin, and I. B. Ivanov, Reconstruction of the reconnection rate from Cluster measurements: First results, J. Geophys. Res., 110, A11217, doi:10.1029/2005JA011181, 2005.
First results of a reconstruction method for the reconnection rate in an incompressible plasma are presented. It is based on a time-dependent Petschek-type model of magnetic reconnection, which allows to represent the disturbances in the ambient plasma and magnetic field in the form of convolution integrals. The inverse problem is solved by using Tikhonov regularization, allowing to reconstruct the reconnection rate. Additionally, we give a rough estimation of the reconnection site. The model is applied to a series of nightside flux transfer events, which were observed by the Cluster satellites on September 8th, 2002, in the magnetotail. The method gives a reconnection rate of about 2 mV/m and a reconnection site of about -29 Re in the tail.
T. Penz, V. S. Semenov, V. V. Ivanova, H. K. Biernat, V. A. Sergeev, R. Nakamura, I. V. Kubyshkin, I. B. Ivanov, and M. F. Heyn, A reconstruction method for the reconnection rate applied to Cluster magnetotail measurements, Adv. Space Res., in press.
T. Penz, V. S. Semenov, V. V. Ivanova, M. F. Heyn, I. B. Ivanov, and H. K. Biernat, Green's function of compressible Petschek-type magnetic reconnection, Phys. Plasmas, accepted.
H. K. Biernat, V. S. Semenov, T. Penz, C. Miklenic, A. Veronig, A. Hanslmeier, B. Vrsnak, M. F. Heyn, I. B. Ivanov, V. V. Ivanova, S. A. Kiehas, and D. Langmayr, Theoretical and observational features of magnetic reconnection, Cent. Europ. Astrophys. Bullet., in press.
Proceedings, Books:
H. K. Biernat, N. V. Erkaev, T. Penz, H. Lammer, S. C. Manrubia, F. Selsis, D. F. Vogl, and S. Mühlbachler, Magnetic field reversals on Earth: Possible implications for the biosphere, Proceedings of the Second European Workshop on Exo/Astrobiology, ESA-Special Papers 518, 443, 2003.
H. Lammer, F. Selsis, I. Ribas, H. I. M. Lichtenegger, T. Penz, E. F. Guinan, S. J. Bauer, and W. W. Weiss, Migrating Neptune-class bodies as a source for large terrestrial planets, Proceedings "Towards other Earths: DARWIN/TPF and the search for extrasolar terrestrial planets", ESA-Special Papers 539, 491, 2003.
C. Kolb, R. Abart, E. Wappis, T. Penz, E.K. Jessberger, and H. Lammer, The meteoritic component on the surface of Mars: Implications for organic and inorganic geochemistry, Meteoritics & Planetary Science, 38, A15, 2003.
C. Kolb, R. Abart, E. Wappis, T. Penz, H. Lammer, and E. K. Jessberger, The meteoritic input on Mars - Influence on organic geochemistry, Proceedings of the Third European Workshop on Exo/Astrobiology, ESA-Special Papers 545, 225, 2004.
U. V. Amerstorfer, H. Lammer, T. Tokano, F. Selsis, C. Kolb, A. Bércés, G. Kovács, M. R. Patel, C. S. Cockell, Gy. Rontó, T. Penz, N. V. Erkaev, and H. K. Biernat, Evolution of the Martian surface pressure: Implications for the planetary surface environment, Proceedings of the Third European Workshop on Exo/Astrobiology, ESA-Special Papers 545, 165, 2004.
T. Penz, V. S. Semenov, V. V. Ivanova, I. B. Ivanov, V. A. Sergeev, R. Nakamura, M. F. Heyn, I. V. Kubyshkin, and H. K. Biernat, Application of a reconstruction method for the reconnection rate applied to Cluster data from the Earth magnetotail, Proceedings of the 5th International Conference on Problems of Geocosmos, St. Petersburg, Russia, p. 109, 2004.
I. B. Ivanov, V. S. Semenov, M. F. Heyn, and T. Penz, Patterns of MHD perturbations driven by 3-D time-dependent magnetic reconnection in a compressible plasma, Proceedings of the 5th International Conference on Problems of Geocosmos, St. Petersburg, Russia, p. 66, 2004.
T. Penz, H. Lammer, N. V. Erkaev, J.-M. Grießmeier, D. F. Vogl, H. K. Biernat, A. Hanslmeier, and W. W. Weiss, Plasma and magnetic field parameters at bow shocks of short period extrasolar gas giants, Proceedings of the Workshop on Auroral Phenomena, Apatity, Russia, p. 39, 2004.
V. S. Semenov, T. Penz, M. F. Heyn, I. B. Ivanov, I. V. Kubyshkin, H. K. Biernat, and V. V. Ivanova, Reconstruction of the reconnection rate from perturbations in the ambient magnetic field, Proceedings of the Workshop on Auroral Phenomena, Apatity, Russia, p. 47, 2004.
U. V. Amerstorfer, T. Penz, N. V. Erkaev, H. K. Biernat, and H. Lammer, Instability induced momentum transfer at the Martian ionopause, Proceedings of the Workshop on Auroral Phenomena, Apatity, Russia, p. 61, 2004.
T. Penz, H. Lammer, C. Kolb, and H. K. Biernat, Geochemical and astrobiological constraints on fast evolution of complex life on exoplanets, in PanGeo 2004 - Ber. Inst. Erdwiss., B. Hubmann and W. Piller (Eds.), Bd. 9, p. 319, 2004
H. Lammer, F. Selsis, T. Penz, U. V. Amerstorfer, H. I. M. Lichtenegger, C. Kolb, and I. Ribas, Atmospheric evolution and the history of water on Mars, in Water on Mars and Life, T. Tokano (Ed.), Springer-Verlag, Heidelberg, Germany, p. 25, 2005.
H. K. Biernat, N. V. Erkaev, I. L. Arshukova, C. J. Farrugia, H. Lammer, T. Penz, U. V. Amerstorfer, D. F. Vogl, T. L. Zhang, K. Schwingenschuh, R. Nakamura, W. Baumjohann, H. Gunell, M. Holmström, E. Kallio, S. Orsini, A. Milillo, K. Gether, and M. Leitner, Aspects of solar wind interaction with Venus, in Solar-planetary relations, H. K. Biernat, H. Lammer, D. F. Vogl, and S. Mühlbachler (Eds.), Research Signpost, Trivandrum, India, p. 153, 2005.
H. Lammer, H. I. M. Lichtenegger, T. Penz, U. V. Amerstorfer, C. Kolb and H. K. Biernat, Solar wind erosion of the Martian and Venusian atmospheres, in Solar-planetary relations, H. K. Biernat, H. Lammer, D. F. Vogl, and S. Mühlbachler (Eds.), Research Signpost, Trivandrum, India, p. 209, 2005.
V. S. Semenov, T. Penz, M. F. Heyn, I. B. Ivanov, I. V. Kubyshkin, H. K. Biernat, and V. V. Ivanova, Reconstruction of the reconnection rate from magnetic field disturbances in an incompressible plasma, in Solar-planetary relations, H. K. Biernat, H. Lammer, D. F. Vogl, and S. Mühlbachler (Eds.), Research Signpost, Trivandrum, India, p. 261, 2005.
H. K. Biernat, N. V. Erkaev, I. L. Arshukova, T. Penz, and U. V. Amerstorfer, On magnetohydrodnamic instabilities on Venus, in Festshrift on the occasion of the 75th birthday of Prof. Siegfried Bauer, H. O. Rucker and R. Leitinger (Eds.), p.49, 2005.
T. Penz, H. K. Biernat, W. Piller, and H. Lammer, Constraints for the evolution of habitable planets: Implications for the search of life in the Universe, in Festshrift on the occasion of the 75th birthday of Prof. Siegfried Bauer, H. O. Rucker and R. Leitinger (Eds.), p.263, 2005.
T. Penz, V. V. Ivanova, V. S. Semenov, I. B. Ivanov, V. A. Sergeev, R. Nakamura, H. K Biernat, I. V. Kubyshkin, and M. F. Heyn, Reconstruction of nightside flux transfer events using Cluster data, Proceedings of the Workshop on Auroral Phenomena, Apatity, Russia, p. 44, 2005.
S. A. Kiehas, V. S. Semenov, I. V. Kubyshkin, T. Penz, H. K. Biernat, D. Langmayr, A. Runov, and R. Nakamura, Magnetic field and shock behavior in the time-dependent Petschek
reconnection model, Proceedings of the Workshop on Auroral Phenomena, Apatity, Russia, p. 17, 2005.
T. Penz, V. V. Ivanova, V. S. Semenov, R. Nakamura, M. F. Heyn, I. B. Ivanov, I. V. Kubyshkin, and H. K. Biernat, Magnetic reconnection in the Earth's magnetotail: Reconstruction method and data analysis, in Progress in Space Physics Science, Nova Science Publisher, Hauppage, NY, USA, in press.
H. Lammer, T. Penz, N. K. Belisheva, Yu. N. Kulikov, and H. K. Biernat, Prerequisites for the evolution of life on exoplanets, in Cellular Origins, Life in Extreme Habitats, and Astrobiology, J. Seckbach (Ed.), Springer-Verlag, Heidelberg-Berlin, Germany, in press.
Diploma theses:
T. Penz, Remote sensing of flux transfer events based on the theory of ill-posed inverse problems, Graz, 2002.
T. Penz, Magnetohydrodynamic instabilities at the ionopauses of Venus and Mars and their influence on atmospheric ion loss, Graz, 2003.
T. Penz, Habitable planets in the Universe: An interdisciplinary approach regarding the origin and distribution of life, Graz, 2005.
Internal Reports:
T. Penz, H. K. Biernat, V. S. Semenov, N. V. Erkaev, I. V. Kubyshkin, I. V. Alexeev, N. N. Volkonskaya, and S. Mühlbachler, A theoretical model for the reconstruction of reconnection structures from satellite measurements, Veröffentl. d. ÖAW, IWF 146, 2003.
T. Penz, H. K. Biernat, H. Lammer, N. V. Erkaev, I. L. Arshukova, and U. V. Amerstorfer, Planetary ion loss due to MHD instabilities, Veröffentl. d. ÖAW, IWF 149, 2003.
U. V. Amerstorfer, H. K. Biernat, H. Lammer, N. V. Erkaev, T. Penz, and R. Kleindl, The solar wind interaction with Venus and Mars with regard to the atmospheric evolution, Veröffentl. der ÖAW, IWF 154, Graz, 2004.
S. A. Kiehas, V. S. Semenov, I. V. Kubyshkin, A. Runov, T. Penz, H. K. Biernat, R. Nakamura, and D. Langmayr, Time-dependent Petschek-type magnetic reconnection for a moving X-line with applications to Earth's magnetosphere, Veröffentl. der ÖAW, IWF 162, Graz, 2005.
T. Penz, H. K. Biernat, W. Piller, and H. Lammer, On the evolution of habitable planets, Veröffentl. der ÖAW, IWF 165, Graz, 2005.