A measurement of the 362 GHz absorption line of Mars atmospheric H2O2

The 362.156 GHz absorption spectrum of H₂O₂ in the Mars atmosphere was observed on September 4 of 2003, employing the James Clerk Maxwell Telescope (JCMT) sub-millimeter facility on Mauna Kea, Hawaii. Radiative transfer analysis of this line absorption yields an average volume mixing ratio of 18±0.4 ppbv within the lower (0-30 km) Mars atmosphere, in general accordance with standard photochemical models (e.g., Nair et al., 1994, Icarus 111, 124-150). Our derived H₂O₂ abundance is roughly three times greater than the upper limit retrieved by Encrenaz et al. (2002, Astron. Astrophys. 396, 1037-1044) from infrared spectroscopy, although part of this discrepancy may result from the different solar longitudes (L_s) of observation. Aphelion-to-perihelion thermal forcing of the global Mars hygropause generates substantial (>200%) increases in HO_x abundances above ∼10 km altitudes between the L_s=112° period of the Encrenaz et al. upper limit measurement and the current L_s=250° period of detection (Clancy and Nair, 1996, J. Geophys. Res. 101, 12785-12590). The observed H₂O₂ line absorption weakens arguments for non-standard homogeneous (Encrenaz et al., 2002, Astron. Astrophys. 396, 1037-1044) or heterogeneous (Krasnopolsky, 2003a, J. Geophys. Res. 108; 2003b, Icarus 165, 315-325) chemistry, which have been advocated partly on the basis of infrared (8 μm) non-detections for Mars H₂O₂. Observation of Mars H₂O₂ also represents the first measurement of a key catalytic specie in a planetary atmosphere other than our own.     

Long-Term Changes of Polar Activity of the Sun

We discuss long-time changes of polar activity of the Sun using the new observational data sets in the optical range during 1872–2001. A study of the secular and cycle variations of the magnetic activity at the high-latitude regions is the main goal that includes polar magnetic field reversals during 1872–2001 and secular changes of the duration of polar activity cycles. The secular increase of the area of polar zones during the minimum activity in the last 120 years and as consequence a decrease of coronal temperature of the Sun in the high-latitude zones during the last 50 years. Correlation between the polar cycles of Caii-K bright points with the Wolf sunspot numbers cycles, W(t), and the 22-year polar magnetic cycles of Caii-K bright points at the high latitudes during 1905–1995 is discussed.     

Prospects for astrometry with the Hubble Space Telescope

The Hubble Space Telescope (HST), a large optical telescope having an aperture of 2.4 meters and a length of 8.8 meters, is being developed by the National Aeronautics and Space Administration. This telescope will be placed into earth orbit by the space shuttle. Astrometric observations with the HST are made using a Fine Guidance Sensor which is capable of measuring the position of one object relative to another with an accuracy of ±0.002 arcseconds. The astrometric user of HST will be provided with an Astrometric Data Reduction Software package (ADRS). The variety of astrometric problems to be investigated with HST is discussed.     

Kinematics of stars in Kovalsky-Kapteyn figures. II

Rostov State Pedagogical Institute; All-Union Scientific Research Institute Gradient. Translated from Astrofizika, Vol. 33, No. 3, pp. 379–393, November–December, 1990.     

宇宙磁场中的中微子

本文讨论了有质量的Dirac粒子在宇宙磁场中的演化。宇宙磁场使空间度规出现各向异性。通过求解Dirac方程,得到了中微子在宇宙磁场中的表观磁矩。