Suzaku observations of charge exchange emission from solar system objects

Recent results of charge exchange emission from solar system objects observed with the Japanese Suzaku satellite are reviewed. Suzaku is of great importance to investigate diffuse X‐ray emission like the charge exchange from planetary exospheres and comets. The Suzaku studies of Earth's exosphere, Martian exosphere, Jupiter's aurorae, and comets are overviewed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectroscopic investigation of objects of the Second Byurakan Survey. Stellar objects. V

Byurakan Astrophysical Observatory; Special Astrophysical Observatory. Translated from Astrofizika, Vol. 34, No. 3, pp. 315–325, May–June, 1991.     

Spectroscopic observations of V1118 Ori in 1989

The spectra of the star V1118 Ori obtained during the fuor-like outburst in 1989 are typical of classical T Tau stars. The Balmer emission lines of hydrogen and Call are the most prominent lines in the spectrum. A short-wavelength absorption component of the H line shifted –500 km/sec from the H peak was observed in the spectrum of December 19, 1989, which indicates an strong outflow of material from the star. The rate of fuor-like outbursts for V1118 Ori during its active period has been once every three years on the average. There is some similarity between slow out bursts and the outbursts of EXors (subfuors).Translated fromAstrofizika, Vol. 39, No. 3, pp. 365–374, July–September, 1996.     

Spectroscopic observations of red dwarfs. III. Observations of red stars in the solar neighborhood

This list is based on 20 stars in the solar neighborhood for which there are 52 spectra. Twelve of them are known as UV Ceti flare stars. The others behave like flare stars, but are not known to be such. Among the 20 there are many binary and triple flare stars. They all belong to the disk population of the Galaxy. Red dwarfs comprise one of the numerous populations of the system. Flare stars either continue to flare or have ceased flare activity. Three diagrams are given that show satisfactory agreement with the expected ones. A cluster analysis is carried out, which is in agreement with the original proposition and confirms the foregoing.     

Spectroscopic and photometric observations of unidentified ultraviolet variable objects in the GUVV-2 Catalog

An NUV-optical diagram composed from sources from the second Galaxy Evolution Explorer(GALEX) Ultraviolet Variability(GUVV-2) Catalog provides us with a method to tentatively classify the unknown GUVV-2 sources by their NUV-optical magnitudes.For the purpose of testing the correctness and generality of the method,we carry out a program on the spectroscopic observations of the unidentified GUVV-2 sources.The spectroscopic identification of these 37 sources are 19 type-A to-F stars,10 type-G to-K stars and 7 ...     

Development of ephemeris support in observations of distant radio sources and solar system objects at RATAN-600 radio telescope

New elements of the algorithmic and software bases of the ephemeris support for the RATAN-600 radio telescope observations of distant radio sources and objects of the Solar system are briefly described.     

Spectroscopic investigations of objects of the Second Byurakan Survey. Stellar objects. IV

Byurakan Astrophysical Observatory; Special Astrophysical Observatory, USSR Academy of Sciences. Translated from Astrofizika, Vol. 34, No. 1, pp. 5–12, January–February, 1991.     

Voyager U.V. spectrometer observations of He 584 Å dayglow at Jupiter

The intensity of Jupiter's He 584 Å airglow has been measured by the Voyager U.V. spectrometers. The disc-averaged brightness is about 4 Rs and limb darkening is present. The intensity probably varies with longitude, the variation being out of phase with the H Lyman-α intensity bulge. Modelling of resonance scattering of the solar He 584 Å line by Jupiter's atmosphere has shown that the hydrogen and helium emissions can be explained about equally well by at least two self-consistent scenarios involving the structure (temperature and eddy diffusion coefficient) and excitation of the atmosphere. All our evidence points to a dramatic change of conditions in the Jovian atmosphere in the time between Pioneer and Voyager encounters.     

Astrometric baseline observations of solar system bodies

The use of ground-based and space baseline observations of Solar System bodies is considered. Baseline observations allow one to determine the distance to observed objects and (in some cases) the parameters of their orbital motion. Certain results of baseline observations of near-Earth asteroids and the results of model analysis of spacecraft observations are presented.     

Evidence for objects of lunar mass in the early solar system

The problem of the accumulation of the Moon is discussed on the assumption that the Moon is a captured object. If it is such, it is highly improbable that it is the only object of this kind present in the early solar system. Evidence indicating that other massive objects were present at that time is presented. Also, it is pointed out that interior of the Moon must contain normal solar proportions of the elements of intermediate volatility in the lunar interior, if the Moon accumulated in a gas sphere.     

Polarimetric observations of blue FBS stellar objects. II

Translated fromAstrofizika, Vol. 36, No. 2 pp. 203–209, April–June 1993.     

The geometric calibration of the Planck satellite using solar system objects

The geometric calibration of the Planck satellite using the planetary transits is investigated, together with the reconstruction of any offsets from the nominal layout of the focal plane. The methods presented here may be applied to a single focal plane transit of a planet, to find the values of the geometric-calibration parameters at the epoch of the transit or all the transits over the course of the mission. The pointing requirements are easily met, with the pointing reconstruction being dominated by the errors due to the star tracker.     

RATAN-600 radio telescope in the 24th solar activity cycle. IV. Information system for RATAN-600 solar observations

The development of observational equipment and software for processing and efficient representation of spectral and polarization solar microwave observations on the RATAN-600 contributes to obtaining new information about the parameters of plasma at the chromospheric and coronal levels. Current status of information system for RATAN-600 solar observations is described, which is devoted to automatically capturing, storing, transmitting and processing the data and near-real-time publishing them on the Internet. The user web interface for interactive search, visualization, and on-line analysis of the data is available at .     

Photometric observations of the binary system V350 Lacertae

DifferentialUBV observations of the small amplitude (0.12 mag inV) single-lined active binary V350 Lac are presented. It was observed that the light minima occur in conjunction time. A shift of the light curve (0.05 in orbital phase) towards lower phases could be due to a small error in the light elements. The primary minimum is about 0.04 mag deeper than the secondary. It was shown that different depths of two light minima are not produced by the reflection effect but due primarily to gravity darkening on the tidally elongated and synchronously rotating visible component. An O'Connel effect observed as the brighter primary maximum could be an indication of starspot activity or gas streaming between the components.     

Ultraviolet observations of small bodies in the solar system by OAO-2

Broadband filter photometry from 2100 to 4300 Å has been obtained by OAO-2 for the following objects: The Galilean satellites; Titan; the rings of Saturn; and three asteroids. Agreement with independent ground-based photometry in the region of overlap is good. The previously known decrease in reflectivity from visual to ground-based ultraviolet wavelengths continues to 2590 Å for all these objects. Europa's reflectivity continues to decline towards 2110 Å, and the rings' reflectivity levels off from 2590 to 2110 Å. Other targets were too faint at 2110 Å to be measured reliably by OAO-2.The low ultraviolet albedo of Titan has important implications for that planet's atmospheric structure (Caldwell, Larach, and Danielson, 1973; Danielson, Caldwell, and Larach, 1973; Caldwell, 1974b). The ultraviolet reflectivity of Saturn's rings is suggestive of a two-component system, one being pure H₂O particles. The ultraviolet albedos of the Galilean satellites are consistent with existing upper limits for atmospheric abundances, but require either that former estimates of the fractional coverage of H₂O frost are too high, an unlikely circumstance, or that the frost has been darkened by some external agent in the space environment.     

Preparation for the solar system observations with Herschel: Simulation of Jupiter observations with PACS

Observations of the water inventory as well as other chemically important species on Jupiter will be performed in the frame of the guaranteed time key project of the Herschel Space Observatory entitled “Water and related chemistry in the Solar system”. Among other onboard instruments, PACS (Photodetector Array Camera and Spectrometer) will provide new data of the spectral atlas in a wide region covering the far-infrared and submillimetre domains, with an improved spectral resolution and a higher sensitivity compared to previous observations carried out by Cassini/CIRS (Composite InfraRed Spectrometer) and by ISO (Infrared Space Observatory).In order to optimise the observational plan and to prepare for the data analysis, we have simulated the expected spectra of PACS Jupiter observations. Our simulation shows that PACS will promisingly detect several H₂O emission lines. As PACS is capable of spatially resolving the Jovian disk, we will be able to discern the external oxygen sources in the giant planets by exploring the horizontal distribution of water. In addition to H₂O lines, some absorption lines due to tropospheric CH₄, HD, PH₃ and NH₃ lines will be observed with PACS. Furthermore, owing to the high sensitivity of the instrument, the current upper limit on the abundance of hydrogen halides such as HCl will be also improved.     

Comparative studies of meteoroid-planet interaction in the inner solar system

We review the current state of studies in planet–meteoroid interactions, a relatively new discipline in planetary science. Recent observations of phenomena such as meteor trails in the atmosphere of Mars and impact flashes on the Moon have prompted new theoretical work in the field. However, our ability to test these new models and advance our understanding of the processes involved is being inhibited by the lack of systematic long-term observations with instruments dedicated to the task. Here we consider the different types of meteoroid effects on a planetary environment. The current state of knowledge leads us to expect signatures detectable by existing instrumentation, either serendipitously or, in a more targeted fashion, by employing such apparatus in innovative ways and making use of already available model predictions. These will result in near-term advances in the field, to be used towards incorporating meteoroid-effect-detecting capabilities explicitly into future planetary instrumentation or building dedicated instruments.     

Spectroscopic observations of red dwarfs I. Flare stars in the Pleiades

Byurakan Astrophysical Observatory. Translated from Astrofizika, Vol. 33, No. 1, pp. 5–20, July–August, 1990.