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ISO observations of molecular hydrogen in the DR21 bipolar outflow
Smith, Michael D.; Davis, Christopher J.; Eisloffel, Jochen
We demonstrate that a wide range of molecular hydrogen excitation can be observed in protostellar outflows at wavelengths in excess of 5 mum. Cold H_2 in DR21 is detected through the pure rotational transitions in the ground vibrational level (0-0). Hot H_2 is detected in pure rotational transitions within higher vibrational levels (1-1, 1-2, etc.…
Joint Nançay Radioheliograph and LASCO Observations of Coronal Mass Ejections - I. The 1 July 1996 Event
Llebaria, A.; Michels, D. J.; Schwenn, R. +9 more
The development of a coronal mass ejection on 1 July 1996 has been analyzed by comparing the observations of the LASCO/SOHO coronagraph with those of the Nançay radioheliograph. This comparison brings new insight and very useful diagnosis for the study of CME events. It is shown that the initial instability took place in a small volume located abo…
The separation of the stars in the binary nucleus of the planetary nebula Abell 35
Marsh, T. R.; Lynas-Gray, A. E.; Drew, J. E. +2 more
Using the Planetary Camera on board the Hubble Space Telescope, we have measured the projected separation of the binary components in the nucleus of the planetary nebula Abell 35 to be larger than 0.08 arcsec but less than 0.14 arcsec. The system has been imaged in three filters centred at 2950, 3350 and 5785 Angstroms. The white dwarf primary sta…
Ultraviolet and optical flares on GL 866
O'Donoghue, D.; Butler, C. J.; Drake, S. A. +2 more
We present simultaneous ultraviolet and optical observations of five flares on the very late type M dwarf Gl 866 (dM5.5e). A procedure to estimate the physical parameters of the flaring plasma has been developed using a simplified model of the flare and a comparison of observed and computed Balmer decrements. With this procedure we have determined…
First Astronomical Images Sharpened with Adaptive Optics Using a Sodium Laser Guide Star
McLeod, B. A.; Hooper, E. J.; Angel, J. R. P. +7 more
Adaptive optics with a sodium resonance laser guide star was used at the Multiple Mirror Telescope (MMT) in 1996 April to image the core of the globular cluster M13 (NGC 6205). A 23" field was recorded in the Ks band with image resolution of 0.51", when the uncorrected resolution was 0.72". Global tilt, not sensed by the laser, was meas…
Principal component analysis of two ultraviolet emission-lines in 18 active galactic nuclei
Courvoisier, T. J. -L.; Turler, M.
We apply a principal component analysis (PCA) to the spectra of each of the 18 Seyfert 1-like objects observed more than 15 times by the international ultraviolet explorer (IUE) from 1978 until the end of 1991. PCA allows us to decompose the Lyalpha and Civl\ emission-lines of each object into two components with uncorrelated variations. We find t…
Detection of fine-structure line emission from carbon-rich and oxygen-rich AGB stars by the ISO SWS
Ohnaka, K.; Tsuji, T.; Aoki, W.
We detected five forbidden lines of iron, silicon and sulfur in red giants by the ISO SWS. [FeI] 24mu m emission was detected in two carbon stars, TX Psc and WZ Cas, and [SI] 25.2mu m emission was also detected in TX Psc, while none of these emission lines were detected in an oxygen-rich giant, 30g Her. On the other hand, the [FeII] 26mu m, [SiII]…
Constraints on the Radial Velocity Curve of HDE 245770 = A0535+26
Wang, Z. X.; Gies, D. R.
We present new radial velocity measurements from IUE high-dispersion spectra of HDE 245770, the Be companion of the X-ray transient binary system, A0535+26. We formally derive the semiamplitude of the star's binary motion by fitting the UV and published radial velocity measurements with the other orbital parameters fixed according to the neutron s…
A search for hidden white dwarfs in theROSATEUV survey - II. Discovery of a distant DA+F6/7V binary system in a direction of low-density neutral hydrogen
Barstow, M. A.; Holberg, J. B.; Burleigh, M. R.
The ROSAT Wide Field Camera (WFC) survey of the extreme ultraviolet (EUV) has provided us with evidence for the existence of a previously unidentified sample of hot white dwarfs in unresolved, detached binary systems. These stars are invisible at optical wavelengths due to the close proximity of their much more luminous companions (spectral type K…
Energetic ion populations and periodicities near Jupiter
Balogh, A.; Sarris, E. T.; Anagnostopoulos, G. C. +2 more
The HISCALE experiment, during Ulysses' approach to Jupiter, observed a ~10 hour periodic softening in ion spectrum outside the plasma sheet that (1) is not related to the approach of the plasma sheet, (2) is in phase with the «clock» relativistic electron modulation, and (3) is related to flux increase at low energies (<=200 keV) and flux decr…