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HST Observations of Abell 2125: Radio Emission and the Butcher-Oemler Effect
Owen, F. N.; Keel, W. C.; Ledlow, M. J. +1 more
The evolution status of HD 104237, ɛ Cha and HD 100546.
Hu, Jingyao; Shen, Chuanjian
Using the new data from Hipparcos and the TD-1 UV data, the authors fix the positions of three objects, HD 104237, HD 100546 and ɛ Cha in the HR diagram and discuss their theoretical evolutionary status.
Erratum: The Ulysses Supplement to the BATSE 3B Catalog of Cosmic Gamma-Ray Bursts
Cline, T.; Hurley, K.; Kouveliotou, C. +5 more
In the paper ``The Ulysses Supplement to the BATSE 3B Catalog of Cosmic Gamma-Ray Bursts'' by K. Hurley, M. S. Briggs, R. M. Kippen, C. Kouveliotou, C. Meegan, G. Fishman, T. Cline, and M. Boer (ApJS, 120, 399 [1999]), the minimum distance between the error circle and the annulus was given incorrectly on page 404. The correct formula isd=θ2
Working Group 2 Report: Energy Input, Heating, and Solar Wind Acceleration in Coronal Holes
Hood, A. W.
Theories and observations of energy input, heating and acceleration mechanisms in the low corona were presented and discussed. The main topics of discussion were large-scale solar wind simulations, theoretical heating mechanisms, observational constraints, confronting theory with observations and observational issues.
A kinematic study of the Galaxy
Liu, Yu; Ma, Wen-zhang
Using the proper motion and parallax data for 1011 O-B stars in the Hipparcos Catalogue we have derived the Oort constants, A = 17.60 ± 0.21 (km/s)/kpc, B = -14.62 ± 0.20 (km/s)/kpc, and a solar velocity V⊙ = 16.7 ± 0.10 km/s in the direction l⊙ = 45.3° ± 2.8°, b⊙ = 21.0° ± 2.3°. For a galactocentric distance of th…
Parametric representation of helioseismic data. I. A method for estimation of mode correlation
Ferrari, A.; Gelly, B.; Schmider, F. -X. +1 more
This paper describes a parametric method aimed at the estimation of correlation in the excitation of solar p modes. Unlike previous work which investigated the correlation in the statistical properties of the mode's power, rather we study the excitation signal itself. In this approach, each mode is represented as a second-order autoregressive proc…
The Onset of Pulsation in Red Giants
Percy, John R.; Guler, Metin
The Hippercos astrometric and photometric database has many applications for undergraduate research projects. As one example, we have investigated the onset of variability in red giants by noting the excess scatter (above and beyond the instrumental scatter) in the Hipparcos photometric measurements of 7600 giants with +1.35 < (V-I) < +1.70.…
Outflow Velocities at the Base of a Polar Coronal Hole During the 1998 Total Eclipse
Vial, J. -C.; Koutchmy, S.; Patsourakos, S. +2 more
Polar coronal holes represent the most convincing site from which the high-speed solar wind originates. Here we report high-accuracy Doppler shifts measured in the O VI (1037.6 Å) line obtained by SUMER on SOHO inside an interplume region within the south polar coronal hole. We infer limits on the outflow velocity and draw hints about the flow geo…
Analysis of Midlatitude Auroral Emissions Observed during the Impact of Comet Shoemaker-Levy 9 with Jupiter
Clarke, John T.; Bauske, Rainer; Combi, Michael R.
During the impact of Comet Shoemaker-Levy 9 fragment K on Jupiter observers detected aurora-like emissions near the impact region as well as in the other hemisphere at approximately magnetic conjugate positions equatorward of auroral latitudes. A number of generation mechanisms were suggested, but investigations of their significance have been ham…
NE VII emission lines in the solar EUV spectrum
Keenan, F. P.; Ryans, R. S. I.; Bell, K. L. +3 more
Recent calculations of electron and proton impact excitation rates in Ne vii are used to calculate theoretical emission line ratios involving both Δn=0 (2-2) and Δn=1 (2-3) transitions in the ∼ 97-895 Å wavelength range. A comparison of these with existing solar observations, obtained by instruments on rocket flights and on the Skylab mission, rev…