The position of ET And in the Hertzsprung-Russell diagram

The interstellar lines of Call (K) and NaI (D) are the main means used to estimate the distance of the Ap star ET And to derive its position in the HRD, because the classical methods for the determination of M are affected by some restrictions. By these means the star lies distinctly above the main sequence. The post-main sequence evolutionary stage suggests to assume that pulsations are the reason for the observed short-time spectroscopic and photemetric variations. Possibly, the 1.61-day period is also caused by pulsations.     

A Programme to derive from terrestrial observations the rotation of the HIPPARCOS system with reference to the inertial system

The connection of the HIPPARCOS system with a quasi-inertial system can be reached by transforming the HIPPARCOS proper motions to absolute proper motions. The Tautenburg Schmidt telescope provides such proper motions with respect to extragalactic objects with an accuracy of 0″.6/100a. The telescope as well as the measuring and reduction technique are described. The accuracy of the link of the HIPPARCOS system to extragalactic objects depends on the accuracy of the transformation matrix which represents the time-depending part of the rotation matrix to be applied to the whole HIPPARCOS catalogue. To obtain a reliable estimate for the error of transformation we used the error propagation law. An accuracy of 0″.12/100a for the transformation can be achieved with six Tautenburg fields.     

Magnetic Field Observations of the Ap Star γ Equ

Further investigations of the Ap star γ Equ (SCHOLZ , 1975) showed that a very slow variation of the longitudinal magnetic field exists, with a change of sign in the years 1970/1971. In three spectrograms obtained near of the crossover points of the longitudinal magnetic field hints are given at the presence of a transversal magnetic field of about 3500 Gauß. The radial velocity measurements show no definitive variations.     

Hydrogeological investigation of Antalya basin concerning the future domestic water needs of Antalya City (Turkey)

A hydrogeological study has been carried out in Antalya travertine basin for the future domestic water supply of Antalya. Geological formations that could be used as an aquifer have been identified, and a hydrogeological map has been prepared. Water-quality analyses show that groundwater has been and is being contaminated by sewage discharge, industrial works, and other activities that create an ever-expending impact to the only available aquifer. Something should be done immediately to protect the aquifer from additional degradation. Received: 28 April 1998 · Accepted: 18 August 1998     

Membership of faint stars in the globular cluster M3

A proper motion study from Tautenburg Schmidt plates is presented for the globular cluster M3 and its vicinity. The plates were scanned with the Automated Photographic Measuring (APM) system in Cambridge (UK). A photographic B,V photometry and star counts on the deepest plates were carried out. With a limiting magnitude of about B = 21.4 proper motions with an accuracy from 2 to 3 mas/yr have been obtained for stars with B 19. The proper motions were determined using a stepwise regression method with 3rd order polynomials in the plate-to-plate solutions with about 2000 reference galaxies. The results which were corrected for systematic errors dependent on position and magnitude of the stars were used for the determination of membership probabilities. We also looked for possible internal motions of M3.     

Untersuchungen der magnetischen Ap-Sterne 53 Cam und γ Equ

The determination of the radial velocity and the effective magnetic field strength for the peculiar A-type stars 53 Cam and γ Equ lad to the following results 53 Cam: The radial velocity shows a dependence on the excitation, resp. ionization potential in the way that evidently lines with higher excitation potential have higher radial velocity. We cannot explain this result with the rotator model without an essential modification of that. The amount and the time variation of the effective magnetic field agrees only approximately with that determined by BABCOCK. A secular variation may be indicated, but needs further confirmation. The effective magnetic field strength determined from the SiII-line λ = 4130.884 Å shows an essential smaller value than that by the other lines. The investigation of γ Equ yielded the following results: The best way to represent both the radial velocity and the effective magnetic field strength is a period of 1786 days given by STEINITZ and PYPER. We did not find a difference of the radial velocities derived from different lines and no line intensity variations. However, there seems to be observational evidence that short and obvious accidental variations of the radial velocity and effective magnetic field exist.     

Photometrische und spektrographische Beobachtungen des magnetischen Sterns HD 98088

For the spectroscopic binary HD 98088 with an Ap component UBV photoelectric lightcurves and four Zeeman-spectrograms were obtained in 1971. The results for the radial velocities and effective magnetic fields confirm the phase relations. The lightcurve in U is shifted in phase about 90° relative to the curves in B and U. The U minimum is in coincidence with the positive maximum of the effective magnetic field. The absence of eclipses was confirmed.     

Evaluation of a Finite-Element Sea-Ice Ocean Model (FESOM) set-up to study the interannual to decadal variability in the deep-water formation rates

The characteristics of a global set-up of the Finite-Element Sea-Ice Ocean Model under forcing of the period 1958–2004 are presented. The model set-up is designed to study the variability in the deep-water mass formation areas and was therefore regionally better resolved in the deep-water formation areas in the Labrador Sea, Greenland Sea, Weddell Sea and Ross Sea. The sea-ice model reproduces realistic sea-ice distributions and variabilities in the sea-ice extent of both hemispheres as well as sea-ice transport that compares well with observational data. Based on a comparison between model and ocean weather ship data in the North Atlantic, we observe that the vertical structure is well captured in areas with a high resolution. In our model set-up, we are able to simulate decadal ocean variability including several salinity anomaly events and corresponding fingerprint in the vertical hydrography. The ocean state of the model set-up features pronounced variability in the Atlantic Meridional Overturning Circulation as well as the associated mixed layer depth pattern in the North Atlantic deep-water formation areas.     

Optical spectroscopy of high proper motion stars: new M dwarfs within 10 pc and the closest pair of subdwarfs

We present spectra of 59 nearby star candidates, M dwarfs and white dwarfs, previously identified using high proper motion catalogues and the DENIS database. We review the existing spectral classification schemes and spectroscopic parallax calibrations in the near-infrared J band and derive spectral types and distances of the nearby candidates. Forty-two stars have spectroscopic distances smaller than 25 pc, three of them being white dwarfs. Two targets lie within 10 pc, one M8 star at 10.0 pc (APMPM J0103−3738), and one M4 star at 8.3 pc (L 225−57). One star, LHS 73, is found to be among the few subdwarfs lying within 20 pc. Furthermore, together with LHS 72, it probably belongs to the closest pair of subdwarfs we know.