activity
19972000
collaborators

10 papers

astro-ph2000

Thermodynamical properties of stellar matter: II. Internal energy, temperature and density exponents and specific heats for stellar interiors

W. Stolzmann, T. Bloecker

Starting from the Helmholtz free energy we calculate analytically first- and second-order derivatives, as internal energy and specific heats, for the ideal system and the exchange…

astro-ph2000

The dynamical evolution of the fragmented, bipolar dust shell around the carbon star IRC +10216: Rapid changes of a PPN-like structure?

R. Osterbart, Y. Balega, T. Bloecker +2

We present high-resolution J-, H-, and K-band observations and the first H-K color image of the carbon star IRC +10216. The images were reconstructed from 6m telescope speckle inte…

astro-ph2000

The evolution of helium white dwarfs: III. On the ages of millisecond pulsar systems

D. Schoenberner, T. Driebe, T. Bloecker

We employed recently computed evolutionary white-dwarf models with helium cores, supplemented by heavier models with carbon-oxygen cores, in order to investigate the ages of millis…

astro-ph2000

The dynamical evolution of the dust shell of IRC+10216

R. Osterbart, Y. Balega, T. Bloecker +2

We present high-resolution J-, H-, and K-band observations of the carbon star IRC+10216. The images were reconstructed from 6 m telescope speckle interferograms using the bispectru…

astro-ph1999

On the formation of hydrogen-deficient post-AGB stars

F. Herwig, T. Bloecker, N. Langer +1

We present an evolutionary sequence of a low mass star from the Asymptotic Giant Branch (AGB) through its post-AGB stage, during which its surface chemical composition changes from…

astro-ph1999

Kinematics of the anemic cluster galaxy NGC 4548 - Is stripping still active ?

B. Vollmer, V. Cayatte, A. Boselli +2

We present new HI (20" resolution) and CO observations of NGC 4548, an anemic galaxy in the Virgo cluster. The atomic gas distribution shows a ring structure which is distorted at…