8 research outputs found
Peculiarities and variations in the optical spectrum of the post-AGB star V448Lac=IRAS22223+4327
Repeated observations with high spectral resolution acquired in 1998-2008 are
used to study the temporal behavior of the spectral line profiles and velocity
field in the atmosphere and circumstellar envelope of the post-AGB star
V448Lac. Asymmetry of the profiles of the strongest absorption lines with
low-level excitation potentials less 1eV and time variations of these profiles
have been detected, most prominently the profiles of the resonance lines of
BaII, YII, LaII, SiII. The peculiarity of these profiles can be explained using
a superposition of stellar absorption line and shell emission lines. Emission
in the (0;1) 5635A Swan band of the C2 molecule has been detected in the
spectrum of V448Lac for the first time. The core of the Halpha line displays
radial velocity variations with an amplitude ~8 km/s. Radial velocity
variations displayed by weakest metallic lines with lower amplitudes, 1-2 km/s,
may be due to atmospheric pulsations. Differential line shifts, 0 -- 8 km/s,
have been detected on various dates. The position of the molecular spectrum is
stationary in time, indicating a constant expansion velocity of the
circumstellar shell, Vexp=15.2 km/s, as derived from the C2 and NaI lines.Comment: 19 pages, 8 figures, 1 tabl
New Spectroscopic Observations of the Post-AGB Star V354Lac=IRAS22272+5435
The strongest absorption features with the lower-level excitation potentials
eV are found to be split in the high-resolution optical
spectra of the post-AGB star V354 Lac taken in 2007--2008. Main parameters,
T=5650 K, =0.2, =5.0 km/s, and the abundances of 22
chemical elements in the star's atmosphere are found. The overabundance of the
-process chemical elements (Ba, La, Ce, Nd) in the star's atmosphere is
partly due to the splitting of strong lines of the ions of these metals. The
peculiarities of the spectrum in the wavelength interval containing the LiI
6707 \AA{} line can be naturally explained only by taking the
overabundances of the CeII and SmII heavy-metal ions into account. The best
agreement with the synthetic spectrum is achieved assuming (LiI)=2.0,
(CeII)=3.2, and (SmII)=2.7. The velocity field both in the
atmosphere and in the circumstellar envelope of V354 Lac remained stationary
throughout the last 15 years of our observations.Comment: 16 pages, 6 figures, 2 table
The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)
The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics