77 research outputs found
Asteroseismology of the {\it Kepler} target KIC\,9204718
The high precision data obtained by the {\it Kepler} satellite allows us to
detect hybrid type pulsator candidates more accurately than the data obtained
by ground-based observations. In this study, we present preliminary results on
the new analysis of the {\it Kepler} light curve and high resolution
spectroscopic observations of pulsating Am star KIC\,9204718. Our tentative
analysis therefore show that the star has hybrid pulsational characteristics.Comment: 'Proceedings of Wide Field variability surveys : a 21 st Century 22nd
Los Alamos Stellar Pulsation Conference San Pedro De Atacama ,Chile Nov
28-Dec 2, 2016' to be published by the EPJ Web of Conference
Selectivity of 40 mm square and 50 mm diamond mesh codends for five species in the Eastern Mediterranean demersal trawl fishery
The aim of this study was to determine the selectivity of 40 mm square (40S) and 50 mm diamond (50D) mesh codend for five species, red mullet (Mullus barbatus), annular sea bream (Diplodus annularis), common Pandora (Pagellus erythrinus), axillary sea bream (Pagellus acarne) and blotched picarel (Spicara maena) in the Eastern Mediterranean. Selectivity data were collected by the covered codend method and analyzed. Mean selection curves were analyzed and compared using the between haul variations model for red mullet and annular sea bream. Pooled data were used for common Pandora, axillary sea bream and blotched picarel. In total, 22 valid hauls, 10 with 40S and 12 with 50D codends were carried out. The 50% retention lengths (L50) of 40S and 50D codend were found as 14.5 and 15.3 cm for red mullet, 9.5 and 11.3 cm for annular sea bream, 13.1 and 15.0 cm for common Pandora, 14.4 and 15.3 cm for axillary sea bream, 14.5 and 17.2 cm for blotched picarel, respectively. This study showed that codends with 40S and 50D L50 results improve the selectivity when considering commercially used 40 mm nominal diamond mesh codend in Turkish seas for given species. However, in multi-species, it seems likely that a separation of species system would potentially be of more value than size-selective systems. Therefore, different selective techniques such as grid and separation panel and behaviour of the species against the gear need to be investigated.Key words: Codend selectivity, 40 mm square mesh, 50 mm diamond mesh, Eastern Mediterranean, demersal trawl
Marginally low mass ratio close binary system V1191 Cyg
In this study, we present photometric and spectroscopic variations of the
extremely small mass ratio () late-type contact binary system
\astrobj{V1191 Cyg}. The parameters for the hot and cooler companions have been
determined as = 0.13 (1) , = 1.29 (8)
, = 0.52 (15) , = 1.31 (18)
, = 0.46 (25) , = 2.71 (80)
, the separation of the components is = 2.20(8) and
the distance of the system is estimated as 278(31) pc. Analyses of the times of
minima indicates a period increase of
days/yr that reveals a very high mass transfer rate of
/yr from the less massive
component to the more massive one. New observations show that the depths of the
minima of the light curve have been interchanged.Comment: Accepted for publication in New Astronomy, 16 pages, 2 figures, 4
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Absolute properties of the binary system BB pegasi
We present ground-based photometry of the low-temperature contact binary BB Peg. We collected all the times of mid-eclipse available in the literature and combined them with those obtained in this study. Analyses of the data indicate a period increase of (3.0 ± 0.1) × 10-8 days yr -1. This period increase of BB Peg can be interpreted in terms of the mass transfer 2.4 × 10-8 M⊙ yr-1 from the less massive to the more massive component. The physical parameters have been determined as Mc = 1.42M⊙, Mh = 0.53 M⊙, Rc = 1.29 R⊙, Rh, = 0.83 R⊙, Lc = 1.86 L⊙, and L h = 0.94 L⊙ through simultaneous solutions of light and of the radial velocity curves. The orbital parameters of the third body, which orbits the contact system in an eccentric orbit, were obtained from the period variation analysis. The system is compared to the similar binaries in the Hertzsprung-Russell and mass-radius diagrams.Ege University Research Fund and TÜBİTAK National Observator
Close Binary System GO Cyg
In this study, we present long term photometric variations of the close
binary system \astrobj{GO Cyg}. Modelling of the system shows that the primary
is filling Roche lobe and the secondary of the system is almost filling its
Roche lobe. The physical parameters of the system are , , , , , , and . Our results show that \astrobj{GO
Cyg} is the most massive system near contact binary (NCB). Analysis of times of
the minima shows a sinusoidal variation with a period of years due
to a third body whose mass is less than 2.3. Finally a period
variation rate of d/yr has been determined using all
available light curves.Comment: Accepted for publication in New Astronomy, 18 pages, 4 figures, 7
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