Recent UBVR Photometry of Symbiotic Stars

2003 ◽  
Vol 12 (4) ◽  
Author(s):  
A. Skopal ◽  
M. Vaňko ◽  
T. Pribulla ◽  
D. Chochol
Keyword(s):  
Light Curve ◽  
Active Phase ◽  
Symbiotic Stars ◽  
Short Term ◽  
Quiescent Phase ◽  
Photometric Observations ◽  
Made In

AbstractWe present recent photometric observations of Z And, BF Cyg, and AX Per made in the standard Johnson UBVR system. The main characteristics of their light behavior can be summarized as follows: Z And: our observations cover the recent active phase, from its maximum in 2000 December to the latest measurements (2003 September). BF Cyg: the minimum of the recent wave in the star’s brightness was the deepest ever observed; in 2003 February a short-term flare developed in the light curve. AX Per: from 1995 October the light curve displays signatures of a quiescent phase of the star; in 2003 May a 0.5 mag flare was detected.

scholarly journals A Spectroscopic and Photometric Study of the Shell Star EW Lac

2000 ◽  
Vol 175 ◽  
pp. 554-557
Author(s):  
Huilai Cao ◽  
Zhongwei Li ◽  
Lin Huang ◽  
Yulian Guo
Keyword(s):  
Active Phase ◽  
Anomalous Behavior ◽  
Absorption Lines ◽  
Photometric Study ◽  
Short Term ◽  
Photometric Observations ◽  
Shell Star

AbstractWe report on combined spectroscopic and photometric observations of EW Lac during its outburst of 1983. At this time the star’s Hα and Hβ lines showed strong doubled-peaked emission profiles which were variable with time. UBV photometry exhibited a long-term and frequent erratic short-term variations. The amplitude of U, B and V variations reached about 0.3 magnitude on October 15, 1983. Both Hβ emission and the structure of the shell absorption lines of the star also displayed anomalous behavior in 1983. It is evident that this star was in a strong active phase at that time.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

scholarly journals Study of variability of 2MASSJ10183905+0014078 stellar objects

2019 ◽  
pp. 60-65
Author(s):  
E. C. Romas
Keyword(s):  
Spectral Characteristics ◽  
Type Ii ◽  
Slow Increase ◽  
Stellar Objects ◽  
X Ray ◽  
Spectral Class ◽  
Photometric Observations ◽  
Type Object ◽  
Brightness Variability ◽  
Made In

This paper presents observational data for the star 2MASSJ10183905+0014078 (UCAC4 452-048383), in which so far no brightness variability has been detected. However, photometric observations made in 2015 allowed recording are activity with an amplitude of 0.8 m for this star. The star parameters, namely magnitude and color index (V0 = 7.59, (B - V)0 = 1.19) and, therefore, the position on the Hertzsprung-Russell diagram, luminosity (L☉ = 0.1), spectral class (K7), mass (M☉ = 0.6), the spectral characteristics in the optical (Ca, Fe, Na D, H_ lines, Mg H, and TiO bands) and X-ray ranges allow us to classify the star as UVCet type object. The ash profile can be attributed to type II, with a relatively slow increase and decrease in brightness.

scholarly journals Visions of Human Futures in Space and SETI

2017 ◽  
Author(s):  
Jason T. Wright ◽  
Michael P. Oman-Reagan
Keyword(s):  
Solar System ◽  
Science Fiction ◽  
Dark Matter Particle ◽  
Short Term ◽  
National Science ◽  
The Galaxy ◽  
Near Future ◽  
Far Future ◽  
Made In

We discuss how visions for the futures of humanity in space and SETI are intertwined, and are shaped by prior work in the fields and by science fiction. This appears in the language used in the fields, and in the sometimes implicit assumptions made in discussions of them. We give examples from articulations of the so-called Fermi Paradox, discussions of the settlement of the Solar System (in the near future) and the Galaxy (in the far future), and METI. We argue that science fiction, especially the campy variety, is a significant contributor to the ‘giggle factor’ that hinders serious discussion and funding for SETI and Solar System settlement projects. We argue that humanity's long-term future in space will be shaped by our short-term visions for who goes there and how. Because of the way they entered the fields, we recommend avoiding the term ‘colony’ and its cognates when discussing the settlement of space, as well as other terms with similar pedigrees. We offer examples of science fiction and other writing that broaden and challenge our visions of human futures in space and SETI. In an appendix, we use an analogy with the well-funded and relatively uncontroversial searches for the dark matter particle to argue that SETI's lack of funding in the national science portfolio is primarily a problem of perception, not inherent merit.Also on arXiv: https://arxiv.org/abs/1708.05318Please cite this version:Wright, Jason T., and Michael P. Oman-Reagan. “Visions of Human Futures in Space and SETI.” International Journal of Astrobiology, 2017, 1–12. doi:10.1017/S1473550417000222.

scholarly journals Progress in Pediatric Kidney Transplantation

2014 ◽  
Vol 7 (1) ◽  
pp. 115-122
Author(s):  
Jodi M. Smith ◽  
Vikas R. Dharnidharka
Keyword(s):  
Kidney Transplantation ◽  
Graft Survival ◽  
Pediatric Population ◽  
Short Term ◽  
Allocation Policy ◽  
Pediatric Kidney Transplantation ◽  
Timely Access ◽  
The Impact ◽  
Made In

Significant progress has been made in pediatric kidney transplantation. Advances in immunosuppression have dramatically decreased rates of acute rejection leading to improved short term graft survival but similar improvements in long term graft survival remain elusive. Changes in allocation policy provide the pediatric population with timely access to transplant but there remains concern about the impact of less HLA matching and a decrease in living donors. This report presents data from North America on these successes and the ongoing challenges that face the pediatric transplant community.

The 1981 Elections and the Changing Fortunes of the Israeli Labour Party

1981 ◽  
Vol 16 (4) ◽  
pp. 432-446
Author(s):  
Yael Azmon
Keyword(s):  
Time Perspective ◽  
Labour Party ◽  
Political Support ◽  
The Political ◽  
Short Term ◽  
Frequent Use ◽  
Made In

ONE OF THE INNOVATIONS OF THE 1981 ELECTIONS IN ISRAEL which caught the eye, was the frequent use of ‘this time’ in campaign slogans. ‘This time only the Labour Alignment!’ ‘This time the Likud!’ shouted the slogans from all the billboards. This is an appeal to political support based on a short-term time perspective. This appeal differs greatly from that which characterized the Israeli ideological, mass-membership parties in previous periods.The change in party slogans is a response to changes in the electorate. These changes in the electorate are most clearly reflected in the magnitude of the ‘undecided‘ vote and of its oscillation between different parties. The ‘undecided’ vote which used to be very low, amounted to about 40 per cent according to polls made in 1977 in the preelection period, and to about 30 per cent in the period preceding the 1981 elections. Moreover, the polls pointed to a particularly great oscillation of the electorate in the pre-1981 election period: the political forecast in December 1980 was around 60 Labour seats and around 28 Likud seats. In the beginnin of June 1981, the pendulum swung. The forecast for Labour fell to 30-33 seats while of Likud rose to 47 or even 49 seats. In the elections the race between Likud and Labour was very close. The results were 47 to Labour and 48 to Likud (as against 32 Labour and 43 Likud in 1977).

Early Blue Excess from the Type Ia Supernova 2017cbv

2017 ◽  
Vol 14 (S339) ◽  
pp. 47-49
Author(s):  
G. Hosseinzadeh
Keyword(s):  
Light Curve ◽  
Standard Type ◽  
Circumstellar Material ◽  
Type Ia Supernova ◽  
Unusual Distribution ◽  
Photometric Observations ◽  
Type Ia ◽  
Optical Light Curve ◽  
Ia Supernovae

AbstractThis paper presented very early, high-cadence photometric observations of the nearby Type Ia SN 2017cbv. The light-curve is unique in that during the first five days of observations it has a blue bump in the U, B, and g bands which is clearly resolved by virtue of our photometric cadence of 5.7 hr during that time span. We modelled the light-curve as the combination of an early shock of the supernova ejecta against a non-degenerate companion star plus a standard Type Ia supernova component. Our best-fit model suggested the presence of a subgiant star 56 R⊙ from the exploding white dwarf, although that number is highly model-dependent. While the model matches the optical light-curve well, it over-predicts the flux expected in the ultraviolet bands. That may indicate that the shock is not a blackbody, perhaps because of line blanketing in the UV. Alternatively, it could point to another physical explanation for the optical blue bump, such as interaction with circumstellar material or an unusual distribution of the element Ni. Early optical spectra of SN 2017cbv show strong carbon absorption as far as day –13 with respect to maximum light, suggesting that the progenitor system contained a significant amount of unburnt material. These results for SN 2017cbv illustrate the power of early discovery and intense follow-up of nearby supernovæ for resolving standing questions about the progenitor systems and explosion mechanisms of Type Ia supernovæ.

Symbiotic Stars in the Local Group of Galaxies: POINT-AGAPE Catalogue Revisited

2017 ◽  
Vol 14 (S339) ◽  
pp. 291-294
Author(s):  
K. Drozd ◽  
J. Mikołajewska ◽  
M. Darnley ◽  
K. Iłkiewicz ◽  
N. Caldwell ◽  
...  
Keyword(s):  
Light Curve ◽  
Local Group ◽  
Light Curves ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
Original Point

AbstractThis research was prompted by the discovery of 35 new or candidate symbiotic stars during a targeted search in the Local Group of Galaxies. A catalogue of a further 200 or so such objects has now been compiled. Many of them could be identified with counterparts in the POINT-AGAPE Catalogue. However, information in the Catalogue is limited to position, brightness and possible period, and light-curves are not available. The poster presented an example of a light-curve of a symbiotic star retrieved from original Point-Agape Catalogue data.

scholarly journals The Long-term Variation in the RV Tauri Star U Mon

1995 ◽  
Vol 155 ◽  
pp. 409-410 ◽  
Author(s):  
Karen R. Pollard ◽  
P. L. Cottrell
Keyword(s):  
High Resolution ◽  
Light Curve ◽  
Radial Velocity ◽  
Tauri Star ◽  
Short Term ◽  
Instability Strip ◽  
Term Variation ◽  
Velocity Variations

The RV Tauri stars are semiregular pulsating variables located in the brightest part of the Cepheid II instability strip. They have a characteristic light curve of alternating deep and shallow minima. A subset of the RV Tauri stars (the RVb subclass) exhibit long-term (500 to 2600 day) light and radial velocity variations. Although it is well established that the short-term variations are due to pulsations, the long-term behaviour is not well understood.BVRI photometry and high-resolution spectra of U Mon (the brightest member of the RVb subclass) were obtained at the Mt John University Observatory (MJUO) between 1990 Aug and 1994 May. The light and colour curves obtained clearly show the long-term variation in U Mon (Fig. 1(a) and (b)). The reddest colours occur slightly later than the long-term minimum in the light curve. The short-term light and colour variations are ‘damped’ at the long-term minimum.

scholarly journals Circular Polarimetry of AM Herculis

1983 ◽  
Vol 72 ◽  
pp. 207-210
Author(s):  
V. Piirola ◽  
O. Vilhu ◽  
I. Tuominen
Keyword(s):  
Circular Polarization ◽  
Magnetic Axis ◽  
Light Curves ◽  
Short Term ◽  
Probable Explanation ◽  
Photometric Observations ◽  
Peak Value

ABSTRACTCircular polarimetry in the red and simultaneous photometric observations in the UBVRI bands during the period June 1-3, 1981, are discussed. The peak value of negative circular polarization PV ~ -15 % is stronger than observed in 1976-79. Variations in the shape of the polarization and light curves occur from night to night. The positive crossover and reversal of the sign of the circular polarization are only marginal. A probable explanation of the short term variations seems to be the changing shape and position of the accretion columns with respect to the magnetic axis

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