A NEW DEEP LOW STATE OF TT ARI?

2011 ◽  
Author(s):  
N. D. Melikian ◽  
V. S. Tamazian ◽  
J. A. Docobo ◽  
A. A. Karapetian ◽  
G. S. Kostandyan ◽  
...  
Keyword(s):  
Tt Ari

scholarly journals UV Spectroscopy of the Novalike Variable TT Arietis

1982 ◽  
Vol 69 ◽  
pp. 453-454
Author(s):  
W. Wargau ◽  
H. Drechsel ◽  
J. Rahe ◽  
G. Klare ◽  
B. Wolf ◽  
...  
Keyword(s):  
Uv Spectroscopy ◽  
Wavelength Region ◽  
Apparent Magnitude ◽  
Long Wavelength ◽  
Dwarf Nova ◽  
Tt Ari ◽  
Visual Brightness

TT Ari was detected by Strohmeier et al. (1957) and is classified as a novalike variable. It was hitherto unclear whether TT Ari is a special type of dwarf nova (Warner, 1976) or an old nova (Cowley et al., 1975). Our group obtained a total of four IUE spectra between 1979 and 1981 in the short and long wavelength region. The first spectrum was taken in July 1979, when the system had a visual brightness of 11.3 magnitudes. The following two IUE observations in November 1980 revealed TT Ari in the lowest optical state (V = 14m.3) observed so far. The fourth spectrum was obtained during the rise to maximum in January 1981, when the system had an apparent magnitude of V = 11m.8. From this behavior, Krautter et al. (1981) concluded that TT Ari is a dwarf nova with extremely extended standstills as they are typical for Z Cam stars.

scholarly journals TT ARI–94: A Study of 1.6…60 Minute Variability

1996 ◽  
Vol 158 ◽  
pp. 37-40
Author(s):  
I. L. Andronov ◽  
K. Arai ◽  
L. L. Chinarova ◽  
N. I. Dorokhov ◽  
T. A. Dorokhov ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Time Scales ◽  
Cycle Length ◽  
Cataclysmic Variables ◽  
Optical Data ◽  
Private Communication ◽  
American Continent ◽  
Frequency Range ◽  
Wide Range ◽  
Tt Ari

We report photometric results from 44 runs at 11 observatories during the international campaign ‘TT Ari–94’. No coherent oscillations in the frequency range 10… 900 cycle d−1 are found. The highest peaks in the power spectrum cover the wide range of 28… 139 cycle d−1. Variations occur at a few preferred time-scales rather than at one cycle length, with a possible secular decrease. In the frequency range 90… 900 cycle d−1 the power spectrum obeys a power law with slope γ ranging from 0.8 to 2.6 for different runs.TT Ari is one of the brightest cataclysmic variables and remains one of the most interesting objects of this class. It exhibits a variety of phenomena observed at time-scales from seconds to months. A recent detailed photometric study of this object and a bibliographical overview may be found in Tremko et al. (1996). Tremko et al. (1992, 1993, 1994) discuss aspects of the TT Ari–88 campaign. Our campaign TT Ari–94 was unprecedented, as the observations were longitude-dispersed, from Japan through Turkmenia, to Europe and the American continent. Moreover, our optical data on October 7 partially overlap with the HST observations obtained by Home & Welsh (1995, private communication). The numerical results of observations obtained during these nights are shown in Table 1.

scholarly journals Multiple Time Scales in Cataclysmic Variables: The Examples

1995 ◽  
Vol 151 ◽  
pp. 302-305
Author(s):  
Ivan L. Andronov
Keyword(s):  
Power Law ◽  
Accretion Rate ◽  
Power Index ◽  
Cataclysmic Variables ◽  
Power Spectra ◽  
Theoretical Explanation ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Solar Type ◽  
Tt Ari

AbstractDecades of patrol observations of cataclysmic variables (CVs) show variations of the accretion rate also at a time scale of a few years which may be explained by a solar-type activity of the secondary and/or by orientation changes of the magnetic axis of the white dwarf in polars. Secondary photometric periods seen in TT Ari and possibly some other CVs need theoretical explanation. Irregular variability of some objects is characterized by power-law power spectra with a power index depending on the luminosity state of the system.

The Variable Nature of TT Ari in the Ultraviolet

1995 ◽  
pp. 179-179
Author(s):  
C. R. Robinson ◽  
F. A. Córdova ◽  
G. S. Stringfellow
Keyword(s):  
Variable Nature ◽  
Tt Ari

scholarly journals TT Arietis: 40 yr of photometry

2019 ◽  
Vol 489 (2) ◽  
pp. 2961-2975 ◽  
Author(s):  
Albert Bruch
Keyword(s):  
Time Scales ◽  
Orbital Period ◽  
Primary Component ◽  
Photometric Data ◽  
Light Curves ◽  
Average Period ◽  
High State ◽  
Periodic Oscillations ◽  
First Time ◽  
Tt Ari

ABSTRACT In an effort to characterize variations on the time-scale of hours and smaller during the high and low states of the nova-like variable TT Ari, light curves taken over the course of more than 40 yr are analysed. It is found that the well-known negative superhump observed during the high state persists until the present day at an average period of 0.132 95 d, which is slightly variable from year to year and exhibits substantial amplitude changes. The beat period between superhump and orbital period is also seen. Quasi-periodic oscillations occur at a preferred quasi-period of 18–25 min and undergo a systematic frequency evolution during a night. The available data permit for the first time a detailed investigation of the low state that is highly structured on time-scales of tens of days. On hourly time-scales, the light curve exhibits strong variations that are mostly irregular. However, during an interval of several days at the start of the low state, coherent 1.2 mag oscillations with a period of 8.90 h are seen. During the deep low state, quiet phases and strong (1.5–3 mag), highly structured flares alternate in irregular intervals of roughly 1 d. The quiet phases are modulated on the orbital period of TT Ari, suggesting reflection of the light of the primary component off the secondary. This is the first time that the orbital period is seen in photometric data.

Spectral Observations of the Novalike Star TT Ari

Astrophysics ◽  
2004 ◽  
Vol 47 (4) ◽  
pp. 462-471
Author(s):  
N. D. Melikian ◽  
A. A. Karapetian
Keyword(s):  
Tt Ari

scholarly journals Infrared, optical and ultraviolet observations of TT Ari

1982 ◽  
Vol 200 (2) ◽  
pp. 455-462 ◽  
Author(s):  
R. F. Jameson ◽  
A. R. King ◽  
M. R. Sherrington
Keyword(s):  
Ultraviolet Observations ◽  
Tt Ari

scholarly journals X-Ray Observations of VY Scl-Type Nova-Like Binaries in the High and Low State

2015 ◽  
Vol 2 (1) ◽  
pp. 269-272
Author(s):  
P. Zemko ◽  
M. Orio
Keyword(s):  
Previous Article ◽  
X Rays ◽  
High State ◽  
Plasma Model ◽  
X Ray ◽  
Polar Caps ◽  
Thermonuclear Burning ◽  
Best Fit ◽  
Tt Ari

Four VY Scl-type nova-like systems were observed in X-rays both during the low and the high optical states. They are BZ Cam, MV Lyr, TT Ari, and V794 Aql. Using archival ROSAT, <em>Swift</em> and <em>SUZAKU</em> observations we found that the X-ray flux for BZ Cam is higher during the low state, but there is no supersoft X-ray source (SSS) that would indicate the thermonuclear burning predicted in a previous article. The X-ray flux is lower by a factor 2–10 in the low than the high state in other systems, and does not reflect the drop in <em>˙M</em> inferred from optical and UV data. The best fit model for the X-ray spectra is a collisionally ionized plasma model. The X-ray flux may originate in a shocked wind or in accretion onto polar caps in intermediate polar systems that continues even during the low state.

Photometry of TT Arietis

1987 ◽  
Vol 93 ◽  
pp. 167-174
Author(s):  
I. Semeniuk ◽  
A. Schwarzenberg-Czerny ◽  
H. Duerbeck ◽  
M. Hoffmann ◽  
J. Smak ◽  
...  
Keyword(s):  
Beat Period ◽  
Photometric Observations ◽  
Tt Ari

AbstractAn analysis of data spanning 24 years shows that a secondary 20m periodicity is a persistent feature in photometric observations of TT Ari. This period decreases from 27m in 1961 to 17m in 1985. The 4d beat period of photometric and spectroscopic periods is also apparent in observations of 1966.

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