On the nature of the photometric activity of the T Tauri star V1184 Tau

Stavrev

2009

Astrophys Space Sci

Results from optical photometric observations of the PMS star V 1735 Cyg are reported. The star is located in the IC 5146 dark cloud complex-a region of active star formation. On the basis of observed outburst and spectral properties, V 1735 Cyg was classified as a FUor object. We present data from BVRI CCD photometric observations of the star, collected from March 2003 to January 2009. Plates from the Rozhen Schmidt telescope archive were scanned for a brightness estimation of the star. A sequence of sixteen comparison stars in the field of V 1735 Cyg was calibrated in BVRI bands. The data from photographic observations made from 1986 to 1992 show a strong light variability ( V = 1 m · 2). In contrast, the recent photometric data obtained from 2003 to 2009 show only small amplitude variations ( I = 0 m · 3). The analysis of existing photometric data shows a very slow decrease in star brightness-1 m · 8 (R) for a 44 year period. The possibilities for future photometric investigations of V 1735 Cyg using the photographical plate archives is discussed briefly.

Section: Resultssupporting

confidence: 75%

Photometric study of the FUor star V 1735 Cyg (Elias 1-12)

Stavrev

2009

Astrophys Space Sci

“…A similar superposition of two types of variability is seen on the long-term light curve of another PMS star V1184 Tau (Semkov 2006, Semkov et al 2008. But in this case the observed light curve is due to the phenomena of both: the typical for WTT stars periodic variability (Tackett et al 2003) and variable obscuration from UXor type (Barsunova et al 2006).…”

Section: Resultsmentioning

confidence: 70%

Optical photometry of GM Cep: evidence for UXor type of variability

2011

Astrophys Space Sci

Results from optical photometric observations of the pre-main sequence star GM Cep are reported in the paper. The star is located in the field of the young open cluster Trumpler 37 -a region of active star formation. GM Cep shows a large amplitude rapid variability interpreted as a possible outburst from EXor type in previous studies. Our data from BV RI CCD photometric observations of the star are collected from June 2008 to February 2011 in Rozhen observatory (Bulgaria) and Skinakas observatory (Crete, Greece). A sequence of sixteen comparison stars in the field of GM Cep was calibrated in the BV RI bands. Our photometric data for a 2.5 years period show a high amplitude variations (∆V ∼ 2. m 3) and two deep minimums in brightness are observed. The analysis of collected multicolor photometric data shows the typical of UX Ori variables a color reversal during the minimums in brightness. On the other hand, high amplitude rapid variations in brightness typical for the Classical T Tauri stars also present on the light curve of GM Cep. Comparing our results with results published in the literature, we conclude that changes in brightness are caused by superposition of both: (1) magnetically channeled accretion from the circumstellar disk, and (2) occultation from circumstellar clouds of dust or from features of a circumstellar disk.

“…In some cases, stars originally classified as FUors in detailed spectral and photometric studies were identified as variables of other types. An example is V1184 Tau (CB 34V), which was initially considered to be a FUor, but is now more likely to be a star of UX Ori type (Barsunova et al 2006;). According to Grinin et al (2009), these two types of PMS variability (FUor and UX Ori) can be observed for the same object in different periods of time.…”

Section: Resultsmentioning

confidence: 99%

A long-term photometric study of the FU Orionis star V 733 Cephei

Munari

et al. 2010

A&A

Context. The FU Orionis candidate V733 Cep was discovered by Roger Persson in 2004. The star is located in the dark cloud L1216 close to the Cepheus OB3 association. Because only a small number of FU Orionis stars have been detected to date, photometric and spectral studies of V733 Cep are of great interest. Aims. The studies of the photometrical variability of PMS stars are very important to the understanding of stellar evolution. The main purpose of our study is to construct a long-time light curve of V733 Cep. On the basis of BVRI monitoring we also study the photometric behavior of the star. Methods. We gather data from CCD photometry and archival photographic plates. The photometric BVRI data (Johnson-Cousins system) that we present were collected from June 2008 to October 2009. To facilitate transformation from instrumental measurements to the standard system, fifteen comparison stars in the field of V733 Cep were calibrated in BVRI bands. To construct a historical light curve of V733 Cep, a search for archival photographic observations in the Wide-Field Plate Database was performed. As a result, 192 photographic plates containing the field of V733 Cep were found. Some plates were analyzed at our request to estimate the magnitude of V733 Cep.