Proposal #507

My proposal has been initiated by new research “The Near Infrared and Optical Photometric Activity of V517 Cyg”, kindly presented by author for AAVSO YSO section: https://disk.yandex.com/i/mT54DQvfo-VXEQ
It is noted there, that the IR variability of UX Ori stars is caused by superposition of several different mechanisms rather than only by changes in the extinction along the line of sight. To reveal the role of these mechanisms, it is necessary to obtain long time multi-color photometric observations. In the literature, one may usually find short photometric series, covering a period of about one or several weeks*. However, for UXOri stars with their unpredictable behavior, it is necessary to carry out long-lasting monitoring in order to observe the stars over the entire interval of variations in the optical brightness.
*) It is true for AAVSO database too.

That’s why I propose long-term BVRI monitoring of UXOR V517 Cyg field with BSM telescope. There are some important other targets within 1-deg field:
- UXOR V1977 Cyg;
- 5 INA’s V2016-2020 Cyg;
- carbon SRB V2040 Cyg.
All of them have range about 11-15V and may be reliably detected by BSM.

Optimal frequency of monitoring is 1 BVRI set per night, but in the case of a lack of instrumental time it is possible to observe V517 Cyg every 2-3 nights or every week during some Cygnus seasons.

In order to BSM time optimization I recommend to cancel my other proposal on V351 Gem, due to higher scientifical importance of noted young stellar objects.