R Ara (HD149730)
Aim of the campaign
R Ara is thought to be a semidetached binary system. A close (~4 arcsec) companion and variability of about 0.1 mag on time scales of around a day make it difficult to interpret the light curves. R Ara has been poorly observed.
The initial aim is to determine accurate Time of Minimum for several primary and secondary eclipses.
We will repeat TOM measurements each season in order to accurately determine the period.
{tab Data}
| STAR | Max V Mag | RA 2000 | BRNO epoch (HJD) | BRNO period | Primary / secondary |
| R Ara | 6.17 | 16h39m44.7s | 2455347.1559 | 4.425135 | p |
| Min V Mag | DE 2000 | Krakow epoch (HJD) | Krakow period | ||
| 7.32 | -56°59′ 40″ | 2452501.5596 | 4.4251133 |
{tab Light Curve}
From Nield, K. M. Astrophysics and Space Science 180: 233-252, 1991.
{tab Observing}
A mag 7.8 star only 3.8 arcsec from R Ara will interfere with measurements. This is not a problem for TOM measurements.
There is also variability of the order of 0.1 mag on time scales of about a day. This will complicate TOM measurements, therefore number of eclipses will need to be recorded.
{tab Finder Chart}
The field of RS Sgr is shown in the plot below.
{tab Comparison Star Data}
Please use the four comparison stars labled on the chart and catalogue values listed below.
| Comp Star | Name | RA (J2000) | DEC (J2000) | V | B-V | V-Rc |
| 1 | HD 150898 | 16 47 19.66 | -58 20 29.0 | 5.570 | -0.095 | -0.043 |
| 2 | HD 150745 | 16 46 21.23 | -58 30 12.8 | 5.728 | -0.110 | -0.115 |
| 3 | HD 151688 | 16 52 09.00 | -57 34 49.1 | 7.134 | -0.057 | -0.093 |
| 4 | HD 150577 | 16 45 02.47 | -55 43 08.5 | 7.924 | 0.006 | -0.072 |
{tab Preliminary Results}
No data yet.
{/tabs}