Photomrtry and Astrometry for double star XZ101356

Jan. 11, 2009
Kazuhisa Miyashita

in Japanese

Catalogue details of this star

XZ101356 is following pair described in WDS.
Catalogue details

 XZ 101356
 RA =   7 25 59.0941   PM = -0.00093s
Dec =  22  5 14.998    PM = -0.0152"
 Mv = 9.84, Mb = 10.33, Mr = 9.58    Spectrum __    Approx dia. .0001"

Star is the primary of the following pair
Name    Cmpt   Yr1  Yr2: PA1   PA2  :   Sep1   Sep2  :  Mag1  Mag2:     #1      #2  mean
AG  140       1898 1992: 178.0 175.0:   1.600   1.900:  9.89 10.57: X101356 X 11071

WDS Discoverer codes
AG   Astronomische Gesellschaft          


Doublestar Report to IOTA coordinator

H. Karasaki's observation
2009 Nov  7 at 17h 14m

Star = X101356
Observer =  H. Karasaki
Telescope =  20.0cm at  139 40  1.2  35 44 25.3

Double star details from the XZ catalogue
Star is the primary of the following pair
AG  140       1898 1992: 178.0 175.0:   1.600   1.900:  9.89 10.57: X101356 X 11071

Observation details
Star Mag = 9.84
   Event = R D
      PA = 279.004
      AA = 271.959
       l = 0.411
       b = -0.237
      RV = 0.4059
     CCT = -173.87
      T1 = 23.33
   T2-T1 = 1.34
M. Kashiwagura's observation:
2009 Nov  7 at 17h 15m

Star = X101356
Observer =  M. Kashiwagura
Telescope =  30.0cm at  140  8 40.4  38 22 46.9

Double star details from the XZ catalogue
Star is the primary of the following pair
AG  140       1898 1992: 178.0 175.0:   1.600   1.900:  9.89 10.57: X101356 X 11071

Observation details
Star Mag = 9.84
   Event = R D
      PA = 288.594
      AA = 281.553
       l = 0.395
       b = -0.192
      RV = 0.4130
     CCT = 176.65
      T1 = 32.47
   T2-T1 = 1.87

Light curve and Explanation

i) Karasaki's observation (at Nerima, Tokyo, Japan)

Figure 1. Light curve derived from Karasaki's observation

Karasaki-san recorded XZ101356 event with two frames integration. And he found a clear step on the light curve.

ii) Kashiwagura's observation (at Oe, Yamagata, Japan)

Figure 2. Light curve obtained from Kashiwagura's observation


Figure 3. Light curve with Gaussian filtre applied.

Kashiwagura-san also observed XZ1013563 and sent me his video file. The target star is very dim and video is noisy. so I analyzed with Gaussian filtre for image to reduce the background noise, and I also applyed the Gaussian filtre for light curve. As a result of this analysis, rather clear step had been obtained.


Photometry

i) Karasaki's observation

Figure 4. Magnitude of two components from observation.
ii) Kashiwagura's observation


Figure 5. Magnitude of two components from observation.

Magnitude of components
Combined magnitude is assumed 9.13 mag.
                           Brighter component  Fainter component   
Karasaki's observation        9.89 +/- 0.06      10.77 +/- 0.12
Kashiwagura's observation     9.86 +/- 0.05      10.64 +/- 0.11



Astrometry by IOTA coordinator

The effect of the Gaussian filter certainly looks to bring out the step clearly.
Karasaki-san also observed this event, so I have solved for the separation and PA.
These are PA 165.9, separation 1.34", estimated possible errors 3.6 and 0.15".
Predicted PA 171.7, separation 2.0". Solution is attached. The two observations look to be in good agreement.

Best wishes,
Brian

Astrometry by Brian Loader