Reviced analysis of SAO76103 occultation.

Mar. 14, 2010
Reviced May 3, 2010
Kazuhisa Miyashita

A double star astrometry of SAO76103 has been analyzed with a new observation on Jan. 25.
This is a revision for previtous report on Jan. 11.

The detail of SAO76103 is as follows.
Catalogue details

 XZ 4786 = SAO 76103
 RA =   3 43 41.5348   PM = 0.00148s
Dec =  23 38 56.941    PM = -0.0451"
 Mv = 7.93, Mb = 8.28, Mr = 7.75    Spectrum A9    Approx dia. .0001"

NSV 15745, 7.92, , Type VAR:

Star is the primary of the following pair
Name    Cmpt   Yr1  Yr2: PA1   PA2  :   Sep1   Sep2  :  Mag1  Mag2:     #1      #2  mean
CHR  11       1983 1987: 173.0 157.0:   0.200   0.300:  7.90  8.90: S 76103  ------

WDS Discoverer codes
CHR  Center for High Ang. Res. Astronomy 

The occultation event of this star was observed by Karasaki-san (on Sep. 10 and Dec. 1, 2009 and Jan. 25, 2010), Ishida-san (on Sep. 10, 2009) and Tomioka-san(on Jan. 25, 2010).
Though these events have a small step which consists of only two frames, it is possible to conclude that these observations detected the light change of double star, because all of the event have a similar step. To estimate the position of components, the observed videos were re-analyzed with more accurate diffraction fitting. As a result, separation and position angle between component A and B have been obtained. And the allocation of the component to the event have been decided.
The position of components is:
Separation = 0.047 +/- 0.004"    Position angle = 221.33 +/- 4.76°

The residual of double star solution obtained from five observation is rather small. Therefore, it is possible to say that very closed double is detected and the astrometric position is solved. It is thought that two components which were detected from occultation are allocated to component A and B of WDS CHR11. However the position angle and separation derived from observation are different from catalogue value.

Double star solution by IOTA coordinator

From IOTA doublestar coordinator:
Thank you for this observation of S76103 by Tomioka-san. This fits very well with other observations made by Karasaki-san and Ishida-san. I have generated a new solution or the double. The previous solution using 3 observations by Karasaki (2009 Sep 10, 2009 Dec 12, 2010 Jan 25) and Ishida on 2009 Sep 10 was
separation 0.047+/-0.005" PA 221.11+/-7.36 deg With Tomioka's observation it becomes 0.047+/-0.004" and 221.33+/-4.76 deg.
I have attached the new solution as generated by Occult.

Best wishes

Diffraction fitting

i) Sep. 10, 2009 observed by H. Karasaki

i) Sep. 10, 2009 observed by M. Ishida

iii) Dec. 1, 2009 observed by H. Karasaki

iv) Jan. 25, 2010 observed by H. Karasaki

v) Jan. 25, 2010 observed by H. Tomioka