Observation and analysis of R733 on Jan. 26, 2010 (UTC)

Dec. 11, 2010
Kazuhisa Miyashita


The occultation event of this star was observed by three Japanese observers on Jan. 26, 2010. Steve Messner(USA) also observed it on Nov. 5, 2009. Separation and position angle between component A and B is obtained from these observations. And the magnitude difference is also estimated.
The result of double star astrometry is:
Separation Position angle
  Otained from occultation    0.22+/-0.02"    348.5+/-2.4  degrees
  2005.8690 USNO speckle     0.241"     341.3  degrees 

The catalogue's detail of R733

Catalogue details

 XZ 6268 = SAO 76811 = ZC 733
 RA =   4 53 36.4655   PM = 0.00205s
Dec =  25 21 58.741    PM = -0.0193"
 Mv = 7.21, Mb = 0.00, Mr = 0.00    Spectrum A0    Dia: .0000" [Estimated]

Star is component A in the following system
Name    Cmpt   Yr1  Yr2: PA1   PA2  :   Sep1   Sep2  :  Mag1  Mag2:     #1      #2  mean
CHR 127 AB    1987 2007: 110.0 345.0:   0.100   0.100:  7.42  9.12: R   733  ------
A  1843 AC    1908 2007: 334.0 349.0:   0.200   0.200:  7.30 10.00: R   733  ------

WDS Discoverer codes
A    Aitken, R.G.                        
CHR  Center for High Ang. Res. Astronomy 

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Interferometric catalogue entries

045336.45+252158.9  ADS  3501       CHR 127AB         HD  31033    HIP  22747         04536+2522
    Date       PA          Sep            M1            M2
  1987.7573   109.9   .    0.075    .      .      .      .     .     549  22   3.8   1  McA1989  Sch
  1988.6609   115.7   .    0.093    .      .      .      .     .     549  22   3.8   1  McA1990  Sch
  1989.2292   119.0   .    0.105    .      .      .      .     .     549  22   3.8   1  McA1990  Sch
  1991.2201  V273.    .    0.0484   .      .      .     1.5    .     550  89         1  Osb1996  Occ
  1991.25     308.    .    0.139    .     7.42    .     9.12   .     550       0.3   1  HIP1997a Thp
  1991.9022   135.8   .    0.148    .      .      .      .     .     549  22   3.8   1  Hrt1994  Sch
  1993.8420   140.8  2.    0.174   0.005   .      .      .     .     600       6.0   1  Bag1994  Spe
  1994.8992   325.   4.    0.178   0.008   .      .      .     .     600 200   1.0   1  Bag1999a Spe
  1995.7711   147.2   .    0.196    .      .      .      .     .     549  22   2.5   1  Hrt1997  Sch
  1996.8716   147.6   .    0.199    .      .      .      .     .     549  22   2.5   1  Hrt2000a Sch
  2000.8732   336.3  0.6   0.229   0.002   .      .     1.75  0.02   545  30   6.0   1  Bag2006b Spe
  2005.8690   341.3   .    0.241    .      .      .      .     .     550  24   3.8   1  Msn2009  Sus

045336.45+252158.9  ADS  3501       A  1843AC         HD  31033    HIP  22747         04536+2522
    Date       PA          Sep            M1            M2
  1987.7573   299.8   .    0.519    .      .      .      .     .     549  22   3.8   1  McA1989  Sch
  1991.25        .    .     .       .     7.418  0.102  9.120 0.489  511 222   0.3   1  HIP1997f Thp

Double star solution by IOTA coordinator



Comment from Brian Loader (double star coordinator).

The separations for the points of occultation for your three observers are: Karasaki -0.12" Ishida -0.12" and Kenmotsu -0.13". All similar a might be expected. The - signs indicate the secondary disappeared to the north of the primary (lower PA). (Messner's distance at a reappearance was +0.16", this is also to the north, the sign indicating an increased PA.)

On the profile diagram the three columns of dotted lines span 2".

Using these my slope determinations are now Karasaki -3.0, Ishida -8.4, Kenmotsu -0.55. Ishida is the most difficult and I agree a case could be made for -11.

My best deterimination for a solution, using Messner's observations a well is 0.22"+/- 0.02, 348.5deg +/- 2.4. This compares well with the predicted 0.20" and 349.5.


Photometry


Assuming magnitude of Pair is 7.21 Mag.

Observer            Ishida        Karasaki       Kenmotsu        Catalogue
Brighter star   7.43 +/- 0.04   7.46 +/- 0.06   7.40 +/- 0.04       7.42
Fainter star    9.07 +/- 0.18   8.91 +/- 0.24   9.18 +/- 0.22       9.12

The magnitude difference derived from theree Japanese observations are very close to WDS catalogue's value.

Light curve and explanation

i) Kenmotsu's observation







Kenmotsu-san found a clear step on this event. The magnitude obtained from my analysis is close to the value of catalogue.

ii) Ishida's observation







A clear step like to Kenmotsu-san's observation was found from Ishida-san's video.

iii) Karasaki's observation