Observation and analysis of SAO78352 on Nov. 24, 2010 (UTC)

Dec. 18, 2010
Kazuhisa Miyashita

The occultation event of this star was observed by H. Karasaki on Nov. 24, 2010.
The observed time of step's length is larger than expected. There are a number of opportunities to re-observe this star coming in the next few months. Observation of this star is highly desired.

Catalogue details

Catalogue details

XZ 9016 = SAO 78352
RA =   6 25 34.1961   PM = 0.00060s
Dec =  22 27 28.026    PM = -0.0171"
Mv = 7.23, Mb = 0.00, Mr = 0.00    Spectrum A3    Dia: .0000" [Estimated]

Star is the mean position of the following pair
Name    Cmpt   Yr1  Yr2: PA1   PA2  :   Sep1   Sep2  :  Mag1  Mag2:     #1      #2  mean
STT 139       1843 2008: 313.0 257.0:   0.800   0.700:  7.33  9.38: S 78352  ------ mean

WDS Discoverer codes
STT

Orbital elements
Name  Cmpt     Period       a"        i       node      T        e       peri
STT 139        360.30000  0.674000  56.6000 183.8000 1929.06000 0.89400 276.3000
Year   PA    Sep
2008 258.48  0.56
2009 258.83  0.56
2010 259.18  0.57
2011 259.53  0.57
2012 259.87  0.57

Light curve and explanation

Karasaki's observation

The air scintillation on this observation is very large, as you see the light curve. I analyzed this Karasaki-san's video with PSF tracking and PSF photometry to reduce the background noise. As a result, a rather clear step is obtained. Karasaki-san also confirmed it with his analysis.

Comment from IOTA double star coordinator

Brian Loader IOTA double star coordinator says:

Thank you for this observation of S78352 by Karasaki-san. It certainly looks a clear step, despite the effect of poor seeing.
Using the positions from the orbit as above, the expected step time was -1.11 seconds. But the data for the double is confused. The WDS shows a separation of 0.7" at 2008, the interferometric catalog has the lower separation, 0.57". Using 0.7" instead of 0.57" gives a step of -1.36 seconds, much closer to Karasaki-san's -1.45 seconds.

This is the first observation I have had for this pair. There are a number of opportunities to re-observe this star coming in the next few months, so hopefully there may be some more timings.

Orbit and observations