Doublestar analysis of lunar occultation of SAO146617 in Dec.6 2008
Observed by Hiroyuki Tomioka
Calculated by Kazuhisa Miyashita
Observation
Tomioka's report:
Place name Hitachi, Ibaraki, Japan
20080518103122.71 S158556 DD EG G0.04 1 W 21 13AA
20080518103127.80 X128805 DD EG G0.04 3 E 21 13AA
A faint star, which has 10 magnitude brightness, is visible. It might be a component of the star of previous event.
Catalogue details
XZ double star file
XZ 31441 = SAO 146617
RA = 23 17 37.6247 PM = 0.01720s
Dec = - 1 31 17.958 PM = -0.0890"
Mv = 7.86, Mb = 0.00, Mr = 0.00 Spectrum G5 Approx dia. .0000"
Star is component A in the following system
Name | Cmpt | Yr1 | Yr2: | PA1 | PA2 : | Sep1 | Sep2 : | Mag1 | Mag2 |
BU 79 | AB | 1876 | 1999: | 115.0 | 16.0: | 1.000 | 1.600: | 8.25 | 9.73 |
BU 79 | AC | 1894 | 1900: | 157.0 | 161.0: | 16.000 | 16.200: | 8.20 | 16.70 |
WDS Discoverer codes
BU Burnham, S.W.
Orbital elements
Name | Cmpt | Period | a" | i | node | T | e | peri |
BU 79 | AB | 388.35000 | 1.990000 | 108.1000 | 8.8000 | 2045.00000 | 0.49000 | 75.8000 |
Washington Double Star Catalog (WDS)
WDS Discovr Comp | EPOCH | # THETA | | RHO | | Magnitudes | Spectra |
Identifier | Frst Last | Fst Lst | | First | Last | Pri | Sec | Type |
23176-0131BU 79AB | 1872 2006 | 133 120 | 14 | 1.0 | 1.7 | 8.23 | 9.59 | G5 |
Prediction
by OCCULT Ver.4
| | day | Time | P | Star | Sp | Mag | Mag | % | Elon | Sun | Moon | CA | PA | VA | AA | Libration | A | B | RV | Cct |
y | m | d | h m s | | No | D | v | r V | ill | | Alt | Alt Az | o | o | o | o | L B | m/o | m/o | "/sec | o |
08 | Dec | 6 | 7 47 34 | D | 146617 | SG5 | 7.9 | | 54+ | 94 | -5 | 49 154 | 37N | 14 | 34 | 36 | -7.8 -3.5 | +0.6 | +2.6 | .306 | 36 |
146617 is triple: AB 8.3 9.7 1.4" 11.9 : AC 8.2 16.7 19.8" 233.6
Calculation
Position angle around Lunar limb is same as component's position angle of this double star.
In this case, the separation of components is simply given as:
Sp = RV * dT
where Sp is separation of components; RV is Radial Velocity - the radial rate of motion of the star relative to the lunar limb, in arcsecs per second.;
dT is the difference of event time of two components.
Time difference 5.51 second obtained from observation. Hence the separation is:
Sp=0.306 * 5.51 = 1.69
It is close to value descripted on WDS catalogue.
Conclusion
The separation of component of double star BU 79 (SAO146617) is confirmed by occultation observation. A result of occultation analysis agrees with WDS catalogue value.