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2008

Light Curves

Light curves of asteroid periods found in 2008.  All period are light time corrected. The criteria for target selection in Kingsgrove observatory were mainly for its favourable opposition brightness and also its southerly location due to local restrictions to the  observatory’s northern horizon. Observing is useful for photometry in dark sky(moonless) to about 14.5magnitude. Leura observatory limiting magnitude is 17.5magnitude with precision of <0.03m.
System used and location  :

1. SCT 0.25m f/5.2 (Meade focal reducer) , CCD Camera SBIG ST402ME                                                                             
                  Location  E19
2. SCT 0.35m f/7 (Lumicon Giant Easy Guider reducer) , CCD camera SBIG ST 9 XE               
                                                                Location E17

178 Belisana*
Second attempt for 178 Belisana on its 2008 apparition. This time observations will be by Frederick Pilcher  from Organ Mesa observatory USA along with another observer,Vladimir Benishek from Serbia. We will form a long baseline that will resolve the ambiguity that was found in the 2007 apparition published in MPB 35-3. 178 Belisana mean PAB in 2007 is 246.5. A difference of about 130 deg from 2008 apparition. If in 2007 the aspect is pole-on then the 2008 apparition  the asteroid is tilted at about 45 latitude. Which means that as observations progressed through opposition this year, amplitude will be reduced further and eventually the first harmonic will start to dominate showing only a monomodal lightcurve.
My data obtained on 31/08 and 01/09 was linked by using the same comparison stars on both nights. The current lightcurve is most likely be bimodal.  

Date range 31/08 - 22/09: Period 12.3264h + 0.0008h: Amplitude 0.22m + 0.02m
H=9.38: D=41.68: Albedo=0.180: Class=S: PA=17.9: LPAB=19.2: BPAB =-1.5

226 Weringia*

Returning follow up target. Previous work Oey(2007) suggest a period of 11.240h +/- 0.002h.

Date range: 06/11 - 22/12: Period: 11.149h + 0.002h: Amplitude: 0.15m + 0.02m
H = 9.70:D = 48.25: Albedo = 0.100: Class = SC: PA=10.4, 6.9, 10.9: Lpab=65 : Bpab=-18

315 Constantia
Target of opportunity in the same field as 2066 Palala. Previous period derived by Behrend et al.(2008) at 5.37h with U=2- with amplitude of 0.11m showing a monomodal light curve indicating a polar orientation. Current work showing a more favourable orientation showing a large amplitude bimodal lightcurve .

Date range: 02/07 - 03/07(1): Period: 5.345h + 0.003h: Amplitude: 0.60m + 0.02m
H = 13.20: D=7.18: Albedo = 0.180: Class=S: PA= 19.5: LPAB= 246 : BPAB=3

357 Ninina*

The low amplitude and unclear period obtained for the 6 hour session in 2008 shows no changes compare to the 2007 result. The lack of clear light curve shape and the availability of the new Canopus version 9.5.0.10 with the comp star selector module prompt me to reprocess the data. Once internally linked to the correct zero point, the analysis showing the period of 53.63h in contrast with the previously found period of 34.97h by Behrend et al. Further observation will be conducted to determine the correct period during the next apparition/opposition on the 27th Jan 2010.

Date range=11/04/08 - 03/05/08  (1): Period= 17.156h + 0.002h: Amplitude= 0.18m + 0.03m
H= 8.72: D=  99.5km: Albedo= 0.058: Class= C:
PA(07) = 7, 1, 3: Lpab(07)= 310: Bpab= 3
PA(08)= 19: Lpab(08)=50: Bpab= -15

552 Sigelinde*
CALL targets and the usual selection criteria.

Date range:11/04/08 - 03/05/08  (1) : Period: 17.156h + 0.002h: Amplitude: 0.18m + 0.03m
H=9.39: D=73km: Albedo=0.058: Class=C: PA=14.2 - 8.9: LPAB=240: BPAB= -5


677 Aaltje*
Call target in 2007.
Followed up work in 2008 apparition. The 2007 data was plagued with numerous background stars and the inevitable short sessions.

The 2008 data taken on 15/07 and 17/07 were linked using the same comparison stars. So does the data on 17/07 and that on 18/07. This confined the period to 16.7 and later confirmed with subsequent collection of data. The bimodal light curve formed fit well with a period of 16.6076h.

Date range:11/04/08 - 03/05/08  (1): Period: 17.156h + 0.002h: Amplitude: 0.18m + 0.03m
H=9.39: D=73km: Albedo=0.058: Class=C: PA=14.2 - 8.9: LPAB=240: BPAB= -5




741 Botolphia

Date range: 30/05 - 31/05(1): Period: 23.24h: Amplitude: 0.2m


788 Hohensteina*

CALL targets. Previous data shows a period of 11.16h+/-0.09h(Behrend et al.(2008)).
Work in collaboration with Dr. Michael Fauerbach. 3 nights of combined long run between US and Australia allow us to constrain the period to the one described here. Any further refinement of period has to be done in the next apparition perhaps with collaboration with even wider geographical location.
Indication of NPA rotation (Harris private correspondence

Date range: 11/04/08 - 31/05/08(1): Period : 37.176h + 0.004h: Amplitude: 0.18m + 0.03m
H = 8.3 : Dia= 120 : Albedo = 0.058 : Class = C: PA (2008)= 8.2 , -12.8: LPAB(2008) = 220: BPAB(2008) = 12

929 Algunde*

PSABA target. Second apparation.

Date range: 30/07 - 02/08: Period=3.3110h + 0.0008h: Amplitude= 0.13m + 0.02m
H = 12.10: Dia = 11.91: Albedo = 0.180 : Class =S: PA: 15: LPAB = 340: BPAB =8.5

1122 Neith*

CALL target.
Since observations/project was completed for 788 Hohensteina, work has been done revolving around multiple sessions with common comparison stars ie internal linkages spanning multiple sessions. The criteria to start an observation of a target will be to begin around 1-2 months prior to opposition. During this time the asteroid is in the inflection path toward retrograde motion and it appear stationary for a few days. If the target turn out to be a slow rotator, the few continuous observing sessions can be linked and amplitude with the initial segment of the light curve can also be determined.
Session 883 consist of data from 31/08 and 01/09, session 898 consist of data from 10/09 and 11/09. Current observing run includes 178 Belisana, 2543 Machada, 4332 Milton

Date range:31/08 - 29/09: Period=12.599h + 0.006h: Amplitude= 0.08m + 0.02m
H=11.10: Dia=18.88: Albedo=0.180: Class=S: PA=18.2: LPAB = 6.7: BPAB=-6.1


1449 Virtanen*

CALL target. Long period. Period constrained when multiple sessions were linked together due to target slow movement sharing common comparison stars.

Date range: 30/05 - 08/07 (1): Period= 30.495h + 0.005h: Amplitude= 0.60m + 0.02m
H = 12.4: Dia = 10.37: Albedo = 0.180 : Class =S: PA = 5.8 - 22.8: LPAB = 245.1 - 250.6: BPAB = 7.2, - 4.5


1563 Noel*

Photometric Survey for Asynchronous Binary Asteroid target.

Number of sessions:3: Date range: 03/04 - 05/04 (2): Period= 3.5490h + 0.0008h: Amplitude= 0.15m + 0.02m
H=13.30:Dia=6.85: Albedo=0.180:Class=S: PA=4: LPAB=198: BPAB=5: Data Points=167


1638 Ruanda*

Call target. No known period. Fit well into a trimodal curve. Initially shown to be a bimodal light curve of period 3.157h appear to be caused by significant error  from earlier poor quality data. This also caused the false detection of an event.

Number of sessions: 5: Date range= 11/05 - 23/06 (1): Period= 4.2397h + 0.0002h: Amplitude= 0.10m + 0.02m
H=11.50:D=21.06: Albedo=0.100: Class=SC: PA=11.2, - 0.2, - 9.9: LPAB=251, - 254: BPAB=0: Data Points= 247


1785 Wurm*

Photometric Survey for Asynchronous Binary Asteroid target.

Number of sessions= 2 : Date range= 03/03 - 06/03 (2): Period= 3.2696h + 0.0004h:  Amplitude= 0.30m + 0.01m
H = 11.30: Dia = 23.10 : Albedo = 0.100 : Class = SC: PA =3: LPAB = 287.7 :  BPAB = 2.5

1836 Komarov*

CALL target

Date range= 11/07 - 15/07 (1): Period= 8.081h + 0.002h: Amplitude= 0.39m + 0.02m
H = 11.30: Dia = 23.10 : Albedo = 0.100 : Class = SC: PA =3: LPAB = 287.7 :  BPAB = 2.5

2193 Jackson*

CALL target. No previous known period. Observation finalised with U=3

Date range= 12/04 - 29/04 (1): Period= 4.7541h + 0.0005h: Amplitude= 0.23m + 0.03m
H=10.30: D=48km: Albedo=0.058: Class=C: PA= 9.8, - 3.3: LPAB=226: BPAB= -1



2066 Palala*

CALL target. No previous known period.

Date range= 27/06 - 03/07(1): Period= 9.730h + 0.002h: Amplitude= 0.65m + 0.03m
H=12.50: D=19km~: Albedo= 0.0491: Class=S: PA= 17.6, -19.8: LPAB= 246: BPAB= 3.4

2478 Tokai

PSABA target. Synchronous binary follow up work.

Date range= 27/06/08 - 21/07/08  (2) : Period= 25.88h + 0.01h: Amplitude(prim)= 0.40m: Date range=26/01/07 - 05/02/07 (2)
H=12.8: D=8.63km: Albedo = 0.180: Class =S : PA = 9.7 - 3.8 : LPAB = 293 : BPAB = 5


2543 Machado

Amplitude is very low at about 0.02m. Period is difficult to determine. Better precision data was obtained on 20-09-08 with a session length of 7.5h. While large spread still present(0.02m), it shows an amplitude of 0.02m with bimodal curve and if it was a polar aspect in 2007, the amplitude should be different and larger in 2008. Therefore with such persistent low amplitude a longer period light curve may be more likely. Further observations should be done to constrain the synodic period.

Period= 5.308h + 0.003h: Amplitude= 0.02m
H=11:Dia=34.82: Albedo=0.058: Class=C: PA=17.0: LPAB=8.1:BPAB=-13.2

2777 Shuksin

Target in the same field as 15268 1990 WF3. Only managed to cover the 2 nights. Period could either be the 3.88h or possibly long rotation period of more than 100h based on data supplied by R. Stephens. Other collaborators are S. Gajdos and  P. Kusnirak

Date range: 27/08- 28/08: Period: 3.87h + 0.02h: Amplitude: 0.05m + 0.03m
H = 13.10: Dia= 7.51: Albedo= 0.180: Class=S: PA=14.7: Lpab=6.6 :Bpab= -3.8

3576 Galina*

PSABA target.

Date range=01/10-08/10: Period= 5.910h + 0.003h: Amplitude= 0.04m + 0.01m
H=13.10:D=7.51: Albedo=0.180:Class=S: PA=3: LPAB=  9 :   BPAB=  -3    

4182 Mount Locke*

Target was suggested by Behrend as a suspect binary. attenuation noted at the end of session 868 is associated with poor atmospheric condition at an altitude of about 30deg. This color effect was later reprocessed and removed that eventually neutralise the light curve.

Date range=13/08 - 02/09: Period= 3.0175h + 0.0003h: Amplitude= 0.15m + 0.03m
H=12.20: D=15.26km: Albedo=0.100: Class=SC: PA= 5.0, - 9.2: LPAB=323 : BPAB=9.5


4332 Milton*

CALL target. No specific aim accept that its part of observations with 178 Belisana.

Date range= 31/08 - 11/09: Period= 3.2978h + 0.0003h: Amplitude= 0.30 + 0.05m
H=11.90: D=13.06km: Albedo=0.180: Class=S: PA=28, - 24: Lpab=18, - 21: Bpab= -10

5034 Joeharrington*

CALL target. No previous known period

Date range=02/05 - 06/05(1) : Period= 8.417 + 0.004h: Amplitude=0.35m + 0.03m
H= 12.9: D= 8.24:     Albedo= 0.180: Class= S L: PA=8 : LPAB=233 : BPAB=-6.3

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Bracket next to Date Range indicate the location and system used. All period are light time corrected. An asterisk (*) after the name indicate published light curve in Minor Planet Bulletin.
PSABA: Photometric Survey of Asynchronous Binary Asteroids. CALL: Collaborative Asteroid Light curve Link


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