(190166) 2005 UP156
B. D. Warner, Center for Solar System Studies-Palmer Divide
Station (CS3-PDS), Landers, CA, USA, and A. W. Harris, MoreData!,
La Cañada, CA, report that CCD photometric observations made
between 2017 May 4 and May 20 show that minor planet (190166)
2005 UP156 is a fully-synchronous binary system with an orbital
period of 40.528 ± 0.0.008 h.
The out-of-eclipse lightcurve shows an amplitude of about 0.4 mag
with eclipse attenuations of 0.53-0.65 mag. The deeper event lasts
about 2.8 hours. The effective secondary-to-primary diameter ratio
is estimated to be Ds/Dp = 0.79 ± 0.05.
The phase angle on May 4 was 10.9°. It decreased to 10° on May 10
and then increased to 12.8° on May 20. The phase angle bisector
longitude (L_PAB) went from 230° to 237° while the latitude,
B_PAB, went from 5.8° to 9.3°
Observations by Warner at CS3-PDS from 2014 Aug. 9-23 (phase angle
47.7°-38.9°, L_PAB 2°-8°, and B_PAB 5°-3°) showed a large amplitude
lightcurve of 0.79 mag and P = 40.5 h. There were no indications of
the binary nature seen at that time (Warner, 2015; Minor Planet
Bulletin 42, 41-53). However, that data set was considerably sparse
compared to the current one, which makes comparisons of results between
the two somewhat suspect.
Radar observations at Arecibo are planned for early June into August.
Those data should allow a more exact determination of the system
parameters.
(190166) 2005 UP156
B. D. Warner, Center for Solar System Studies-Palmer Divide
Station (CS3-PDS), Landers, CA, USA, and A. W. Harris, MoreData!,
La Cañada, CA, report that CCD photometric observations made
between 2017 May 4 and May 20 show that minor planet (190166)
2005 UP156 is a fully-synchronous binary system with an orbital
period of 40.528 ± 0.0.008 h.
The out-of-eclipse lightcurve shows an amplitude of about 0.4 mag
with eclipse attenuations of 0.53-0.65 mag. The deeper event lasts
about 2.8 hours. The effective secondary-to-primary diameter ratio
is estimated to be Ds/Dp = 0.79 ± 0.05.
The phase angle on May 4 was 10.9°. It decreased to 10° on May 10
and then increased to 12.8° on May 20. The phase angle bisector
longitude (L_PAB) went from 230° to 237° while the latitude,
B_PAB, went from 5.8° to 9.3°
Observations by Warner at CS3-PDS from 2014 Aug. 9-23 (phase angle
47.7°-38.9°, L_PAB 2°-8°, and B_PAB 5°-3°) showed a large amplitude
lightcurve of 0.79 mag and P = 40.5 h. There were no indications of
the binary nature seen at that time (Warner, 2015; Minor Planet
Bulletin 42, 41-53). However, that data set was considerably sparse
compared to the current one, which makes comparisons of results between
the two somewhat suspect.
Radar observations at Arecibo are planned for early June into August.
Those data should allow a more exact determination of the system
parameters.
(190166) 2005 UP156
B. D. Warner, Center for Solar System Studies-Palmer Divide
Station (CS3-PDS), Landers, CA, USA, and A. W. Harris, MoreData!,
La Cañada, CA, report that CCD photometric observations made
between 2017 May 4 and May 20 show that minor planet (190166)
2005 UP156 is a fully-synchronous binary system with an orbital
period of 40.528 ± 0.0.008 h.
B. D. Warner, Center for Solar System Studies-Palmer Divide Station (CS3-PDS), Landers, CA, USA, and A. W. Harris, MoreData!, La Cañada, CA, report that CCD photometric observations made between 2017 May 4 and May 20 show that minor planet (190166) 2005 UP156 is a fully-synchronous binary system with an orbital
period of 40.528 ± 0.0.008 h.
B. D. Warner, Center for Solar System Studies-Palmer Divide Station (CS3-PDS), Landers, CA, USA, and A. W. Harris, MoreData!, La Cañada, CA, report that CCD photometric observations made between 2017 May 4 and May 20 show that minor planet (190166) 2005 UP156 is a fully-synchronous binary system with an orbital period of 40.528 ± 0.0.008 h.
he out-of-eclipse lightcurve shows an amplitude of about 0.4 mag with eclipse attenuations of 0.53-0.65 mag. The deeper event lasts about 2.8 hours. The effective secondary-to-primary diameter ratio is estimated to be Ds/Dp = 0.79 ± 0.05.
The phase angle on May 4 was 10.9°. It decreased to 10° on May 10 and then increased to 12.8° on May 20. The phase angle bisector longitude (L_PAB) went from 230° to 237° while the latitude, B_PAB, went from 5.8° to 9.3°
Observations by Warner at CS3-PDS from 2014 Aug. 9-23 (phase angle 47.7°-38.9°, L_PAB 2°-8°, and B_PAB 5°-3°) showed a large amplitude lightcurve of 0.79 mag and P = 40.5 h. There were no indications of the binary nature seen at that time (Warner, 2015; Minor Planet Bulletin 42, 41-53). However, that data set was considerably sparse compared to the current one, which makes comparisons of results between the two somewhat suspect.
Radar observations at Arecibo are planned for early June into August. Those data should allow a more exact determination of the system parameters.