Main belt asteroids ( 6070 ) Rheinland and ( 54827 ) 2001 NQ8 belong to a small population of couples of bodies which reside on very similar heliocentric orbits .
Vokrouhlický & Nesvorný ( 2008 , AJ 136 , 280 ) promoted a term “ asteroid pairs ” , pointing out their common origin within the past tens to hundreds of ky .
Previous attempts to reconstruct the initial configuration of Rheinland and 2001 NQ8 at the time of their separation have led to the prediction that Rheinland ’ s rotation should be retrograde .
Here we report extensive photometric observations of this asteroid and use the lightcurve inversion technique to directly determine its rotation state and shape .
We confirm the retrograde sense of rotation of Rheinland , with obliquity value constrained to be \geq 140 ^ { \circ } .
The ecliptic longitude of the pole position is not well constrained as yet .
The asymmetric behavior of Rheinland ’ s lightcurve reflects a sharp , near-planar edge in our convex shape representation of this asteroid .
Our calibrated observations in the red filter also allow us to determine H _ { R } = 13.68 \pm 0.05 and G = 0.31 \pm 0.05 values of the H-G system .
With the characteristic color index V - R = 0.49 \pm 0.05 for the S-type asteroids , we thus obtain H = 14.17 \pm 0.07 for the absolute magnitude of ( 6070 ) Rheinland .
This a significantly larger value than previously obtained from analysis of the astrometric survey observations .
We next use the obliquity constraint for Rheinland to eliminate some degree of uncertainty in the past propagation of its orbit .
This is because the sign of the past secular change of its semimajor axis due to the Yarkovsky effect is now constrained .
Determination of the rotation state of the secondary component , asteroid ( 54827 ) 2001 NQ8 , is the key element in further constraining the age of the pair and its formation process .