Only in a limited number of cases the observations supply complete information on the spin vectors of asteroids. A complex analysis is required to compute the orientation (latitude and longitude) of poles, and often multiple solutions and strong discrepancies among the outcomes of different methods are present. The spin vector catalog, maintained at Poznan observatory, lists the available (presently less than 200, and not always unambiguous) pole data.The statistical analysis of the data, published in 2007, is now becoming obsolete, due to a significant growth of the database. In the present paper we update the analysis, confirming several features already highlighted by the previous paper, and finding some new results.In particular, the excess of prograde vs. retrograde Main Belt asteroids is now significant for all cataloged bodies smaller than 100 km. The rarity of poles close to the ecliptic plane, resulting from the previous analysis, but recently questioned, is confirmed, with a fundamental contribution of bodies smaller than 40 km.Only after a future - both qualitative and quantitative - improvement of the database, such as that expected to come out from forthcoming space missions, such as GAIA, we will be able to obtain a statistically robust scenario, hopefully free from possible relevant selection effects.
Spin vectors of asteroids: Updated statistical properties and open problems
PAOLICCHI, PAOLO;
2012-01-01
Abstract
Only in a limited number of cases the observations supply complete information on the spin vectors of asteroids. A complex analysis is required to compute the orientation (latitude and longitude) of poles, and often multiple solutions and strong discrepancies among the outcomes of different methods are present. The spin vector catalog, maintained at Poznan observatory, lists the available (presently less than 200, and not always unambiguous) pole data.The statistical analysis of the data, published in 2007, is now becoming obsolete, due to a significant growth of the database. In the present paper we update the analysis, confirming several features already highlighted by the previous paper, and finding some new results.In particular, the excess of prograde vs. retrograde Main Belt asteroids is now significant for all cataloged bodies smaller than 100 km. The rarity of poles close to the ecliptic plane, resulting from the previous analysis, but recently questioned, is confirmed, with a fundamental contribution of bodies smaller than 40 km.Only after a future - both qualitative and quantitative - improvement of the database, such as that expected to come out from forthcoming space missions, such as GAIA, we will be able to obtain a statistically robust scenario, hopefully free from possible relevant selection effects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
