1_Gaia@home: 

Calculating longperiod comet orbits
under the simultaneous Galactic and stellar perturbations. (Nbody problem with N of the order of 400). (more details: Królikowska, M and Dybczynski, P.A., 2020: The catalogue of cometary orbits and their dynamical evolution ) 


2_Gaia@home: 
The aim of this work is to investigate the proximity parameters and the influence of the close approach of stars on the basis of Gaia DR2 and DR3. Using a numerical integration in an axisymmetric Galactic model, we determine new parameters of the close encounter for stars. Adding ten thousand clones drawn with the use of a covariance matrix, we estimate the most probable position and velocity of stars at the minimum distance from the Sun. (more details: Berski, F and Dybczynski, P.A., 2020: Close approach parameters recalculated based on the first Gaia data release ) 
Fig.1. The cloud of 13517 clones of the star Gliese 710 drawn according the the covariance matrix taken from the Gaia DR2 catalogue. This cloud is projected onto the maximum scatter plane X'Y', coordinates are expressed in parsecs. The red dot is the Sun position, the green dot is the star nominal position during an encounter and the orange cross is the centroid of the clone cloud. The blue dotted circle shows the approximate extend of the cometary Oort cloud. This star parametrs are known with a good precision so the cloud of clones is rather compact. Fig.2. The cloud of 11327 clones of the star ALS 9243 drawn according the the covariance matrix taken from the Gaia DR2 catalogue. This cloud is projected onto the maximum scatter plane X'Y', coordinates are expressed in parsecs. The red dot is the Sun position, the green dot is the star nominal position during an encounter and the orange cross is the centroid of the clone cloud. The blue dotted circle shows the approximate extend of the cometary Oort cloud. This star parameters have the poor accuracy but the star must be studied in detail since it might have a large mass, even grater than 10 solar masses.Gliese 710 will pass the Sun even closer. 
