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Table 3.
Constraints that need to be satisfied in order for a GDR2 object with a 2-parameter astrometric solution to be selected as a source star.
| GDR2 column name | Relation | Value | Unit | Description |
|---|---|---|---|---|
| DUPLICATED_SOURCE | = | FALSE | – | Reject duplicated objects that are likely to have astrometric and photometric problems. |
| ASTROMETRIC_PARAMS_SOLVED | = | 3 | – | Only accept objects that have a 2-parameter astrometric solution. |
| VISIBILITY_PERIODS_USED | ≥ | 5 | – | Reject objects with too few independent groups of observations (at least 4 days between each group). |
|
< | 1.2 max{1.5,exp[0.2 (19.5−G)]} | – | Reject objects with a spurious astrometric solution. |
| ASTROMETRIC_EXCESS_NOISE_SIG | < | 4 | – | Reject objects with significant excess noise in the astrometric solution. |
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