Searching sub-stellar objects in DR1-TGAS, effectiveness and efficiency of Gaias' astrometry

TL;DR

This paper evaluates Gaia DR1-TGAS data's capability to detect sub-stellar objects, finding current accuracy insufficient but providing estimates for future improvements needed for detection.

Contribution

It analyzes Gaia DR1-TGAS data to determine the accuracy required for detecting sub-stellar objects and assesses Gaia's potential effectiveness in future data releases.

Findings

DR1 data insufficient for most sub-stellar detections

Detection possible for jovian and larger objects with long orbital periods

Provides minimum astrometric angle thresholds for detection

Abstract

We used 1,477,047 data from DR1-TGAS, in order to analyse the minimum require- ments of accuracy, necessary to detect sub-stellar objects in the astrometric mea- surements of Gaia. We found that the first set of data (DR1) does not have enough accuracy, so sub-stellar objects can not be easily detected. Barely, it would be possible to detect jovian and higher mass objects, with orbital periods over 5 years. We made the calculations of the minimum values of the astrometric angle produced by an or- biting sub-stellar object using a range of different masses. We estimate the efficiency and effectiveness of the DR1-TGAS data in order to detect sub-stellar objects and the minimum accuracy that Gaia would be required to detect these objects using the datasets that the mission will release in the near future.