Ongoing astrometric microlensing events from VVV and Gaia
| Autor: | Vasily Belokurov, Philip W. Lucas, Leigh C. Smith, N. Wyn Evans, Peter McGill |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Physics
Very Large Telescope Vista Variables in the Via Lactea 010308 nuclear & particles physics FOS: Physical sciences Astronomy and Astrophysics Astrophysics Gravitational microlensing 01 natural sciences Exoplanet Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Hubble space telescope 0103 physical sciences Astrophysics - Instrumentation and Methods for Astrophysics Maxima Instrumentation and Methods for Astrophysics (astro-ph.IM) 010303 astronomy & astrophysics Data release Solar and Stellar Astrophysics (astro-ph.SR) |
| Zdroj: | Monthly Notices of the Royal Astronomical Society: Letters. 487:L7-L12 |
| ISSN: | 1745-3933 1745-3925 |
| DOI: | 10.1093/mnrasl/slz073 |
| Popis: | We extend predictive microlensing event searches using the Vista Variables in the Via Lactea survey and the second Gaia data release. We identify two events with maxima in 2019 that require urgent follow-up. First, we predict that the nearby M2 dwarf L 338-152 will align with a background source with a closest approach of $35^{+35}_{-23}$ mas on 2019 November $16^{+28}_{-27}$ d. This will cause a peak astrometric shift and photometric amplification of the background source of $2.7^{+3.5}_{-1.5}$ mas and $5.6^{+143.2}_{-5.2}$ mmag respectively. This event should be astrometrically detectable by both the Hubble Space Telescope (HST) and the Spectro-Polarimetric High-contrast Exoplanet Research instrument on the Very Large Telescope. Secondly, we predict the likely K dwarf NLTT 45128 will lens a background source with a closest approach of $105.3^{+12.2}_{-11.7}$ mas on 2019 September $26^{+15}_{-15}$ d. This will produce a peak astrometric shift of $0.329^{+0.065}_{-0.059}$ mas. NLTT 45128 is only 3.6 magnitudes brighter than the background source which makes it an excellent candidate for follow-up with HST. Characterisation of these signals will allow direct gravitational masses to be inferred for both L 338-152 and NLTT 45128 with an estimated precision of $\sim9$ and $\sim13$ per cent respectively. 6 pages, 2 figures, accepted MNRAS Letters |
| Databáze: | OpenAIRE |
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