Physics:Gaia16aye
In astronomy, Gaia16aye is a gravitational microlensing event of the star 2MASS 19400112+3007533 (the source star) by a dimmer binary star system (the lens star system).[1] The source star 2MASS 19400112+3007533 is a magnitude 14.5 (Gaia RP) star in Cygnus. It was closely observed during a set of brightening events caused by gravitational microlensing in 2016.[2] The Gaia16aye event was first noticed by the Gaia space mission via an alert on August 9, 2016.[3][4] The unusual characteristics of the event led to an immediate massive follow-up campaign by tens of professional and amateur observers over the next 500 days, during which 5 brightening events were closely observed.[1] The star brightened up to two and a half magnitudes in each microlensing event over its baseline brightness.
The brightenings were determined to have been caused by a dim binary star system much closer to the Earth, acting as a moving, changing gravitational lens. The light of the lens star system itself was lost in the glare of the brighter star 2MASS 19400112+3007533. The lens star system is predicted to be observable in 2021 after its proper motion has created a separation of about 50 mas from the brighter background star. Detailed observations and analytical modelling determined that the lens system consists of two main sequence stars with Solar masses 0.57 ± 0.05 and 0.36 ± 0.03, at a distance of 780 pc (2,500 ly), and an orbital period of 2.88 years.[5]
The space-time geometry of a binary star system is complicated, which leads to sudden jumps in brightness as the caustics of the lens cross by the light rays from the lensed source.[4] Furthermore, the relative motions of the binary lens stars and the source star interacted with each other:
The rotation was fast enough and the overall micro-lensing event slow enough that the background star entered the high magnification region, left it and then entered it again
See also
- List of stars that have unusual dimming periods
References
- ↑ 1.0 1.1 Staff (21 January 2020). "Global Gaia campaign reveals secrets of stellar pair". European Space Agency. http://www.esa.int/Science_Exploration/Space_Science/Gaia/Global_Gaia_campaign_reveals_secrets_of_stellar_pair. Retrieved 3 February 2020.
- ↑ Starr, Michelle (3 February 2020). "Astronomers Discover 'Invisible' Stars So Dim That We Can't See Them at All" (in en-gb). https://www.sciencealert.com/astronomers-found-a-pair-of-invisible-stars-they-could-lead-us-to-hidden-black-holes.
- ↑ "Gaia spies two temporarily magnified stars" (in en). 2016-10-28. https://www.esa.int/About_Us/ESAC/Gaia_spies_two_temporarily_magnified_stars.
- ↑ 4.0 4.1 "Image of the Week - Follow-Up Opportunity of a Rare Microlensing Event - IoW_20161027 - Gaia - Cosmos". https://www.cosmos.esa.int/web/gaia/IoW_20161027.
- ↑ Wyrzykowski1, L. (21 January 2020). "Full orbital solution for the binary system in the northern Galactic disc microlensing event Gaia16aye⋆". Astronomy & Astrophysics 633 (A98): A98. doi:10.1051/0004-6361/201935097. Bibcode: 2020A&A...633A..98W.
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