%0 Generic %1 hwang2020nonmonotonic %A Hwang, Hsiang-Chih %A Ting, Yuan-Sen %A Schlaufman, Kevin C. %A Zakamska, Nadia L. %A Wyse, Rosemary F. G. %D 2020 %K metallicity multiplicity %T The non-monotonic, strong metallicity dependence of the wide-binary fraction %U http://arxiv.org/abs/2010.02920 %X The metallicity dependence of the wide-binary fraction in stellar populations plays a critical role in resolving the open question of wide binary formation. In this paper, we investigate the metallicity (Fe/H) and age dependence of the wide-binary fraction (binary separations between $10^3$ and $10^4$ AU) for field F and G dwarfs within 500 pc by combining their metallicity and radial velocity measurements from LAMOST DR5 with the astrometric information from Gaia DR2. We show that the wide-binary fraction strongly depends on the metallicity: as metallicity increases, the wide-binary fraction first increases, peaks at Fe/H$0$, and then decreases at the high metallicity end. The wide-binary fraction at Fe/H$=0$ is about two times larger than that at Fe/H$=-1$ and Fe/H$+0.5$. This metallicity dependence is dominated by the thin-disk stars. Using stellar kinematics as a proxy of stellar age, we show that younger stars have a higher wide-binary fraction. We propose that multiple formation channels are responsible for the metallicity and age dependence. In particular, the positive metallicity correlation at Fe/H$<0$ and the age dependence may be due to the denser formation environments and higher-mass clusters at earlier times. The negative metallicity correlation at Fe/H$>0$ can be inherited from the similar metallicity dependence of close binaries, although we cannot rule out the possibility that radial migration may play a role in enhancing the wide-binary fraction around the solar metallicity.

@misc{hwang2020nonmonotonic, abstract = {The metallicity dependence of the wide-binary fraction in stellar populations plays a critical role in resolving the open question of wide binary formation. In this paper, we investigate the metallicity ([Fe/H]) and age dependence of the wide-binary fraction (binary separations between $10^3$ and $10^4$ AU) for field F and G dwarfs within 500 pc by combining their metallicity and radial velocity measurements from LAMOST DR5 with the astrometric information from Gaia DR2. We show that the wide-binary fraction strongly depends on the metallicity: as metallicity increases, the wide-binary fraction first increases, peaks at [Fe/H]$\simeq 0$, and then decreases at the high metallicity end. The wide-binary fraction at [Fe/H]$=0$ is about two times larger than that at [Fe/H]$=-1$ and [Fe/H]$\simeq +0.5$. This metallicity dependence is dominated by the thin-disk stars. Using stellar kinematics as a proxy of stellar age, we show that younger stars have a higher wide-binary fraction. We propose that multiple formation channels are responsible for the metallicity and age dependence. In particular, the positive metallicity correlation at [Fe/H]$<0$ and the age dependence may be due to the denser formation environments and higher-mass clusters at earlier times. The negative metallicity correlation at [Fe/H]$>0$ can be inherited from the similar metallicity dependence of close binaries, although we cannot rule out the possibility that radial migration may play a role in enhancing the wide-binary fraction around the solar metallicity.}, added-at = {2020-10-07T15:38:58.000+0200}, author = {Hwang, Hsiang-Chih and Ting, Yuan-Sen and Schlaufman, Kevin C. and Zakamska, Nadia L. and Wyse, Rosemary F. G.}, biburl = {https://www.bibsonomy.org/bibtex/239b2e6fb1c93dfa03fcdd0210ee82bc0/superjenwinters}, description = {The non-monotonic, strong metallicity dependence of the wide-binary fraction}, interhash = {1f9274bd874d6fe89ef7c8076213bdca}, intrahash = {39b2e6fb1c93dfa03fcdd0210ee82bc0}, keywords = {metallicity multiplicity}, note = {cite arxiv:2010.02920Comment: Submitted to MNRAS. Fig 2 and 6 are the key results}, timestamp = {2020-10-07T15:38:58.000+0200}, title = {The non-monotonic, strong metallicity dependence of the wide-binary fraction}, url = {http://arxiv.org/abs/2010.02920}, year = 2020 }