论文标题
来自盖亚任务的白矮人样品的光谱演变的证据
Evidence of Spectral Evolution on the white dwarf sample from the Gaia Mission
论文作者
论文摘要
由于Gaia数据发行2，因此发表了几项作品，描述了观察到的白矮人颜色$ - $幅度图的分叉图，$ \ mbox {$ g _ {\ Mathrm {bp}} $} $} $} - \ mbox {$ g _ {$ g _ {$ g _ {\ mathrm {rp {rp} $ {rp} $} $ 0 $ 0 $ 0。文献中的一些可能的解释包括存在具有不同初始质量功能或两个不同种群的双重人群，一种是由氢$ - $形成的，一种由氦$ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - $ - 信封白矮人形成。我们建议光谱进化来解释分叉。从种群综合方法中，我们发现光谱进化发生在低于$ {\ simeq} 11 \，000 \，\ mathrm {k} $的有效温度中，主要在$ 0.64 \，\ mathrm {m Mathrm {m} _ \ odot $和$ 0.74 \，$ $ $ $ pemrm mathrm} $ pectrip $ 0.64 \，\ mathrm {m}所有的白色矮人。我们还发现Gaia White Dwarf Colour-Magnitude图表明，恒星形成历史记录突然减少了$ 1.4 \，\ Mathrm {gyr} $的物体，并且对于白矮人祖先的最高初始质量功能。
Since the Gaia data release 2, several works were published describing a bifurcation in the observed white dwarf colour$-$magnitude diagram for $\mbox{$G_{\mathrm{BP}}$}-\mbox{$G_{\mathrm{RP}}$} > 0$. Some possible explanations in the literature include the existence of a double population with different initial mass function or two distinct populations, one formed by hydrogen$-$ and one formed by helium$-$envelope white dwarfs. We propose instead spectral evolution to explain the bifurcation. From a population synthesis approach, we find that the spectral evolution occurs for effective temperature below ${\simeq}11\,000\,\mathrm{K}$ and masses mainly between $0.64\,\mathrm{M}_\odot$ and $0.74\,\mathrm{M}_\odot$, which correspond to around $16$ per cent of all DA white dwarfs. We also find the Gaia white dwarf colour-magnitude diagram indicates a star formation history that decreases abruptly for objects younger than $1.4\,\mathrm{Gyr}$ and a top-heavy initial mass function for the white dwarf progenitors.
