论文标题
黑洞X射线二进制Maxi J1820+070的供体
The Donor of the Black-Hole X-Ray Binary MAXI J1820+070
论文作者
论文摘要
我们估计积聚黑洞二进制Maxi J1820+070的捐助者的参数。轨道倾斜度上二进制周期，旋转和径向速度和约束的测量值表示供体是一个子巨头，质量为$ m_2 \ of $ m_2 \ of 0.49^{+0.10} _ { - 0.10} _ { - 0.10} m_ \ odot $，半径为$ r_2 \ of $ r_2 \ of $ r_2 \ of $ r_2 \ of $ r_2 \ of $ r_2 \ of。 1.19^{+0.08} _ { - 0.08} r_ \ odot $。我们重新分析了先前从Gran Telescopio Canarias获得的先前获得的光谱，并发现它对$ t> 4200 $ K的有效温度严格下限。我们编译了该系统静止期间观察到的光学和红外通量。从Pan-Stars1数据中发现的Minima $ r $和$ i $ band Fluxes版本2释放前发现前成像，并且距离为$ d \ 3 $ kpc，$ e（b $ - $ v）= 0.23 $和$ r_2 $ reddening of $ e（b $ v）和$ r_2 \ liff lime lime lime lime lim lime lime $ t \ lime lime lime lime lime to $ 4230。对于较大的距离，温度可以更高，高达约4500 K（对应于先前研究的K5光谱类型），$ d = 3.5 $ kpc，gaia barallax允许。我们对二进制系统执行进化计算，并将其与观察性约束进行比较。我们的模型将上述温度和半径约束拟合在$ d \ 3 $ kpc的质量为40万美元\ odot $，$ t \ od4200 $ k和太阳金属性。两种替代型号需要$ d \ gtrsim 3.3 $ - 3.4 kpc，$ 0.4 m_ \ odot $，$ t \ od4500 $ k和一半太阳能金属，$ 550万美元\ odot $，$ t \ od4300 $ k和Solar Metallicity。这些模型产生$ \ sim \！\！\！10^{ - 10} m_ \ odot $/yr的传质速率，与基于估计的积聚质量$ \！2 \！2 \ times 10^{25} $ G的质量兼容，以及2018年发现与1934年的历史爆发之间的时间。
We estimate the parameters of the donor of the accreting black-hole binary MAXI J1820+070. The measured values of the binary period, rotational and radial velocities and constraints on the orbital inclination imply the donor is a subgiant with the mass of $M_2\approx 0.49^{+0.10}_{-0.10}M_\odot$ and the radius of $R_2\approx 1.19^{+0.08}_{-0.08}R_\odot$. We re-analyze the previously obtained optical spectrum from the Gran Telescopio Canarias, and found it yields a strict lower limit on the effective temperature of $T>4200$ K. We compile optical and infrared fluxes observed during the quiescence of this system. From the minima $r$ and $i$-band fluxes found in Pan-STARSS1 Data Release 2 pre-discovery imaging and for a distance of $D\approx3$ kpc, reddening of $E(B$--$V)=0.23$ and $R_2\approx{1.11R_\odot}$, we find $T\lesssim4230$ K, very close to the above lower limit. For a larger distance, the temperature can be higher, up to about 4500 K (corresponding to a K5 spectral type, preferred by previous studies) at $D=3.5$ kpc, allowed by the Gaia parallax. We perform evolutionary calculations for the binary system and compare them to the observational constraints. Our model fitting the above temperature and radius constraints at $D\approx 3$ kpc has the mass of $0.4M_\odot$, $T\approx4200$ K and solar metallicity. Two alternative models require $D\gtrsim 3.3$--3.4 kpc at $0.4 M_\odot$, $T\approx4500$ K and half solar metallicity, and $0.5M_\odot$, $T\approx4300$ K and solar metallicity. These models yield mass transfer rates of $\sim\!\!10^{-10}M_\odot$/yr, compatible with those based on the estimated accreted mass of $\approx\!2\times 10^{25}$ g and the time between the 2018 discovery and the 1934 historical outburst.
