NGTS-8b and NGTS-9b: two non-inflated hot-Jupiters
NGTS-8b and NGTS-9b: two non-inflated hot-Jupiters
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DOI：
10.1093/mnras/stz3140
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发表时间：
2019-11
影响因子：
4.8
通讯作者：
J. Costes;C. Watson;C. Belardi;I. Braker;M. Burleigh;S. Casewell;P. Eigmüller;M. Günther;J. Ja
中科院分区：
文献类型：
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作者：
J. Costes;C. Watson;C. Belardi;I. Braker;M. Burleigh;S. Casewell;P. Eigmüller;M. Günther;J. Ja
我们报告下一代凌日巡天（NGTS）发现了两颗热木星NGTS-8b和NGTS-9b。它们分别绕$V\, =\, 13.68$ K0V恒星（Teff = 5241±50 K）运行，周期为2.49970天，和$V\, =\, 12.80$ F8V恒星（Teff = 6330±130 K）运行，周期为4.43527天。通过SAAO 1.0 m和欧拉望远镜的后续光度观测，我们独立地验证了这些凌日现象，并使用HARPS， FEROS和CORALIE径向速度报告了行星参数。NGTS-8b的质量为$0.93\,^{+0.04}_{-0.03}$ MJ，半径为1.09±0.03 RJ，与木星相似，因此密度为$0.89\,^{+0.08}_{-0.07}$ g cm - 3。这与NGTS-9b形成了对比，后者的质量为2.90±0.17 MJ，半径为1.07±0.06 RJ，密度为2.93^{+0.53}_{-0.49}$ g cm−3。从统计学上讲，行星参数使这两个天体的半径都比预测的要大。然而，我们发现它们的半径与理论非膨胀模型的预测一致。
We report the discovery, by the Next Generation Transit Survey (NGTS), of two hot-Jupiters NGTS-8b and NGTS-9b. These orbit a $V\, =\, 13.68$ K0V star (Teff = 5241 ± 50 K) with a period of 2.49970 days, and a $V\, =\, 12.80$ F8V star (Teff = 6330 ± 130 K) in 4.43527 days, respectively. The transits were independently verified by follow-up photometric observations with the SAAO 1.0-m and Euler telescopes, and we report on the planetary parameters using HARPS, FEROS and CORALIE radial velocities. NGTS-8b has a mass, $0.93\, ^{+0.04}_{-0.03}$ MJ and a radius, 1.09 ± 0.03 RJ similar to Jupiter, resulting in a density of $0.89\, ^{+0.08}_{-0.07}$ g cm−3. This is in contrast to NGTS-9b, which has a mass of 2.90 ± 0.17 MJ and a radius of 1.07 ± 0.06 RJ, resulting in a much greater density of $2.93^{+0.53}_{-0.49}$ g cm−3. Statistically, the planetary parameters put both objects in the regime where they would be expected to exhibit larger than predicted radii. However, we find that their radii are in agreement with predictions by theoretical non-inflated models.