近日，美国北卡罗来纳大学教堂山分校的Madyson G. Barber及其研究团队取得一项新进展。他们观察到一颗巨行星穿过一颗拥有错位盘的300万年原恒星。相关研究成果已于2024年11月20日在国际权威学术期刊《自然》上发表。

该研究团队报道了对凌日行星IRAS 04125+2902b的观测结果，该行星绕金牛座分子云中一颗300万年历史、质量约为太阳0.7倍的预主序星运行。宿主星拥有一个近乎正面朝向（倾角30度）的过渡盘以及一个宽距伴星。

该行星的周期为8.83天，半径为10.7个地球半径（0.96个木星半径），通过径向速度测量得出其质量为90个地球质量，置信上限为95%（0.3个木星质量），使其成为在主序星周围常见的超级地球。和亚海王星的可能前身。

恒星的自转展宽和宽距（4角秒，635天文单位）伴星的轨道均与边缘朝向一致。因此，除了外盘外，该系统的所有组成部分均呈现一致的对齐状态，这种错位现象的成因尚不清楚。

据悉，天文学家已经发现了十多颗绕行年龄为1000万至4000万年恒星的行星，但更年轻的凌日行星仍难以寻觅。这类发现的缺失可能是因为在这个年龄阶段，行星尚未完全形成，或者是因为视线被原行星盘遮挡。然而，人们现在知道，许多外盘是弯曲或破碎的。只要内盘足够稀薄，凌日行星就可能被观测到。

附：英文原文

Title: A giant planet transiting a 3-Myr protostar with a misaligned disk

Author: Barber, Madyson G., Mann, Andrew W., Vanderburg, Andrew, Krolikowski, Daniel, Kraus, Adam, Ansdell, Megan, Pearce, Logan, Mace, Gregory N., Andrews, Sean M., Boyle, Andrew W., Collins, Karen A., De Furio, Matthew, Dragomir, Diana, Espaillat, Catherine, Feinstein, Adina D., Fields, Matthew, Jaffe, Daniel, Lopez Murillo, Ana Isabel, Murgas, Felipe, Newton, Elisabeth R., Palle, Enric, Sawczynec, Erica, Schwarz, Richard P., Thao, Pa Chia, Tofflemire, Benjamin M., Watkins, Cristilyn N., Jenkins, Jon M., Latham, David W., Ricker, George, Seager, Sara, Vanderspek, Roland, Winn, Joshua N., Charbonneau, David, Essack, Zahra, Rodriguez, David R., Shporer, Avi, Twicken, Joseph D., Villaseor, Jesus Noel

Issue&Volume: 2024-11-20

Abstract: Astronomers have found more than a dozen planets transiting stars that are 10–40millionyears old, but younger transiting planets have remained elusive. The lack of such discoveries may be because planets have not fully formed at this age or because our view is blocked by the protoplanetary disk. However, we now know that many outer disks are warped or broken; provided the inner disk is depleted, transiting planets may thus be visible. Here we report observations of the transiting planet IRAS04125+2902b orbiting a 3-million-year-old, 0.7-solar-mass, pre-main-sequence star in the Taurus Molecular Cloud. The host star harbours a nearly face-on (30degrees inclination) transitional disk and a wide binary companion. The planet has a period of 8.83days, a radius of 10.7Earth radii (0.96Jupiter radii) and a 95%-confidence upper limit on its mass of 90Earth masses (0.3Jupiter masses) from radial-velocity measurements, making it a possible precursor of the super-Earths and sub-Neptunes frequently found around main-sequence stars. The rotational broadening of the star and the orbit of the wide (4arcseconds, 635astronomical units) companion are both consistent with edge-on orientations. Thus, all components of the system are consistent with alignment except the outer disk; the origin of this misalignment is unclear.

DOI: 10.1038/s41586-024-08123-3

Source: https://www.nature.com/articles/s41586-024-08123-3