Maunakea, Hawaiʻi – One of the youngest planets ever found around a distant infant star has been discovered by an international team of scientists led by University of Hawaiʻi at Mānoa faculty, students, and alumni.
Thousands of planets have been discovered around other stars, but what sets this one apart is that it is newly-formed and can be directly observed. The planet, named 2M0437b, joins a handful of objects advancing our understanding of how planets form and change with time, helping shed new light on the origin of the solar system and Earth.
The in-depth research has been accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available in preprint format on arXiv.org.
“This serendipitous discovery adds to an elite list of planets that we can directly observe with our telescopes,” explained lead author Eric Gaidos, a professor in the UH Mānoa Department of Earth Sciences. “By analyzing the light from this planet we can say something about its composition, and perhaps where and how it formed in a long-vanished disk of gas and dust around its host star.”
The researchers estimate that the planet is a few times more massive than Jupiter, and that it formed with its star several million years ago, around the time the main Hawaiian Islands first emerged above the ocean. The planet is so young that it is still hot from the energy released during its formation, with a temperature similar to the lava erupting from Kīlauea Volcano.
Key Maunakea Telescopes
In 2018, 2M0437b was first seen with the Subaru Telescope on Maunakea by UH Institute for Astronomy (IfA) visiting researcher Teruyuki Hirano. For the past several years, it has been studied carefully utilizing other telescopes on the mauna.
Gaidos and his collaborators used W. M. Keck Observatory on Maunakea to monitor the position of the host star as it moved across the sky. With Keck Observatory’s Near-Infrared Camera, second generation (NIRC2) in combination with the Keck II telescope’s adaptive optics system, the team was able to verify that planet 2M0437b was truly a companion to the star, and not a more distant object. The observations required three years because the star moves slowly across the sky.
“The exquisite data from the Keck Observatory allowed us to confirm that the faint neighbor is moving through space along with its star, and thus is a true companion,” explained Dr. Adam Kraus, a professor in the Department of Astronomy at the University of Texas at Austin and co-author on the paper. “Eventually, we might even be able to measure its orbital motion around the star.”
The planet and its parent star lie in a stellar “nursery” called the Taurus Cloud. 2M0437b is on a much wider orbit than the planets in the solar system; its current separation is about 100 times the Earth-Sun distance, making it easier to observe. However, sophisticated adaptive optics are still needed to compensate for the image distortion caused by Earth’s atmosphere.
“Two of the world’s largest telescopes, adaptive optics technology, and Maunakea’s clear skies were all needed to make this discovery,” said co-author Michael Liu, an astronomer at IfA. “We are all looking forward to more such discoveries, and more detailed studies of such planets with the technologies and telescopes of the future.”
Future Research Potential
Gathering more in-depth research about the newly-discovered planet may not be too far away. “Observations with space telescopes such as NASA’s Hubble and the soon-to-be-launched James Webb Space Telescope could identify gases in its atmosphere and reveal whether the planet has a moon-forming disk,” Gaidos added.
The star that 2M0437b orbits is too faint to be seen with the unaided eye, but currently from Hawaiʻi, the young planet and other infant stars in the Taurus Cloud are almost directly overhead in the pre-dawn hours, north of the bright star Hokuʻula (Aldeberan) and east of the Makaliʻi (Pleiades) star cluster.
ABOUT ADAPTIVE OPTICS
W. M. Keck Observatory is a distinguished leader in the field of adaptive optics (AO), a breakthrough technology that removes the distortions caused by the turbulence in the Earth’s atmosphere. Keck Observatory pioneered the astronomical use of both natural guide star (NGS) and laser guide star adaptive optics (LGS AO) and current systems now deliver images three to four times sharper than the Hubble Space Telescope at near-infrared wavelengths. AO has imaged the four massive planets orbiting the star HR8799, measured the mass of the giant black hole at the center of our Milky Way Galaxy, discovered new supernovae in distant galaxies, and identified the specific stars that were their progenitors. Support for this technology was generously provided by the Bob and Renee Parsons Foundation, Change Happens Foundation, Gordon and Betty Moore Foundation, Mt. Cuba Astronomical Foundation, NASA, NSF, and W. M. Keck Foundation.
The Near-Infrared Camera, second generation (NIRC2) works in combination with the Keck II adaptive optics system to obtain very sharp images at near-infrared wavelengths, achieving spatial resolutions comparable to or better than those achieved by the Hubble Space Telescope at optical wavelengths. NIRC2 is probably best known for helping to provide definitive proof of a central massive black hole at the center of our galaxy. Astronomers also use NIRC2 to map surface features of solar system bodies, detect planets orbiting other stars, and study detailed morphology of distant galaxies.
ABOUT W. M. KECK OBSERVATORY
The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two 10-meter optical/infrared telescopes atop Maunakea on the Island of Hawaiʻi feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.