국립 천문대의 Kitt Peak 망원경은 이것을 결정하는 데 도움이됩니다.[{” attribute=””>Jupiter-like Planet is the lowest-density gas giant ever detected around a red dwarf.
A gas giant exoplanet with the density of a marshmallow has been detected in orbit around a cool red dwarf star. A suite of astronomical instruments was used to make the observations, including the NASA-funded NEID radial-velocity instrument on the WIYN 3.5-meter Telescope at Kitt Peak National Observatory, a Program of NSF’s NOIRLab. Named TOI-3757 b, the exoplanet is the fluffiest gas giant planet ever discovered around this type of star.
Using the WIYN 3.5-meter Telescope at Kitt Peak National Observatory in Arizona, astronomers have observed an unusual Jupiter-like planet in orbit around a cool red dwarf star. Located in the constellation of Auriga the Charioteer around 580 light-years from Earth, this planet, identified as TOI-3757 b, is the lowest-density planet ever detected around a red dwarf star and is estimated to have an average density akin to that of a marshmallow.
Red dwarf stars are the smallest and dimmest members of so-called main-sequence stars — stars that convert hydrogen into helium in their cores at a steady rate. Although they are “cool” compared to stars like our Sun, red dwarf stars can be extremely active and erupt with powerful flares. This can strip orbiting planets of their atmospheres, making this star system a seemingly inhospitable location to form such a gossamer planet.
Carnegie Institution for Science’s Earth and Planetary Laboratory의 연구원이자 1999년 에 발표된 논문의 첫 번째 저자인 Shubham Kanodia는 점성술 일지에게. 지금까지 이것은 적색 왜성에서 멀리 떨어진 거대한 행성을 발견한 도플러 조사의 작은 표본에서만 볼 수 있었습니다. 지금까지 우리는 가까운 가스 행성을 확실한 방법으로 찾을 만큼 충분히 큰 행성 샘플을 얻지 못했습니다.”
TOI-3757 b를 둘러싼 아직 설명되지 않은 미스터리가 있으며, 그 중 가장 중요한 것은 가스 거대 행성이 적색 왜성, 특히 저밀도 행성 주위에 어떻게 형성될 수 있는지에 대한 것입니다. 그러나 Kanodia 팀은 이 수수께끼에 대한 해결책이 있을 수 있다고 믿습니다.
그들은 TOI-3757 b의 극도로 낮은 밀도가 두 가지 요인의 결과일 수 있다고 제안합니다. 첫 번째는 행성의 암석 핵과 관련이 있습니다. 가스 거인은 지구 질량의 약 10배에 달하는 거대한 암석 코어로 시작하는 것으로 생각되며, 이 지점에서 근처에 있는 많은 양의 가스를 빠르게 끌어당겨 오늘날 우리가 보고 있는 가스 거인을 형성합니다. TOI-3757b는 가스 거인이 있는 다른 M형 왜성보다 중원소의 양이 적으며, 이로 인해 암석 핵이 더 느리게 형성되어 가스 축적 시작이 지연되어 행성의 전체 밀도에 영향을 미쳤을 수 있습니다.
두 번째 요인은 잠정적으로 약간 타원형으로 생각되는 행성의 궤도일 수 있습니다. 다른 때보다 별에 더 가까워지면 과도한 열이 발생하여 행성의 대기가 팽창할 수 있습니다.
외계행성 탐사를 위한 NASA의 위성 ([{” attribute=””>TESS) initially spotted the planet. Kanodia’s team then made follow-up observations using ground-based instruments, including NEID and NESSI (NN-EXPLORE Exoplanet Stellar Speckle Imager), both housed at the WIYN 3.5-meter Telescope; the Habitable-zone Planet Finder (HPF) on the Hobby-Eberly Telescope; and the Red Buttes Observatory (RBO) in Wyoming.
TESS surveyed the crossing of this planet TOI-3757 b in front of its star, which allowed astronomers to calculate the planet’s diameter to be about 150,000 kilometers (100,000 miles) or about just slightly larger than that of Jupiter. The planet finishes one complete orbit around its host star in just 3.5 days, 25 times less than the closest planet in our Solar System — Mercury — which takes about 88 days to do so.
The astronomers then used NEID and HPF to measure the star’s apparent motion along the line of sight, also known as its radial velocity. These measurements provided the planet’s mass, which was calculated to be about one-quarter that of Jupiter, or about 85 times the mass of the Earth. Knowing the size and the mass allowed Kanodia’s team to calculate TOI-3757 b’s average density as being 0.27 grams per cubic centimeter (about 17 grams per cubic feet), which would make it less than half the density of Saturn (the lowest-density planet in the Solar System), about one quarter the density of water (meaning it would float if placed in a giant bathtub filled with water), or in fact, similar in density to a marshmallow.
“Potential future observations of the atmosphere of this planet using NASA’s new James Webb Space Telescope could help shed light on its puffy nature,” says Jessica Libby-Roberts, a postdoctoral researcher at Pennsylvania State University and the second author on this paper.
“Finding more such systems with giant planets — which were once theorized to be extremely rare around red dwarfs — is part of our goal to understand how planets form,” says Kanodia.
The discovery highlights the importance of NEID in its ability to confirm some of the candidate exoplanets currently being discovered by NASA’s TESS mission, providing important targets for the new James Webb Space Telescope (JWST) to follow up on and begin characterizing their atmospheres. This will in turn inform astronomers what the planets are made of and how they formed and, for potentially habitable rocky worlds, whether they might be able to support life.
Reference: “TOI-3757 b: A low-density gas giant orbiting a solar-metallicity M dwarf” by Shubham Kanodia, Jessica Libby-Roberts, Caleb I. Cañas, Joe P. Ninan, Suvrath Mahadevan, Gudmundur Stefansson, Andrea S. J. Lin, Sinclaire Jones, Andrew Monson, Brock A. Parker, Henry A. Kobulnicky, Tera N. Swaby, Luke Powers, Corey Beard, Chad F. Bender, Cullen H. Blake, William D. Cochran, Jiayin Dong, Scott A. Diddams, Connor Fredrick, Arvind F. Gupta, Samuel Halverson, Fred Hearty, Sarah E. Logsdon, Andrew J. Metcalf, Michael W. McElwain, Caroline Morley, Jayadev Rajagopal, Lawrence W. Ramsey, Paul Robertson, Arpita Roy, Christian Schwab, Ryan C. Terrien, John Wisniewski and Jason T. Wright, 5 August 2022, The Astronomical Journal.
DOI: 10.3847/1538-3881/ac7c20
More Stories
Legionnaires는 이 특별한 럭셔리 기능과 연결된 두 개의 별도 크루즈를 타고 출발합니다.
120년의 성장 끝에 일본 대나무가 이제 막 꽃을 피우고 있는 것이 문제다.
SpaceX, 10월 30일 캘리포니아에서 20개의 Starlink 인터넷 위성 발사