Evidence for the volatile-rich composition of a 1.5-Earth-radius planet
نویسندگان
چکیده
The population of planets smaller than approximately 1.7 Earth radii (R⊕) is widely interpreted as consisting rocky worlds, generally referred to super-Earths. This picture largely corroborated by radial velocity mass measurements for close-in super-Earths but lacks constraints at lower insolations. Here we present the results a detailed study Kepler-138 system using 13 Hubble and Spitzer transit observations warm-temperate 1.51 ± 0.04 R⊕ planet d ( $${T}_{\rm{eq,A_{\rm{B}} = 0.3}}\approx 350\,{\mathrm{K}}$$ ) combined with new its host star obtained Keck/High Resolution Echelle Spectrometer. We find evidence volatile-rich ‘water world’ nature d, large fraction $M_{\rm{d}}$ contained in thick volatile layer. finding independently supported timing variations $${M}_{{{{\rm{d}}}}}=2.{1}_{-0.7}^{+0.6}\,{M}_{\oplus }$$ ), well flat optical/infrared transmission spectrum. Quantitatively, infer composition $$1{1}_{-4}^{+3}\%$$ volatiles or ~51% volume, 2,000-km-deep water mantle atmosphere on top core an Earth-like silicates/iron ratio. Any hypothetical hydrogen layer consistent (<0.003 M⊕) would have swiftly been lost ~10 Myr timescale. bulk therefore resembles those icy moons, rather terrestrial planets, Solar System. conclude that not all are worlds exist overlapping size regime, especially Finally, our photodynamical analysis also reveals c (with Rc $${M}_{{{{\rm{c}}}}}=2.{3}_{-0.5}^{+0.6}\,{M}_{\oplus slightly warmer twin (that is, another world same system) presence e, likely non-transiting inner edge habitable zone. A comprehensive fourth planet. Remarkably, probably composed 50% indicative world, despite small ~1.5 size.
منابع مشابه
Volatile-Rich Earth-Mass Planets in the Habitable Zone
Planets that form beyond the snow line with too little mass to seed rapid gas accretion (. 10 M⊕) should be rich in volatile ices like H2O and NH3. Some of these planets should migrate inward by interacting with a circumstellar disk or with other planets. Such objects can retain their volatiles for billions of years or longer at ∼ 1 AU as their atmospheres undergo slow hydrodynamic escape. Thes...
متن کاملinvestigating the feasibility of a proposed model for geometric design of deployable arch structures
deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...
Infrared Radius for the Transiting Extrasolar Planet
We have measured the infrared transit of the extrasolar planet HD209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 μm array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after t...
متن کاملA Spitzer 1 Infrared Radius for the Transiting Extrasolar Planet
We have measured the infrared transit of the extrasolar planet HD209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 μm array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature Astronomy
سال: 2022
ISSN: ['2397-3366']
DOI: https://doi.org/10.1038/s41550-022-01835-4