Zobrazeno 1 - 10
of 254
pro vyhledávání: '"Isotopic abundances"'
Publikováno v:
The Astrophysical Journal Letters, Vol 977, Iss 1, p L24 (2024)
Presolar grains are stardust particles that condensed in the ejecta or in the outflows of dying stars and can today be extracted from meteorites. They recorded the nucleosynthetic fingerprint of their parent stars and thus serve as valuable probes of
Externí odkaz:
https://doaj.org/article/35118008316d497bbd0f37f1308733ad
Publikováno v:
The Astrophysical Journal Letters, Vol 975, Iss 1, p L16 (2024)
Angrites originate from the early-formed differentiated angrite parent body. The pristine volcanic angrite D’Orbigny is devoid of brecciation, shock effects, or any evidence of secondary processes and is thus key for studying the early stages of pl
Externí odkaz:
https://doaj.org/article/d344dbe1d598473b8853dd4911e6f55b
Autor:
Parashmoni Kashyap, Liton Majumdar, Anne Dutrey, Stéphane Guilloteau, Karen Willacy, Edwige Chapillon, Richard Teague, Dmitry Semenov, Thomas Henning, Neal Turner, Raghvendra Sahai, Ágnes Kóspál, Audrey Coutens, V. Piétu, Pierre Gratier, Maxime Ruaud, N. T. Phuong, E. Di Folco, Chin-Fei Lee, Y.-W. Tang
Publikováno v:
The Astrophysical Journal, Vol 976, Iss 2, p 258 (2024)
Resolved molecular line observations are essential for gaining insight into the physical and chemical structure of protoplanetary disks, particularly in cold, dense regions where planets form and acquire their chemical compositions. However, tracing
Externí odkaz:
https://doaj.org/article/286067b65f51483daee57c35d4713c81
Autor:
Alice S. Booth, Maria N. Drozdovskaya, Milou Temmink, Hideko Nomura, Ewine F. van Dishoeck, Luke Keyte, Charles J. Law, Margot Leemker, Nienke van der Marel, Shota Notsu, Karin Öberg, Catherine Walsh
Publikováno v:
The Astrophysical Journal, Vol 975, Iss 1, p 72 (2024)
Stable isotopic ratios constitute powerful tools for unraveling the thermal and irradiation history of volatiles. In particular, we can use our knowledge of the isotopic fractionation processes active during the various stages of star, disk, and plan
Externí odkaz:
https://doaj.org/article/e2f71c1493b9448690e7b26bc8a15bc7
Autor:
Ziyi Guo, Zhi-Yu Zhang, Zhiqiang Yan, Eda Gjergo, Allison W. S. Man, R. J. Ivison, Xiaoting Fu, Yong Shi
Publikováno v:
The Astrophysical Journal, Vol 970, Iss 2, p 136 (2024)
Recent observations and theories have presented a strong challenge to the universality of the stellar initial mass function (IMF) in extreme environments. A notable example has been found for starburst conditions, where evidence favors a top-heavy IM
Externí odkaz:
https://doaj.org/article/c3001e130ac44f439876c75a19e883e0
Autor:
Tomohiro C. Yoshida, Hideko Nomura, Kenji Furuya, Richard Teague, Charles J. Law, Takashi Tsukagoshi, Seokho Lee, Christian Rab, Karin I. Öberg, Ryan A. Loomis
Publikováno v:
The Astrophysical Journal, Vol 966, Iss 1, p 63 (2024)
Recent measurements of carbon isotope ratios in both protoplanetary disks and exoplanet atmospheres have suggested a possible transfer of significant carbon isotope fractionation from disks to planets. For a clearer understanding of the isotopic link
Externí odkaz:
https://doaj.org/article/09455a1a183c4a9988f9f3f3f97c2fa2
Publikováno v:
The Astrophysical Journal, Vol 966, Iss 1, p 11 (2024)
The elemental abundances between strontium and silver ( Z = 38–47) observed in the atmospheres of very metal-poor stars in the Galaxy may contain the fingerprint of the weak r -process and ν p -process occurring in early core-collapse supernovae e
Externí odkaz:
https://doaj.org/article/db4c8797bc7f4473954657742c7630c6
Autor:
N. D. Nevill, P. A. Bland, D. W. Saxey, W. D. A. Rickard, P. Guagliardo, N. E. Timms, L. V. Forman, L. Daly, S. M. Reddy
Publikováno v:
The Astrophysical Journal, Vol 964, Iss 2, p 151 (2024)
We have discovered a presolar olivine from ALH 77307 with the highest ^25 Mg isotopic composition measured in a silicate to date ( δ ^25 Mg = 3025.1‰ ± 38.3‰). Its isotopic compositions challenge current stellar models, with modeling of magnesi
Externí odkaz:
https://doaj.org/article/afd77b28cfff4e20b32fa4a794ed4cec
Autor:
Kevin Zahnle
Publikováno v:
The Planetary Science Journal, Vol 5, Iss 3, p 73 (2024)
Noble gases provide tracers of cosmic provenance that are accessible to a future Uranus atmospheric probe. Argon and krypton are expected to be well mixed on Uranus with respect to H _2 and He, although condensation at the winter pole may be possible
Externí odkaz:
https://doaj.org/article/58520a5392de49fc85d9fccbe22f42ad
Autor:
Jerry W. Xuan, Jason Wang, Luke Finnerty, Katelyn Horstman, Simon Grimm, Anne E. Peck, Eric Nielsen, Heather A. Knutson, Dimitri Mawet, Howard Isaacson, Andrew W. Howard, Michael C. Liu, Sam Walker, Mark W. Phillips, Geoffrey A. Blake, Jean-Baptiste Ruffio, Yapeng Zhang, Julie Inglis, Nicole L. Wallack, Aniket Sanghi, Erica J. Gonzales, Fei Dai, Ashley Baker, Randall Bartos, Charlotte Z. Bond, Marta L. Bryan, Benjamin Calvin, Sylvain Cetre, Jacques-Robert Delorme, Greg Doppmann, Daniel Echeverri, Michael P. Fitzgerald, Nemanja Jovanovic, Joshua Liberman, Ronald A. López, Emily C. Martin, Evan Morris, Jacklyn Pezzato, Garreth Ruane, Ben Sappey, Tobias Schofield, Andrew Skemer, Taylor Venenciano, J. Kent Wallace, Ji Wang, Peter Wizinowich, Yinzi Xin, Shubh Agrawal, Clarissa R. Do Ó, Chih-Chun Hsu, Caprice L. Phillips
Publikováno v:
The Astrophysical Journal, Vol 962, Iss 1, p 10 (2024)
M dwarfs are common host stars to exoplanets but often lack atmospheric abundance measurements. Late-M dwarfs are also good analogs to the youngest substellar companions, which share similar T _eff ∼ 2300–2800 K. We present atmospheric analyses f
Externí odkaz:
https://doaj.org/article/1d532df8b3dd453999dd5def32caedb8