Chemical evolution. XIV. Oxidation of diaminomaleonitrile and its possible role in hydrogen cyanide oligomerization

1973 ◽  
Vol 38 (19) ◽  
pp. 3302-3307 ◽  
Author(s):  
J. P. Ferris ◽  
T. J. Ryan
Keyword(s):  
Chemical Evolution ◽  
Hydrogen Cyanide

scholarly journals HYDROGEN CYANIDE DIMER AND CHEMICAL EVOLUTION

1962 ◽  
Vol 48 (8) ◽  
pp. 1300-1306 ◽  
Author(s):  
R. M. Kliss ◽  
C. N. Matthews
Keyword(s):  
Chemical Evolution ◽  
Hydrogen Cyanide

Chemical evolution XXIX. Pyrimidines from hydrogen cyanide

Biosystems ◽  
1977 ◽  
Vol 9 (2-3) ◽  
pp. 81-86 ◽  
Author(s):  
J.P. Ferris ◽  
P.C. Joshi ◽  
J.G. Lawless
Keyword(s):  
Chemical Evolution ◽  
Hydrogen Cyanide

Radiolysis of aqueous solutions of hydrogen cyanide (pH∼6): Compounds of interest in chemical evolution studies

1983 ◽  
Vol 19 (2) ◽  
pp. 184-191 ◽  
Author(s):  
V. Niketić ◽  
Z. D. Draganić ◽  
S. Nešković ◽  
S. Jovanović ◽  
I. G. Draganić
Keyword(s):  
Aqueous Solutions ◽  
Chemical Evolution ◽  
Hydrogen Cyanide

scholarly journals Inferring Shallow Surfaces on Sub-Neptune Exoplanets with JWST

2021 ◽  
Vol 922 (2) ◽  
pp. L27
Author(s):  
Shang-Min Tsai ◽  
Hamish Innes ◽  
Tim Lichtenberg ◽  
Jake Taylor ◽  
Matej Malik ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Chemical Evolution ◽  
Equatorial Plane ◽  
Hydrogen Cyanide ◽  
Trace Gases ◽  
Composition Distribution ◽  
Photochemical Model ◽  
James Webb Space Telescope ◽  
Nitrogen Conversion ◽  
Uniform Composition

Abstract Planets smaller than Neptune and larger than Earth make up the majority of the discovered exoplanets. Those with H2-rich atmospheres are prime targets for atmospheric characterization. The transition between the two main classes, super-Earths and sub-Neptunes, is not clearly understood as the rocky surface is likely not accessible to observations. Tracking several trace gases (specifically the loss of ammonia (NH3) and hydrogen cyanide (HCN)) has been proposed as a proxy for the presence of a shallow surface. In this work, we revisit the proposed mechanism of nitrogen conversion in detail and find its timescale on the order of a million years. NH3 exhibits dual paths converting to N2 or HCN, depending on the UV radiation of the star and the stage of the system. In addition, methanol (CH3OH) is identified as a robust and complementary proxy for a shallow surface. We follow the fiducial example of K2-18b with a 2D photochemical model on an equatorial plane. We find a fairly uniform composition distribution below 0.1 mbar controlled by the dayside, as a result of slow chemical evolution. NH3 and CH3OH are concluded to be the most unambiguous proxies to infer surfaces on sub-Neptunes in the era of the James Webb Space Telescope.

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