English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Observations offormaldehyde (H2CO) have been conducted toward comets C/1995 O1 (Hale-Bopp), C/2001 Q4 (NEAT), and C/2002 T7 (LINEAR) using the Arizona Radio Observatory (ARO) 12 m telescope at 1.2 and 2 mm. Aperture synthesis maps of H2CO at 3 mm were made using the Berkeley-Illinois-Maryland Association (BIMA) interferometer toward comet Hale-Bopp. These data indicate that the production rate of H2CO is  3:7 ; 10 28 s  1 at  1 AU in comet Hale-Bopp, using a simple Monte Carlo model, if a nuclear origin for the molecule is assumed. However, maps of H2CO in Hale-Bopp, in comparison with CO, show an extended distribution (rs  15,000 km) with small-scale structure oriented roughly along the comet-Sun direction. This result suggests a source of H2CO other than the comet nucleus. The extended source of formaldehyde is probably grains composed of a mixture of silicates and organicmaterial.Theproductionrate forH2CO increasestoQ  1:4 ; 10 29 s  1 assuming suchanextended grain source. This value implies a Q/Q(H2O)  1:4%, which is similar to the production rate ratio of Q/Q(H2O)  4% derived from in situ measurements of H2CO in comet Halley. Production rates for H2CO toward comets C/2002 T7 (LINEAR) and C/2001 Q4 (NEAT) are 1:4 ; 10 27 and 5:6 ; 10 26 s  1 , respectively, modeled using the extended grain source. The spectra of H2CO measured toward comet C/2002 T7 (LINEAR) show evidence for a second velocity component, most likely arising from comet fragmentation. Subject headingg astrobiology — comets: individual (Hale-Bopp (C/1995 O1), NEAT (C/2001 Q4), LINEAR (C/2002 T7)) — radio lines: solar system — techniques: interferometric

Formaldehyde in Comets C/1995 O1 (Hale‐Bopp), C/2002 T7 (LINEAR), and C/2001 Q4 (NEAT): Investigating the Cometary Origin of H2CO

Formaldehyde in Comets C/1995 O1 (Hale‐Bopp), C/2002 T7 (LINEAR), and C/2001 Q4 (NEAT): Investigating the Cometary Origin of H₂CO