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

Aims: We report the discovery and analysis of a periodic methanol maser inthe massive protostar IRAS 20216+4104. Methods: To obtain the light curve, weused the 6.7 GHz methanol maser spectra collected between 2000-2003 and2009-2023 with the Hartebeesthoek and Torun radio telescopes, as well asspectra from the literature reported prior to 1992. Results: Thevelocity-integrated flux density shows sinusoidal-like variations with a periodof 6.9 +/- 0.03 yr. All but one of the features show periodic changes with arelative amplitude of 2 up to >89. A slightly variable feature displays amoderate anti-correlation between the flux density and the other significantlyvariable features. The maser emission appears to follow the continuum emissionof the red-shifted outflow cavity. A maximum emission of 3.4 and 4.6 mu mprecedes the maser peak by 15 % of the period and the (infrared) IR lightcentroids show time-dependent displacement. The periodic behaviour of the maserand IR emission is likely due to the eclipsing effect from a wobbling innerdisk.

Seven-year periodic variations in the methanol maser line displayed by the massive protostar IRAS 20216+4104