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 Tools annual

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 Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We show that `Oumuamua's excited spin could be in a high energy LAM state,which implies that its shape could be far from the highly elongated shape foundin previous studies. CLEAN and ANOVA algorithms are used to analyze `Oumuamua'slightcurve using 818 observations over 29.3~days. Two fundamental periodicitiesare found at frequencies (2.77$\pm$0.11) and (6.42$\pm$0.18)~cycles/day,corresponding to (8.67$\pm$0.34)~h and (3.74$\pm$0.11)~h, respectively. Thephased data show that the lightcurve does not repeat in a simple manner, butapproximately shows a double minimum at 2.77~cycles/day and a single minimum at6.42~cycles/day. This is characteristic of an excited spin state. `Oumuamuacould be spinning in either the long (LAM) or short (SAM) axis mode. For both,the long axis precesses around the total angular momentum vector with anaverage period of (8.67$\pm$0.34)~h. For the three LAMs we have found, thepossible rotation periods around the long axis are 6.58, 13.15, or 54.48~h,with 54.48~h being the most likely. `Oumuamua may also be nutating withrespective periods of half of these values. We have also found two possible SAMstates where `Oumuamua oscillates around the long axis with possible periods at13.15 and 54.48~h, the latter as the most likely. In this case any nutationwill occur with the same periods. Determination of the spin state, theamplitude of the nutation, the direction of the TAMV, and the average totalspin period may be possible with a direct model fit to the lightcurve. We findthat `Oumuamua is "cigar-shaped"', if close to its lowest rotational energy,and an extremely oblate spheroid if close to its highest energy state for itstotal angular momentum.

The Excited Spin State of 1I/2017 U1 `Oumuamua