Long-term monitoring of comet 29P/Schwassmann-Wachmann 1 from Lulin observatory
Authors: Lin Zhong-Yi 
Published: September 2022

&lt;div class=&quot;textLayer&quot;&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;Multi-band photometric monitoring of comet 29P/Schwassmann-Wachmann 1 was &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;conducted on the standard Johnson-Cousins filter set, and the observations were &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;spanning from July 2018 to December 2021. The comet detected at least twelve &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;relatively large outbursts, during which its brightness increased by 1.5 to 5 mag. as &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;measured through a 5 arcsec aperture. The variation of the cometary brightness profile &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;is clear to be found during the outbursts. The derived slope of the surface brightness &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;profiles are significantly varying with time from the shallower slope to a steeper one &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;at the beginning of each outburst and then slowly back to pre-outburst values. The &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;color indices seem to not be obviously changing as outbursts occurred. But for the &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;quadruple outbursts in late September of 2021, we can confidently spot the change in &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;the color of the comet, and point out that the color indices seem to be lower than the &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;mean values, especially in B-V. Dust production derived by using the parameter Af&lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;&amp;#961; &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;from R-band photometry measurements shows a large increasing trend accompa&lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;nied by outbursts. Using a simple model and the derived outflow velocity of 0.11 km &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;s&lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;&amp;#8722;&lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;1&lt;/span&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;from the expanding shell features, an estimated lower limit of 1.0&lt;/span&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;&amp;#215;&lt;/span&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;10&lt;/span&gt;&lt;sup&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;8&lt;/span&gt;&lt;/sup&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;kg and &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;2.7&lt;/span&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;&amp;#215;&lt;/span&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;10&lt;/span&gt;&lt;sup&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;9&lt;/span&gt;&lt;/sup&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;kg of dust was released during the quadruple outbursts using the specific &lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;dust size, 1&lt;/span&gt; &lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;&amp;#956;&lt;/span&gt;&lt;span dir=&quot;ltr&quot; role=&quot;presentation&quot;&gt;m.&lt;/span&gt;&lt;/div&gt;
&lt;div class=&quot;annotationLayer&quot;&gt;&amp;#160;&lt;/div&gt;