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<div class="">Dear all,<br>
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<div class="">It is our pleasure to announce that this week we will have Biwei Jiang visiting us here at Stockholm University, all the way from Beijing Normal University, and giving this Friday's SU astronomy departmental seminar on<b class=""> April 28th at
10:30am in room FC61</b> (AlbaNova building, 6th floor) <b class="">and on zoom (<a href="https://stockholmuniversity.zoom.us/s/61002076352" target="_blank" rel="noopener noreferrer" class="" id="LPlnk88844" style="font-weight:normal">https://stockholmuniversity.zoom.us/s/61002076352</a>).</b>
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<div class=""><b class="">Speaker: Biwei Jiang (<span>Beijing Normal University, BNU</span>)</b><br class="">
<b class="">Title: </b><b class=""><span>The sample and mass loss rate of red supergiants in M31 and M33</span><br class="">
</b><a href="https://www.albanova.se/event/astronomy-departmental-seminar-tadafumi-matsuno-groningen/" target="_blank" rel="noopener noreferrer" class="x_OWAAutoLink" id="LPlnk433740"></a><a href="https://www.albanova.se/event/7310/" class="OWAAutoLink">https://www.albanova.se/event/7310/</a></div>
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Abstract:</div>
<div class=""><span class="x_read-more-text"><span>Red supergiants (RSGs) are important contributors to interstellar medium through massive winds. Due to serious interstellar extinction, the complete sample of RSGs is extremely difficult to obtain in our Galaxy.
As two of the largest spiral galaxies in the Local Group, M31 and M33 can serve as references to analyze the global contribution of RSGs to the galactic medium. By using evident branching of red dwarfs and red (super)giants in the near-infrared color-color
(J-H/H-K) diagram, the foreground dwarf stars are excluded efficiently with the UKIRT observational data, The most complete and pure sample of RSGs in M31 and M33, specifically, 5498 and 3055 RSGs respectively, are obtained from the color-magnitude ( J-K/K)
diagram of the member stars. The dust radiative transfer model, the DUSTY code, is run to calculate the mass loss rate of RSGs. The average mass loss rate of RSGs is found to be around 2.0 ¡Ñ 10<sup>-5</sup> M<sub>¡ó</sub> yr<sup>-1</sup> with a gas-to-dust
ratio of 100, which yields a total contribution to the interstellar dust of about 1.1 ¡Ñ 10<sup>-3</sup> M<sub>¡ó</sub> yr<sup>-1</sup> in M31 and 6.0 ¡Ñ 10<sup>-4</sup> M<sub>¡ó</sub> yr<sup>-1</sup> in M33, a non-negligible source in comparison with evolved
low-mass stars.</span></span></div>
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We look forward to seeing many of you there. Thanks!</div>
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Eliot and Kris</div>
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<div>Note, there will also be an additional seminar this week <b class="">on Wednesday April 26th at 14:30 in room FC61</b> by our own Alexandra Lereste (SU).
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Upcoming Events:<br class="">
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<div class="">2023-04-26 Alexandra Lereste (SU) <¡X Note this is on a Wednesday (time 14:30 - followed by Fika)<br>
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<div class=""><span>2023-05-05 <span>Natalia Lahen</span> (MPA Garching)</span></div>
<div class=""><span>2023-05-12 <span>Jin Koda</span> (Stony Brooke University)</span></div>
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<div class="">The calendar for later planned seminars is available <a href="https://ebox.su.se/owa/calendar/75d76b284ca84db1a85c4e021d1133e8@astro.su.se/22bc11d486d04afaa009a9730dd065d65524176602456481514/calendar.html" target="_blank" rel="noopener noreferrer" class="">here</a>.</div>
<div class="">(Please note that calendar can be subject to updates)</div>
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<div class="">Join Zoom Meeting:<br class="">
<a href="https://stockholmuniversity.zoom.us/s/61002076352" target="_blank" rel="noopener noreferrer" class="">https://stockholmuniversity.zoom.us/s/61002076352</a></div>
<div class="">Meeting ID: 610 0207 6352</div>
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