Serving science and society since 1937. The National Capital Astronomers (NCA) is a non-profit, membership supported, volunteer run, public service corporation dedicated to advancing space technology, astronomy, and related sciences through information, participation, and inspiration, via research, lectures and presentations, publications, expeditions, tours, public interpretation, and education. NCA is the astronomy affiliate of the Washington Academy of Sciences. We are also members of the Astronomical League, in fact NCA members helped form the Astronomical League a long time ago.
NCA has for many years published a monthly newsletter called Star Dust that is available for members. Besides announcement of coming NCA meetings and a calendar of monthly events Star Dust contains reviews of past meeting and articles on current astronomical events.
NCA is a very unusual astronomy organization. All are welcome to join. Everyone who looks up to the sky with wonder is an astronomer and welcomed by NCA. You do not have to own a telescope, but if you do own one that is fine, too. You do not have to be deeply knowledgeable in astronomy, but if you are knowledgeable in astronomy that is fine, too. You do not have to have a degree, but if you do that is fine, too. WE ARE THE MOST DIVERSE local ASTRONOMY CLUB anywhere. Come to our meetings and you will find this out. WE REALLY MEAN THIS!
NCA has regular monthly meetings September through June on the second Saturday of the month. For 2022-2023, the meetings will be held online via Zoom.
The meetings for this year will be VIRTUAL and not in-person.
With permission of the speakers, most meetings will be recorded. Once available the audio and video will be linked.
National Capital Astronomers will be holding its 2022-2023 meetings online via Zoom. This year, the Zoom meetings have been set up so that there is no registration required. This is the direct Zoom link, it is the same for everybody for every meeting this year (2022-23). If we have problems with Zoom bombing at a meeting, then the link will be canceled and a new one created that will require registration for subsequent meetings.
As usual, the Zoom room "doors" open at 7pm ET with the actual meeting starting on time at 7:30pm! While you do not need to sign in right at 7pm, please do not wait until 7:35pm!! And since we are not registering folks, it will be important that you have a recognizable name showing so that I can let you in from the virtual waiting room.
Finally, as last year, with the permission of the guestspeakers, we will be recording the meetings.
Join Zoom Meeting: NCA Monthly Zoom
These guidelines will be updated as needed.
Alex Dittmann, UMD
7:30 pm ONLINE.
Abstract: The accretion disks which power active galactic nuclei (AGN) may harbor large populations of stellar-mass objects. Stars may form in-situ due to the gravitational instability of outer regions of the disk, and stars and black holes may be captured into the disk from a nuclear star cluster through a number of mechanisms. These populations of embedded objects may be responsible for a large fraction of the gravitational wave events observed by LIGO, the chemical evolution of AGN disks over cosmic time, the rapid growth of supermassive black holes in the early universe, and numerous anomalous transients observed in time-domain surveys. Stellar populations in the Milky Way's center may also have been sculpted during our Galaxy's most recent active phase. I will review earlier work on stars irradiated by accreting supermassive black holes and how accretion disks may capture stars on intersecting orbits. Subsequently, I will present recent developments in understanding the evolution of stars within AGN disks: how accretion can rapidly grow stars to hundreds of solar masses, sustain "immortal" stars which cease to chemically evolve, and how disk properties affect these modes of evolution.
Bio: Alex Dittmann is a PhD candidate in Astronomy at the University of Maryland. He received undergraduate degrees in Physics and Astronomy from the University of Illinois in 2018, where he won the Stanley Wyatt Memorial Award. In 2022 he was a co-recipient of the Bruno Rossi Prize as part of the NICER team.
A few of his research interests include compact objects and astrophysical constraints on the equation of state of dense matter; accretion disks, particularly their interaction with binaries; and developing new high-order algorithms for solving differential equations.
The telescope making, maintenance, and modification workshop with Guy Brandenburg is held in the basement (wood shop) of the Chevy Chase Community Center which is located at the intersection of McKinley Street and Connecticut Avenue, NW, a few blocks inside the DC boundary, on the northeast corner of the intersection. The workshop is open on Tuesdays & Fridays, from 5:00 to 7:30 PM. For information visit Guy's Website. To contact Guy, call 202-635-1860 or Email Guy.
Exploring the Sky is an informal program that for over seventy years has offered monthly opportunities for anyone in the Washington area to see the stars and planets, through telescopes, from a location within the District of Columbia. During all those years, it has been co-sponsored by NCA and the National Park Service. Face masks are optional.
Questions? Call NCA at 202-635-1860 and leave a message.
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