By Victor Davis

The March, 2022 meeting of the AAAP will take place (virtually) on Tuesday, March 8^th at 7:30 PM. (See How to Join the March Meeting below for details). This meeting is open to AAAP members and the general public. Participants will be able to log in to the meeting as early as 7:00 pm to chat informally with others who log in early. We will not be using the “waiting room;” participants will enter the meeting as soon as they log in. However, you will enter the meeting space with your microphone muted. This will help to remedy some of the background noise we experienced during some previous meetings. Please be aware you must unmute yourself to be heard by other participants.

For the Q&A session, you may ask your question using Zoom’s chat feature or you may unmute yourself and ask your question directly to the speaker. To address background noise issues, we are going to follow the rules in the table below regarding audio. If you are not speaking, please remember to mute yourself. You are encouraged, but not required, to turn your video on.

Meeting Event	Participant Can Speak?	Participant Can Self-Unmute?
Pre-meeting informal chatting	Start All on Mute	Yes
Director Rex’s General Remarks	Yes	Yes
Program Chair Victor’s  Speaker Introduction	Yes	Yes
Speaker Presentation	No	No
Q&A Session	Start All on Mute	Yes
5-minute bio break	Yes	Yes
Journal Club presentation by Rich Sherman	Start All on Mute	No
Business Meeting	Start All on Mute	Yes
Director’s closing remarks/Informal chatting	No	No

Featured Speaker:  Dr. Roseanne Di Stefano, a Senior Astrophysicist at the Center for Astrophysics, Harvard and Smithsonian. 

(rdistefano@cfa.harvard.edu)

Planets in External Galaxies

Most of the exoplanets (4,651+) discovered to date were detected by looking for tiny diminutions in a star’s visible light when a non-luminous object transits in front of it. Almost all exoplanets and exoplanet candidates are within 3,000 light years of Earth, well within the Milky Way galaxy. Dr. Di Stefano and her colleagues may have detected signs of an exoplanet transiting a star outside of the Milky Way, in M51, the Whirlpool Galaxy, about 28 million light years away.

They did this by examining data from the Chandra X-ray Observatory to look for dips in the brightness of X-rays received from bright X-ray binaries in galaxies M51, M101, and M104. Of the 238 binary systems observed, one exoplanet candidate turned up, now known as M51-ULS-1. This binary system contains a neutron star or black hole orbiting a 20-solar-mass companion star. Because the region glowing in X-rays is small, a transiting planet could block much or all of its X-ray emission, making it easier to spot. In the case of M51-ULS-1, the X-ray emission decreased to zero in the space of three hours. The researchers estimate the exoplanet candidate to be about the size of Saturn at about twice Saturn’s distance from the Sun. So, a confirming observation is about 70 years away.

Dr. Di Stefano will describe her research and its implications for planetary studies, including possible extensions of this work to X-ray binaries in additional galaxies and in the Milky Way.

Dr. Roseanne Di Stefano is a graduate of Queens College, CUNY, Columbia University, and SUNY Stony Brook. She’s a Senior Astrophysicist at the Harvard-Smithsonian Center for Astrophysics. Her thesis work was on Hamiltonian dynamics and supersymmetry, but she has been researching questions in astronomy since the 1990s, first at MIT, then at Harvard and at the Smithsonian Astrophysical Observatory. Her current professional interests are on binaries and triple star systems, particularly topics related to the progenitors of Type 1a supernovae, gravitational mergers, and binary self-lensing. She has conducted studies of both newly collected and archived X-ray data and is engaged in time series analysis for both X-ray and optical events, including microlensing. She is a member of the Vera Rubin Observatory’s team on transients. She’s active in science education and outreach, and in community service in the US and abroad.

AAAP webcast:  This month’s AAAP meeting, beginning with Rex’s opening remarks and ending at the beginning of the business meeting, will be webcast live on YouTube and recorded for subsequent public access on AAAP’s YouTube channel. Be aware that your interactions during this segment, including questions to our guest speaker, may be recorded for posterity. 

YouTube Link: Amateur Astronomers Association of Princeton, January 11, 2022 Meeting, 7:30 PM EST

This session will be recorded and saved on YouTube. Send me an email at program@princetonastronomy.org if you have any concerns. 

Using Zoom: While we are social distancing, the AAAP Board has chosen to use Zoom for our meetings, based our belief that many members have already have used Zoom and its ease of learning. One of its great features is you can choose whether you want to install the software on your computer or use it within your browser.

How to Join the March Meeting: For the meeting, we are going to follow a simple two-step process:

1. Please make sure you have Zoom installed on your computer. You do not need a Zoom account or need to create one to join the meeting. Nor are you required to use a webcam.
2. Please visit our website for the Zoom link.

This session will be recorded and saved on YouTube. Send me an email at program@princetonastronomy.org if you have any concerns.

NOTE: The Zoom site has many training videos. If you’re unsure how Zoom works you might want to view the videos on how to join a meeting or how to check your computer’s audio and video before the meeting.

Link to join March’s Zoom Meeting
Amateur Astronomers Association of Princeton is inviting you join our February monthly meeting.

Topic: Monthly AAAP meeting with Rosanne Di Stefano and a possible detection of an exoplanet in M51 which is 28 million light-years away

Time: March 8, 2022 07:00 PM Eastern Time (US and Canada)

Join Zoom Meeting

https://us06web.zoom.us/j/81902801493?pwd=NTA3SHByYVYvaGNGU1VVSklaeGRnQT09

Meeting ID: 819 0280 1493

Passcode: 844404

“Unjournal Club”

Following the post-presentation bio-break, Rich Sherman will present a travelogue of his trip to Lowell Observatory outside Flagstaff, Arizona.

We hope to make these short presentations a regular feature of our monthly meetings. We’d like to know what members are doing or what members are thinking about in the broad range of topics encompassed by astronomy. A brief ten-minute (or so) presentation is a good way to introduce yourself and the topics you care about to other club members. If you are interested in presenting a topic of interest, please contact either director@princetonastronomy.org or program@princetonastronomy.org.

A look ahead at future guest speakers:

April 12, 2022	Paul Daniels, FRAS, an active participant in the Royal Astronomical Society’s Megaconstellation Working Group, will discuss the serious threats to professional and amateur astronomy posed by launching thousands (potentially 100K+) of reflective objects into low Earth orbit.
May 10, 2022	Kenneth Chang, science writer for the New York Times who describes his beat as “chemistry, geology, solid state physics, nanotechnology, Pluto, plague and other scientific miscellany” also writes frequently on space missions and astronomy. He has not yet decided on a title or topic for his presentation.
June 14, 2022	Bill Murray, AAAP Outreach Chair and astronomer at the New Jersey State Museum will once again (following a Covid hiatus) give club members a private sky tour at the museum’s planetarium. He’ll show off the refurbished planetarium’s state-of-the-art Digital Sky 2 8K projection system. This is an opportunity to put aside Zooming and commiserate with astro-buddies in the real world.

Thanks to Bill Thomas, Ira Polans, and Dave Skitt for their valuable advice and assistance.

As always, your comments and suggestions are gratefully accepted.