SNEWS (SuperNova Early Warning System) is exactly what its name implies: it is a system that can give us an early warning about a certain type of supernova happening in our own galaxy (and neighborhood) when a massive star ends its life and collapses into a neutron star or even a black hole. When it happens, neutrino detectors will detect the signature of the collapse even before we can see the event in optical spectrum because the collapse will take some time to propagate to the layers of the star that are transparent to optical wavelengths.
SNEWS now enlists volunteers to perform a first “fire-drill” to practice performing observations of such an event by amateurs.
Here is the plan:
- if you are interested, register with your e-mail address at https://tinyurl.com/snews-firedrill .
You will receive a confirmation email and soon afterwards, the participants will be asked to provide further details about their equipment and observation site
- This is supposed to start a dialogue. Very likely there will be at least one Zoom meeting to discuss the details of the fire drill and to discuss observation techniques
- If all goes according to plan, the actual 1st fire-drill will already happen in October 2022. A simulated SNEWS alarm will be sent out to participants of the fire-drill who will then be challenged to respond as fast as they can.
To learn more about SNEWS, the following links might be helpful:
AAVSO webinar with Dr. Dan Milisavljevic https://youtu.be/3TeQgOoCy-E
SNEWS Webpage: https://snews2.org/
See the next message for some frequently asked questions and answers on this topic
Q: Why all the fuss? We have measured the light curves of so many SNe before, why bother?
A: Observing a core-collapse supernova in our own galaxy is a different thing scientifically. We will, for the first time, have a chance to observe both the neutrino emission and the first optical signal (shock breakout), and the time delay between these will tell us a lot about core collapse supernovae physics in general. If we are really lucky, we will be able to identify the progenitor star in archival data so we might be able to tell what happened to that star even before it went kaboom! The light curve of the SN days and months after the SN will actually not be so important, the big prize is to catch the very first optical signal! And amateurs can be part of this!
Q: But it should be super bright, as SNe can outshine their entire host galaxies, so it will be trivial to observe, right?
A: No, very likely it will not be super bright as seen from Earth. Most likely, the next galactic core collapse SN will happen somewhere in the galactic disk, and there will be a 50:50 chance that it will even happen on the far side of the galactic disk. So most likely we will be seeing the event through the thick dust and gas material that is in the disk. The event will then appear quite reddened but very likely still in a magnitude range accessible for amateurs with telescopes or perhaps even telephoto lenses, but likely not as a “naked eye” event.
Q: Will the neutrino signal trigger tell us where the SN is happening?
A: Unfortunately, the sky localization of the neutrino signal will not be terribly good even after combining the data from multiple neutrino detectors across the planet. Likely, there will still be many 10s of square degrees of sky area where the SN could become visible.
Q: How long can the time delay between the initial alert and the optical SN be?
A: The delay can be as long as several hours or even days in extreme cases, it all depends on the star that collapses. It could also be much, much shorter. Reacting to a SNEWS alarm will need to be be both fast and persistent.
Q: How often will these events happen?
A: It is estimated that core collapse SNe in our galaxy happen just a few times per century, say every 30 years or so on average, roughly. Because few obsevations of such events are known in recorded astronomy history (all before the invention of the telescope), mankind obviously missed quite a few of them in the past, e.g. the one that created the famous and rather young Cas A supernova remnant (which also proves that these events are rarely super bright). But we will not miss the next event because now we have neutrino detectors!
Rule of thumb: you will have a reasonable chance to witness the next galactic core collapse SN in your lifetime, but if you miss it, don’t count on getting a second chance!
Q: How best to prepare for observing this event
A: Good question! The first step would be to participate in the 1st SNEWS fire-drill. We think it’s best to learn about preparing for this rare event by pretending it’s actually happening. So what will you do in that night? Think about it! Can you use wide-field optics (but those will suffer from blending the galactic plane). But where to best point your narrow-field optics?
Q: Can we predict which star goes SN next in our galaxy?
A: We know that certain types of stars. eg. red super-giants, are good candidates because we expect them to go SN as the next stage in their stellar evolution.
Q: So should we keep an eye on those candidate SN progenitor stars?
A: Absolutely yes! The AAVSO already has a program to observe these stars. If we are lucky, we are already observing the next galactic SN before it will happen, so to speak. And those are interesting variable stars anyway. But because our catalog of those candidate star is far from exhaustive for our galaxy, we cannot be sure that we will be so lucky to observe the next one to go SN. Still it will make sense to include the candidates that we know of in our observations when a SNEWS alarm happens. Let’s discuss this in the fire-drill preparation!
Q: Will there be additional fire-drill events after October 2022?
A: If there is enough interest, which we certainly hope, this could very well become a regular exercise. While the first fire-drill is mainly meant to bring together an initial team to try out the concept, we (SNEWS and the AAVVSO) can imagine to develop this into a series of drills that will be increasingly realistic, and hopefully also fun to do.
If you are interested in participating in the first (ever :-) ) SNEWS fire drill, you can still register given the link provided above! I think this will be a fun experience and your feedback can help us plan for more elaborate fire drills in the future!