Affiliation
American Association of Variable Star Observers (AAVSO)
Fri, 04/26/2013 - 20:06
Welcome to the nova forum!
Have you ever wondered about novae -- why they behave the way they do, whether you should observe them, which ones you should observe, what professional astronomers do with the observations that you submit, or whether your observations have contributed to a scientific discovery?
This is exactly the type of thing that we will be discussing in this forum. So please join me with your questions, answers, and ideas about novae!
I hope to hear from you.
- Jeno Sokoloski
Hi Jeno,
This forum is a wonderful idea, novae are so fascinating events.
Amateurs of ARAS (Astronomical Ring for Access to Spectroscopy) gather their novae spectra on a web page : http://www.astrosurf.com/aras/novae/Novae_Aras.html, with the AAVSO light curves
The brighter novae are followed as long as possible. For instance, the nova outburst of the symbiotic V407 Cyg, up to mag 14
http://www.astrosurf.com/aras/V407Cyg/v407cyg.htm
or more recently Nova Mon 2012, with 61 spectra since august 2012 to april 2013
http://www.astrosurf.com/aras/novae/Nova2012Mon.html
The fit files are organized in a table with public access http://www.astrosurf.com/aras/novae/TableauSpectres.htm
waiting an international data base for amateur spectra ....
Some attempts of line analysis : http://www.astronomie-amateur.fr/feuilles/Spectroscopie/Novae/Nova2012Mon_Analyse.html
which shows the quality of the results obtained by various observers.
Best regards
Francois Teyssier
Coordinator for novae and eruptive stars in ARAS
francois.teyssier@dbmail.com
Hi Francois. It is wonderful that you and your organization are putting so much effort into obtaining spectra of novae! In my work, I make particular use of ejection velocities that are estimated from line widths at early times. Our radio observations give an estimate of the size of the ejecta on the sky, and when we combine that with an estimate of the true size from the ejection velocity (multiplied by the time since the start of the eruption), we can get an immediate estimate of the distance to the nova.
We are also finding that the ejection histories can be quite complex, and so monitoring the evolution of line width is also very interesting.
- Jeno
It's a great initiative for the AAVSO to refocus on novae. This kind of objects led amateur observers to be in cooperation with professionals decades ago.
I fear that there are not as much opportunities for amateur to discover novae as in the past because moder sky surveys are very efficient detecting transient phenomena. Even though, modern amateur hardware can let to achieve discoveries.
I've been involved in novae observation when V723 Cas (nova Cas 1995) exploded, thanks to it's very slow development. This phenomena made me to study this nova and novae in a wide sense.
I think, astronomers like Jeno can encourage amateur community a lot to maintain sustaining observations sharing their progress in their research and involving non professionals in observign campaigns.
Now I observe ancient novae more often that recently exploded, as I am able to reach fainter magnitudes with 8" aperture and CCD. I would like to ask Jeno if post-explosion (some years or even decades after explosion) photometry is valuable.
Regards
Miguel
Hi Miguel! Thanks for your post. You mentioned two things: nova searches and late-time photometry. I think there is an important role for amateurs in both of those areas.
In terms of searching for novae, Brad Schaefer (Louisiana State University) believes that half of all novae are currently missed, even if they are extremely bright. Many automated surveys do not have the ideal cadenence or sky coverage for catching novae, and so amateurs could help fill those gaps.
Regarding late-time photometry, it is very interesting to determine when rapid (minute-time-scale) flickering resumes because this flickering typically indicates that the accretion disk has re-formed. Also, photometry for years, decades, and even centuries after an eruption could provide information about how the nova eruption influences the accretion rate and the long-term evolution of the binary. So, this long-term monitoring is very useful indeed!
- Jeno
Jeno, I agree with Brad Schaefer concerning almost half the novae that occur are missed. Speaking from personal experience as an active visual nova hunter both in the UK as well as here in the States with the AAVSO.
In mid January 1981 while still residing in the UK I had the good fortune to discover Nova SCT 1981 at visual magnitue 8, while the following morning was overcast a clear sky on the next morning revealed that the object had faded to 9th magnitude and soon after had faided completely.
Fortuntely an image taken with a telescope at the RGO (Royal Greenwhich Observatory) confirmed it's existance and whether it was a nova or a nova like object, well that remains to be seen. This region of the sky was returning from being behind the sun, so it could have been much brighter than 8th magnitude, or then again it may perhaps have had a rapid rise peaked at or near 8th mag,followed by a rapid fade ?
Either way if the morning of the discovery had been overcast, or that nice warm bed had persuaded me to stay putt then this object would have slipped away.
- Dave Branchett
I want to add that use of photometric filters, and photomery in several bands can improve scientifc value of observations.
This is a great idea that will expand pro-am collaborations. So many amateurs and professionals are really unaware of what each is doing, and what resources are at their disposal. And it can be a little daunting for the amateur that begins to wade into this territory of collaboration.
In addition to notification, and monitoring, I'd like to see something applied here similar to what Alan Alda is doing to help scientists communicate better with the amateur (I learned about this from a CBS Sunday Morning segment). Check it out: http://www.centerforcommunicatingscience.org/
Michael
Hi Michael. Thanks for the link -- I'll have a look. :)
- Jeno
Of the 20 Milky Way/Magellanic Cloud novae reported in 2012, 14 were amateur discoveries and 6 professional. 19 of the 20 novae were southern objects with only Nova Monocerotis 2012 marginally a northern object (declination +5 degrees). John Seach of Chatsworth Island, NSW, Australia, was the most prolific nova discoverer (amateur or professional) with five.
Of the professional discoveries, MOA 2012 BLG-320, OGLE-2012-NOVA-002 and WISE J18183400-2849196 were spectroscopically confirmed as novae while Swift J1745108-262411 was classified as an x-ray nova or black-hole binary candidate. Only one professional discovery was reported via CBAT’s Transient Objects Confirmation Page aka TOCP (OGLE-2012-NOVA-003 = PNV J05202109-7305433), the others being reported through The Astronomers’ Telegram.
One professional discovery, WISE J18183400-2849196, was apparently in outburst in 2010 but went unnoticed at the time and was discovered through archival images. Nova Sagittarii 2012 No. 2 was another strange one whose outburst began in 2010 and was still easily detectable in early 2012.
Of the three Magellanic Cloud novae, two were in the LMC and one in the SMC. Only one was an amateur discovery, Nova LMC 2012. The professional discoveries were first detected as faint objects in decline and traced backwards to outburst through archival images.
A further eight reports of “possible novae” (PNV) were made to TOCP in 2012, one professional and seven amateur. Four were “no object at that position”, one a dwarf nova, one a K3 star, one a “red star” and one was the previously-discovered Nova Scorpii 2012.
The number of novae discovered in 2012 was a record for any year.
So there's obviously a strong continuing role for amateurs in nova discovery! The ability to take DSLR widefields at moderate depths only is all that is needed to participate, and detection can be as simple as visually 'blinking' images (or you can make it as complicated as you like with software!). If you know your fields well enough I'm sure there is still a role for visual observers, picking up anomolous stars in your usual observing fields. The important thing is that the earlier the detection, the more information that can be gained by suitably-alerted professionals. And amateurs still have a role beyond discovery, in the production of light curves & spectra (data gathering).
Cheers -
Rob Kaufman (KBJ)
Bright, Victoria, Australia
Hi Rob. Thanks for this comprehensive and inspiring description of nova discoveries in 2012. You have clearly demonstrated that amateurs not only have a role in nova discovery, but that they are actually still the primary source of nova discoveries!
The thing to remember, though, is that searching for novae is a bit like playing the lottery (in the words of my colleague Joe Patterson) -- the payoff is potentially high, but most searchers are very likely to come away empty handed.
- Jeno
How very true Jeno! I've been searching for a few years now without success but the sense of anticipation after I have imaged a field is exactly the same as when I first started! There have been a few close calls, particularly with one of the Sagittarius novae last year. Providing the earliest confirmation of possible novae can be rewarding too!
The other thing that helps hold the interest for me is tracking down apparent 'hits' in the images - they might be minor planets, Mira-type stars in fields with gaps in imaging, eclipsing binaries etc, or even just the run-of-the-mill cosmic ray hits! You learn so much about other stars in your fields over time, and through blinking frames you get to graphically witness the ever-changing night sky.
For people who have limited equipment, who don't have the time or inclination to engage with the level of sophistication demanded of CCD (& DSLR) photometry, who don't necessarily have the discipline for visual observing (I'm in awe of people like Rod Stubbings, Mike Linnolt etc!), nova search can offer a simple, enjoyable and useful way of contributing.
Rob
Hi Rob. Thanks so much for providing this perspective on doing nova searches. If any of you do get lucky and find a new nova, my collaborators and I will do our best to get radio and X-ray observations of it!
- Jeno
Jeno,
You mention radio observations of novae. Is there a place for people interested in radio astronomy in this forum?
My education & professional experience is in electrical engineering with speciality in radio frequency technologies. I belong to the Society of Amateur Radio Astronomers (SARA) and recently wrote a paper for their journal about using the Internet as a radio astronomy observatory for amateur research. In particular, I talk about using the large databases of organizations such as the NRAO. These are generally open to the public.
So I was just wondering if this might be of some use to this forum. I would certainly be interested in participating.
Dave Hinzel
Hi Dave. I'm very glad you asked about radio observations of novae, because that is actually my field of interest!
In a later post, I plan to describe my research in more detail. In a nut shell, several years ago, some colleagues and I formed what we call The ENova Project, and our goal was to use the new capabilities of the National Radio Astronomy Observatory's Expanded Very Large Array (now renamed the Jansky VLA) to address several major open questions about novae. Since radio observations are a more direct probe of the amount of mass that is ejected than optical observations, radio observations have the potential to answer one of the biggest questions -- how much mass is expelled?
Overall, I think the best way to learn about novae is the combine observations at multiple wavelengths.
- Jeno
Jeno,
This is good to hear!
I agree that multispectral is the way to go. In fact I just joined iTelescope 2 days ago and (once I get up to speed on things, which may take a while!) I plan to do some multispectral work (optical & RF...and others as necessary). So this nova forum is perfect for that! Since I'm not a professional astronomer the learning opportunities will be great.
By the way, I'm also interested in the Data Analysis/LAVA forum that David Benn is leading. I've done some work in data mining/data analysis with the Lowell Observatory Lowell Amateur Research Initiative (LARI). The project I'm on is MGED which studies light curves to look for exoplanets. Not sure how that is related to this forum, but I thought I'd mention it!
Dave
Hi Jeno, thanks for your answers. As I understand for your comments, the two issues save a wide field for amateurs to contribute and collaborate with professional astronomers.
Hi Dave,
The Data Analysis forum is also new but isn't formally linked to the nova project, at least no more than it is to any other variable star research that the AAVSO community pursues. That said, there's probably room for a lot of people doing analysis just like there is for doing observation!
We've had a small project going for a few years now, hoping to get archival photometry of novae online. This includes novae going far into the past (e.g. Nova Persei 1901, added to the database by Bob Stine). I definitely encourage people to look over older data sets -- it's good to have an eye on what can be learned from data, but they're also useful just to educate yourself about what the observational histories are.
It's great to see the discussion here so far!
Matt
Matt,
I just wanted Jeno to know that I was also interested in data analysis as well as observing (once I get better using the iTelescope system). I plan to participate in both forums (data/nova). I'll start with the data forum since I have a bit of experience with the LARI MGED program.
Dave
Hi Jeno,
Do you have a downloadable copy of your conference presentation?
Dave
Hello Dave,
A PDF of Jeno's presentation at the Spring 2013 meeting is available at this URL.
Clear skies,
Matthew
Hi Matt,
Thanks for the URL. Been out of town last few days and just saw this.
Dave