Affiliation
Association Francaise des Observateurs d'Etoiles Variables (AFOEV)
Sun, 03/22/2015 - 09:22
PNV J20145000+1903300: possible nova (8.5 mag) in Sagitta
Discoverer: Akihiko Tago, Okayama-ken, Japan
R.A. 20h14m52.98s Decl. +19°03'52.2" (J2000.0)
2015 March 21.758 UT, 8.5 mag (CCD, unfiltered)
"2015 03 21.758 UT
Discovered A. Tago, Okayama-ken, Japan, on two frames using a Digital camera + 105-mm f/3.2 lens. There is no information about the past frame. Position end figures 02s.84, 25".0 +/- 5" from two JPEG frames measured by Nakano."
"2015 03 21.758 UT
Sorry position from JPEG frames is 20h 14m 52s.98, +19o 03' 52".2, +/-5" correctly."
http://www.cbat.eps.harvard.edu/unconf/followups/J20145000+1903300.html
Clear skies,
Patrick
The following star of magnitude 15 is 6" from the possible nova's position measured by Syuichi Nakano:
USNO-B1.0 1090-0509425 (20 14 52.853 +19 03 57.76)
B1= 16.41, R1= 15.10, B2= 16.26, R2= 15.20, I= 14.91 mag
NOMAD1 1090-0546039 (20 14 52.843 +19 03 57.74)
B= 15.75, V= 14.98, R= 15.20 mag
GSC2.3 N2PN032700 (20 14 52.827 +19 03 57.53)
F= 15.08, j= 16.39, V= 15.48, N= 14.36 mag
2MASS 20145283+1903575 (20 14 52.835 +19 03 57.56)
J= 13.503, H= 12.946, K= 12.878 mag
WISE J201452.84+190357.5 (20 14 52.842 +19 03 57.51)
W1= 12.795, W2= 12.907 mag
Regards,
Patrick
Several followup reports have not confirmed this outburst (including data from BSM_NM).
Arne
This is an odd situation indeed. I know myself that Tago has long been a very careful, meticulous and serious observer, as his record of previous discoveries over the past 50 years indicates. He's not easily going to be tricked. That he obtained two separate frames that show the interloper and demonstrating it to be stationary among the stars makes this sighting difficult to explain. Certainly it could not be a satellite reflection and no comets or asteroids are near Tago's given position. So what does that leave?
J.Bortle
I'm not an expert on flare stars, but my understanding is that red dwarfs can undergo high-amplitude flares and then fade very rapidly. Might this be what was detected? Assuming the updated position to be correct, I'd be hesitant to write this off as a mistake, for the reasons that John Bortle mentioned.
Colin
PNV J20145000+1903300 is certainly not a nova but a (non-astrophysical?) transient of currently unknown nature – unless the reported position is completely wrong (it had to be corrected once). We have to wait for Akihiko Tago's (or Syuichi Nakano's) further comments. In the meantime maybe someone can take a wide-field image of this area (just in case).
Patrick
Here is a V-band 2.2x1.4 degree field of view taken this morning with BSM_NM, centered on the reported transient position. It is a crowded region, so I have not inspected it to see if there is something new within the field but not at the reported position.
Arne
For those not familiar with the BSM, the coordinates and size are Center (RA, hms): 20h 14m 50.788s (Dec, dms) +19° 04' 10.260" Size 2.22 x 1.49 deg.
Thanks to Astrometry.net! - Lew
We have had these kinds of "ghost transients" reported before. I had previously strongly recommended people do a visual confirmation check before submitting. It takes but a couple of minutes, and a bright object like this could easily be visually confirmed to be real or not, with binoculars or small telescope.
I have seen peculiar "transient" objects on my BSM system now and then. Could be cosmic ray hits, readout errors, foreign matter on filters, detectors, etc, etc.
Prudence should always be a priority!
Mike LMK
Nova serachers usually find a candidate after morinig has come at thier location.
Thus they need to wait another night to check it by themselves.
Recently, conformation is done by other observers at other longtitude where is night.
Thus, I reccomend that discovers don't need to wait aother night to confirme it and you don't hegitate to report your probable nova.
Early alert is important to eraly multi-color observations of novae.
And I prefer eraly false alert than late reliable report.
Sometimes I wish that they use photometric filters when they took partol images with little hope. I kow that they want to took more and more deeper images without filter and photometric filters are not cheap.
Seiichiro Kiyota
I also took confirmation images of Tago's PNV. But, I did not report as many others already reported thier results.
Considering the fact Sagitta hosts a lot of variables, it is close to Milky Way, it's rising earlier;every day for Northern observers and can be encompassed in 50 to 135 mm len + DSLR + star tracker ;- and the fact I need some target to get rid of rust
according to your opinion is this object worth monitoring anyway ?
Giancarlo Gotta
Hi Giancarlo,
We haven't heard from the discoverer if they have found any potential problem with their data. Considering that the closest star is about 16mag, this would be a 7+ mag outburst that disappeared the next day, which is larger than I've ever heard of for a flare star. Therefore, it either doesn't exist, or it is some exotic variable. Of the two, I'd bet strongly on the non-existence theory.
That said, like you mention, there are plenty of variables in the field, so if you decide to monitor that field, primarily to get photometry of the other stars, but also to cover the unlikely possibility of something exciting, you would not be wasting your time and might get lucky. It just depends on your other projects and whether there is a "free slot" for such monitoring. The Bright Star Monitors have other higher priority targets (such as the Sgr and Sco novae) and so I won't be leaving this field in their queues.
Arne
Can someone post here the original images showing this object, please?
Mike LMK
All this talk on wide field monitoring wants me to take my CCD off the main (33cm) scope and attach the 200mm to the ST-10XME&CFW-10 with this new adapter I got from Italian Astroimager Paolo Candy! Unfortunately my East is almost completly inaccessable with trees almost covering to 1 hr E. of zenith! All my variable star imaging occurs to objects at zenith and setting.
James
Hi James,
Many nova searches choose their monitoring fields in ways to optimize return. They observe the galactic plane, especially near the bulge, as historically that is where most novae occur. Since these regions are currently in the early morning sky, you will not be able to monitor them yourself until they reach that magic -01:00 hour angle in darkness for your location. This is also why often new novae show up in March/April - the plane is very low in the east, just rising before dawn, and there are novae that went into outburst while the fields were behind the Sun, but now becoming visible.
This can mean that some novae are being missed, because their fields are not being targeted. ASAS did a nice job of covering all of the southern sky every few nights while it was running (and its upgrade ASAS-SN should be doing the same, though they've been announcing mostly SNe and CVs so far). The proposed AAVSO 2GSS survey would also give real-time alerts on a daily basis, and the new Evryscope when fully functional will be another source of discovery information. Until they are working and producing real-time alerts, you can still outdo them with your own system, and with the 200mm aperture, you can go fainter than most of those surveys. So monitoring fields with a wide-field system isn't a bad choice, just a very software-intensive one. As has been mentioned before, you have a huge multiplexing advantage with a wide-field system, so you can report photometry for many variables in each image.
Arne