[AZ-Observing] Re: AAVSO Alert Notice 437: Campaign to monitor T Pyx throughout 2011 eruption

  • From: "Wayne (aka Mr. Galaxy)" <mrgalaxy@xxxxxxxx>
  • To: aavso@xxxxxxxxx
  • Date: Sun, 17 Apr 2011 06:13:10 GMT

15480 Empire Rd.
Benson, AZ 85602
hm ph: 520-586-2244

Here's a fun (and rare) object to follow, the recurrent nova T Pyxidis! 

I just came in from observing it and estimate it to be about 7.5 magn visually 
through my 13-in f/5 reflector at about 100x. I could just barely detect it in 
my 50mm finder telescope, but it should become easier as it brightens and the 
moon starts to wane. I made two observations tonight (April 16/17): 10:30pm and 
10:45pm local AZ time with a nearly full moon in the sky and could see no 
change in brightness during that time. Using an e-scale chart provided by the 
AAVSO's website (see info below) I was able to see stars down to 12.5 magn and 
verified I had the correct field. I compared the nova to the 7.8 magn star near 
to the south as shown on the chart. The comp star seemed to be a little oranger 
than the nova and barely, but definitely fainter. Since I don't have setting 
circles (digital or otherwise) I had to starhop to the location. 

This would make an excellent field to image for submittal to the AAVSO and also 
for timelapse purposes to compare before and after. The last time this star 
erupted was some forty years ago. It's a bit far south, but it's fine for those 
in Arizona. Wish you luck! 

Clear skies, 
Wayne (aka Mr. Galaxy)


---------- Original Message ----------
From: aavso@xxxxxxxxx
To: mrgalaxy@xxxxxxxx
Subject: AAVSO Alert Notice 437: Campaign to monitor T Pyx throughout 2011 
eruption
Date: Fri, 15 Apr 2011 20:39:41 -0400

AAVSO Alert Notice 437

Campaign to monitor T Pyx throughout 2011 eruption
April 15, 2011

Further to AAVSO Alert Notice 436 
(http://www.aavso.org/aavso-alert-notice-436), a fast photometry 
observing campaign has been initiated by Dr. Bradley Schaefer 
(Louisiana State University) to monitor the recurrent nova T Pyxidis 
throughout its current eruption.

Brief summary of eruption: The recurrent nova T Pyx was discovered in 
outburst by M. Linnolt (Hawaii, United States) at visual magnitude 
13.0 on 2011 April 14.2931 (JD 2455665.7931), and confirmed by 
A. Plummer (Linden, NSW, Australia) at visual magnitude 12.2 on April 
14.3847 (JD 2455665.8847) and S. Kerr (Glenlee, QLD, Australia) at 
visual magnitude 11.3 on April 14.4410 (JD 2455665.9410).  This is 
the first outburst of T Pyx since December 7, 1966, nearly 45 years 
ago. As of April 15.6271 (JD 2455667.12708), it had brightened to 
visual magnitude 8.3 (A. Pearce, Nedlands, WA, Australia). If it 
behaves as in past eruptions, it can be expected to brighten to 
magnitude 6. All observations -- visual, CCD, and PEP observations, 
and CCD time series -- are encouraged.

Campaign: Full details of the campaign may be found on the T Pyx 
campaign information page (http://www.aavso.org/campaign-monitor-
recurrent-nova-t-pyx-throughout-2011-eruption). The following is 
a description of the campaign summarized from that page:

"The goal is be to get nearly-fulltime coverage of T Pyx with time 
resolution of minutes throughout the entire eruption up until T Pyx 
is lost behind the Sun around the start of August. This will require 
many observers, widely spaced around the world, each taking long runs 
of CCD images.  The eruption takes roughly 9 months to go back to 
quiescence, but we will only go from now until the end of July (3.5 
months) when T Pyx is lost behind the Sun.

"...V filter is preferred for CCD observations, with second choice 
being B filter, third choice R, and last choice unfiltered.  (T Pyx 
should be magnitude 6-10 over this whole time interval, so a filter 
will help against saturation.)  To make for a uniform magnitude scale 
by everyone, please use the following comparison stars:

COMPARISON: AAVSO="93"  HD77862    09:04:09.4 -32:11:16 B=9.85,V=9.31
COMP2:      AAVSO="69"  HD77645    09:02:51.8 -32:26:24 B=6.90,V=6.93
COMP3:      AAVSO="115" CD-31o6884 09:04:43.8 -32:24:47 B=12.12,V=11.52
Variable star (do not use):  
            AAVSO="84"   HD77938    09:04:29.5 -32:26:54 B=9.49, V=8.44

Please use the COMPARISON star (AAVSO="93") for all the differential 
photometry as it will have nearly the same colors as T Pyx.  Use the 
other backup comparison stars only if you have troubles with field size, 
saturation, or SNR problems. With the bright stars and differential 
photometry, T Pyx can be followed down low on the horizon.

"T Pyx is only one of ten known recurrent novae in our own Milky Way 
galaxy.  It has erupted in 1890, 1902, 1920, 1944, and 1967...we...are 
not missing any eruptions in this time interval...Judging from the 1967 
eruption light curve, the current eruption light curve will stall out 
of its rise at around V=8 around 15 April,  slowly rise to a peak near 
V=6.4 around 20 May, slowly fade to V=10 by middle August, then have a 
sudden drop by two magnitudes over the next 20 days (with drop being 
invisible due to the Sun)...

"Recurrent novae...are one of the best candidate systems for being the 
progenitor of Type Ia supernova.  This progenitor problem is a long 
standing sore mystery...Indeed, in last year's Decadal Survey, the 
National Academy of Sciences identified the progenitor problem one of 
the four most important problems in all astronomy...T Pyx...[is] the 
lynchpin of many arguments and discussions for the progenitor problem.  
The work on this eruption will largely be aimed at testing whether 
T Pyx will become a Type Ia supernova.

"...Only one nova has large amounts of fast photometry...the recurrent 
nova U Sco, which erupted in 2010.  For this, I organized a large 
worldwide collaboration of (mostly amateur) observers, and we measured 
37,000 magnitudes..With this awesome data set, we discovered two 
completely new phenomena...who knows what more will be discovered for 
the second very-well-observed nova.

"I envision a repeat of the wildly successful U Sco worldwide 
collaboration of astronomers, so that we can get very detailed light 
curves of T Pyx and all its expected-complicated variations throughout 
the eruption. The goal is to follow all the big and subtle variations 
in exquisite detail so that we can understand their causes...All 
contributing observers will be included as authors of the resulting 
papers..."

Coordinates: RA 09 04 41.5 , Dec -32 22 47.4 (J2000.0)

Charts for T Pyx may be plotted using the AAVSO's Variable Star Plotter: 
http://www.aavso.org/vsp

Please use the current chart which has the most up-to-date comparison 
star magnitudes.

Please promptly submit all observations to the AAVSO International
Database using the name "T PYX".

Thank you in advance for your participation in this very exciting 
campaign and for your contributions to this fundamental research!

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.



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  • » [AZ-Observing] Re: AAVSO Alert Notice 437: Campaign to monitor T Pyx throughout 2011 eruption - Wayne (aka Mr. Galaxy)