(cba:news) southern novae and applicants

Joe Patterson jop at astro.columbia.edu
Tue Jan 14 05:07:02 EST 2014


Yes, T Pyx doesn't seem to need a lot of attention now.  Gordon sent in 
a beautiful run from Siding Spring, which in my mind clinched the main 
points: the light curve has returned to its precise pre-eruption shape 
and period (actually 0.01% longer).

V959 Mon is a very good one for attention.  Last year, Josch, Tom, and 
Mark Wagner nailed down the period: near 7 hours.  But orbital light 
curves (not periods, but light curve shapes) change rapidly over the 
first few years - certainly as a result of the nova's evolution, and 
possibly as a result of the white dwarf's declining 
temperature/luminosity.  Thus the orbital wave's amplitude in energy 
units *might* serve as a bolometer for the white-dwarf luminosity (which 
is not directly observable, because it lies in the unobservable EUV).

HZ Pup really fascinated me, because the light curve and fast period 
seem to be pretty much "standard issue" for intermediate polars... which 
implies that accretion is likely channeled by white-dwarf magnetism 
(assuming the signal is very stable, which it is, so far).  Thus it 
could be a pretty good laboratory for how novae are affected by 
magnetism.  In my opinion, only one other such star is known, V1500 Cyg. 
  As some of you know, there's a lot of enthusiasm out there for 
magnetic novae (led by Brad Schaefer and Marina Orio, and the full list 
is long); but to me the evidence seems very weak, practically 
nonexistent except for V1500 Cyg.  So I'm delighted to find (seemingly)
another... and it raises a host of interesting questions: what else does 
the magnetism do, aside from steer accretion at quiescence? affect the 
nova explosion itself? steer outflowing gas? and so on.  Our data can 
only probe a few such questions, but it's absolutely critical to the 
main question - how solid is the demonstration of that fast stable 
signal which is thought to be the hallmark of magnetism?

I concur that continuous monitoring is the way to go, because the period 
is fast (and flickering is even faster).  So among the Chile telescopes, 
Arto's is the preferred setup.  But V959 Mon is quite a *good* target 
for your telescope, Josch, because the light curve seems to have a 
fairly smooth shape - not a lot of fast activity.  Thus 5-minute 
sampling might be just fine.

AQ Men is not a known nova, but somewhat unique because it seems to have 
an eclipse which comes and goes.  This might be due, e.g., to a 
precessing disk which changes its orientation with respect to us on a 
timescale of a few days (around 4).  Not proven, but pretty interesting.
Considering its dec, I hoped that it could be a great round-the-world 
star.  Unfortunately, nearly all of the year's coverage *so far* comes 
from Josch, and this is awkward because it's hard to evaluate the data 
at lower time resolution without much fast photometry to compare it to.

So I earnestly hope for more AQ Men data from other longitudes... and am 
agnostic about whether AQ Men or V959 Mon is the better choice for your 
telescope, Josch.  I guess that makes me both greedy and indecisive.

Thus conscience does make cowards of us all.

joe

On 1/14/2014 3:24 AM, m31 at telenet.be wrote:
>
> Then it is maybe better Arto concentrating on time series of HZ Pup then me.
> I do cycling between several stars and hence will not get too dense observations. Though I could change if needed. Arto is also correct that presently the weather in San Pedro is on the deteriorating side probably until end of February. So I stick to AQ Men then until further notice.
>
> Regards,
>
> Josch
>
> ----- Original Message -----
> From: "Arto Oksanen" <arto.oksanen at jklsirius.fi>
> To: cba-chat at cbastro.org
> Sent: Tuesday, January 14, 2014 9:04:45 AM
> Subject: Re: (cba:chat) (cba:news) HZ Puppis and V959 Mon
>
> Hi Joe and Josch!
>
> I can do some long high time resolution runs of HZ Pup from Chile if
> desired. A short test run of HZ is in progress right now.
>
> I have done just a few runs per month of T Pyx during the last months. The
> star is behaving well as Joe commented and this is the time of year when
> the weather is not as good as usual in Atacama.
>
> arto
>
>
> 2014/1/14 <m31 at telenet.be>
>
>> Hi Joe,
>>
>> what about stopping of AQ Men?
>> Are you interested in data on HZ Pup from Chile, too?
>> The present full moon is of course challenging with mag 17 and below. I
>> did not do T Pyx as I know that Arto is normally following this star and
>> his location is just 20m from mine.
>>
>> Actually together with Tom K. we observed N Mon 2012 during several nights
>> to get the period of 7h. An ATEL (4803) was published about this.
>> Data can be made available to you if of interest.
>> I am following N Mon 2012 since its eruption with snapshots until today.
>>
>> Also all of those data could be made available. Anyway all data have been
>> submitted to the AAVSO.
>>
>> Regards,
>>
>> Josch
>>
>>
>> ----- Original Message -----

>>>>
>>>> We have found stable 21 minute oscillations in the light curve of the
>> old nova HZ Puppis (1963).  This had been reported by Abbott and Shafter a
>> long time ago (1997), but never studied again or verified - even by them.
>>   Abbott and Shafter are extraordinarily reliable observers... but it was
>> just a conference proceeding, and such things are usually preliminary
>> reports, which are followed by proper scientific papers.  No paper
>> followed, by them or anyone else.  And being a northern guy, there wasn't a
>> lot of chance for me to follow up.  Then we did, a few days ago - and there
>> it was: beautiful 21 min oscillations, just as advertised.
>>>>
>>>> So far our data is only from Kitt Peak, and we desperately need
>> coverage from other longitudes.  With dec=-28 we can't stay on the star
>> very long, so aliasing is rather severe.  This is all the more so because
>> the orbital signal is very weak in this star.
>>>>
>>>> The star is around V=17.2.  Easy for us with a 2.4 m, but the
>> oscillations are usually pretty strong, and our main reliance on
>> off-longitude data is alias rejection.  So long runs at other longitudes
>> would be wonderful!
>>>>
>>>> There's a lot of competition from other southern novae in the Jan-Feb
>> sky.  Namely T Pyx, CP Pup, and V382 Vel.  I *think* we're done with CP
>> Pup.  It's the most mysterious and complex of all CV light curves I've ever
>> seen... and normally I'd be begging for more data.  But I can't imagine
>> getting coverage any better than we had in 2012 and 2013 - so for the
>> moment, it's off the menu, and I have a big homework assignment.  T Pyx is
>> definitely on the menu, and probably V382 Vel (though more on that in a few
>> days).
>>>>
>>>> Let me know if you manage to obtain a good long time series on HZ Pup.
>> This will affect our priorities in the 2.4 m run, since alias-breaking is
>> aided by the *proximity* of data at different longitudes.  Thanks!
>>>>
>>>> joe p

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