From jop at astro.columbia.edu  Sat Aug  1 06:33:02 2020
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sat, 1 Aug 2020 06:33:02 -0400
Subject: (cba:news) August stars, redux... plus CI Aql and the nova project
In-Reply-To: <726475cc-f2e1-8f4e-e012-320ec32f0a88@globetrotter.net>
References: <726475cc-f2e1-8f4e-e012-320ec32f0a88@globetrotter.net>
Message-ID: <18a339c7-f342-95b7-550a-0d19292ed09e@astro.columbia.edu>

Oops, the eyes are not what they used to be!... and they were never that 
good anyway.  As Damien suspects, the proper names are FO Aqr and V1223 
Sgr. Good to know someone has high standards (evident in his photometry 
too).

Also, I omitted one critical star, which I would rate as the highest 
priority for August-September observing: the recurrent nova CI Aql.  I 
stopped thinking about this star years ago, after learning that its 
orbital period is long (~16 hours).  But others, wiser than I, 
recognized that as far as recurrent novae are concerned, it's definitely 
in the "short Porb" class.  Eclipsing too, and on the celestial equator. 
Those should award very high CBA points.  So it really should be one of 
our faves, and now is the season.  I'm really eager to see CBA data on it.

While long observations are very desirable for this 16-hour star, don't 
get too frisky with airmass (i.e., you probably should observe the 2.0 
airmass limit).

We'll be getting some interesting papers out on "old novae" this year, 
and it would be good to start thinking about light curves of "old novae" 
(long past outburst).  Now that ASAS-SN, ZTF, etc. are revealing so many 
dwarf novae, the novae are getting somewhat neglected.  Since each nova 
takes years to play out its particular messages, while each dwarf nova 
is a matter of days-to-weeks, that's understandable.  But in my opinion, 
the incremental knowledge we get from novae is now much higher (per 
observing hour, say)  As the seasons march on, I'll discuss priorities 
re nova targets.

Koji Mukai has a very famous online bible for intermediate polars, and 
recently updated one on recent novae too:

https://asd.gsfc.nasa.gov/Koji.Mukai/novae/novae.html

Only a few of these stars will ever graduate to become CBA targets - 
they're typically quite faint, in Sco-Sgr, highly reddened, etc.  But 
for those special interest in novae, this belongs as one of the revered 
texts.

joe



-------- Forwarded Message --------
Subject: Re: (cba:news) august stars
Date: Fri, 31 Jul 2020 15:36:19 -0400
From: Damien Lemay <damien.lemay at globetrotter.net>
To: Joe Patterson <jop at astro.columbia.edu>

Hi Joe,

Two questions:

1- Could it be FO Aqr instead of FQ Aqr (type PVTELI)?

2- V1223 --- from which constellation?

Damien


On 2020-07-30 9:01 a.m., Joe Patterson wrote:

> 2. Intermediate polars (DQ Her stars).? Right up our alley to measure 
> period change, since we have baselines of 5-20 years.? The ones needing 
> just occasional observation are FQ Aqr and AO Psc. 

V1223 is more
> interesting since it has been much more active this year, and a 
> still-unsettled question is the connection between brightness and period 
> change.? It will take some patience to settle this.
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From jop at astro.columbia.edu  Sun Aug 16 18:18:00 2020
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 16 Aug 2020 18:18:00 -0400
Subject: (cba:news) eclipse timings... and old novae
Message-ID: <d90cbc2c-d38e-fdbc-7ef1-6081ef85dfe0@astro.columbia.edu>

Hi CBAers,

Some general comments about target choices and observing.  As most of 
you realize, we're not doing much with dwarf novae any more.  We're 
still very solicitous about intermediate polars, and trying to 
accumulate long-term observations of all that don't pose some obvious 
practical problems (too faint, crowded field, etc.)  Koji Mukai's 
website is the go-to place for the list + lots more, and his list by RA 
is useful to figure out what's up each month:

https://asd.gsfc.nasa.gov/Koji.Mukai/iphome/iphome.html

Along with Enrique, I'll keep you apprised of which ones we recommend in 
a given season... though you might well want to adopt a specific star 
and just pound on it.  If the star is brighter than ~17.5, You can be 
99% sure you're getting the best coverage of anyone (in the world),
because real ephemeris work has fallen out of favor - professional 
astronomers just can't get the telescope time any more.

But I've gotten fascinated by a new project: tracking the evolution of 
the orbital light curve of old novae.  We've discovered the "quiescent" 
orbital light curves of T Pyx and IM Nor, and tracked their period 
changes - large! - over ~20 years.  And we have (more sparsely) done 
this for ~10 other novae.  The similarities among them are amazing... 
and this too is a project tailor-made for amateur astronomers, because 
professionals often take the view "after you've observed something once, 
why would you do it again?.

So let the word go forth: work on orbital light curves.  Around ~40 
orbits of good data will give an excellent yearly light curve.  You can 
scatter it throughout, although there is always an advantage in doing it 
in a compressed interval (say over a month or two).

The *shapes* in the orbital waveform are of great interest, but the ones 
that show eclipses (or distinct, possibly deep minima in the light 
curve) are usually of greatest interest.  That's where it's advantageous 
to use Enrique's, or Tonny's, or your own calculation of expected time 
of minimum.  It's true - the eclipse phase is the most interesting time. 
  But don't get too fine with this!!  CVs will dish out dirt if you 
start expecting  them to behave as expected.

Seasonally appropriate Stars in this category are CI Aql*, Nova Sco 
1437*, V728 Sco, V392 Per, QR And, V1494 Aql, V1974 Cyg, and V339 Del.
Asterisk means: especially these.

More on the IPs tomorrow... although Enrique's choices are ideal.

joe
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From jop at astro.columbia.edu  Sun Aug 23 10:17:21 2020
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 23 Aug 2020 10:17:21 -0400
Subject: (cba:news) V392 Per... and CI Aql
Message-ID: <3ce6312d-4240-38ce-6f9f-aead792e1452@astro.columbia.edu>

Hi CBAers,

Joe Ulowetz's recent (this week) photometry suggests that this obscure 
star in Perseus - before its 2018 nova event - is flashing a T-Pyx-like 
short-period (orbital?) signal at us.  That would be mighty nice, and 
the star has arrived back in the morning northern sky for decently long 
morning runs.  I believe that there is a companion about 8 arc-sec away, 
so be mindful of that hazard.  Otherwise, it seems to be an ideal 
target, at about magnitude 15 and likely giving good clues on what novae 
do a few years after eruption.  (A phase for which there is not a whole 
lot of compelling evidence.)

We have a pretty good month-long campaign going on another od nova, CI 
Aql. This one is a fully (OK, almost fully) credentialed  cousin of T 
Pyx; and indeed, its light curve looks similar too.  However, its 
near-equatorial location and long Porb (15 hours) means that no one can 
actually record an orbit - or anything close - in one night.  So it's a 
tad difficult to piece together relatively short light curves - because 
of the inevitable night-to-night erratic variability.  See if you can 
get some 5- and 6- hour light curves, and if they were patched pretty 
close together in time, so much the better.

We have a paper on IM Nor (a T Pyx clone) almost ready to ship, and it 
includes analysis and long-term records on V617 Sgr (nominally a V Sge 
star) and QR And (nominally a supersoft).  Presented together because in 
my view, these are basically the same type of star - a massive WD 
accreting at a very high rate.  So those stars are OFF THE TARGET LIST 
until February at least.  I'll send the draft around in a few weeks 
(sooner if you're vitally interested).

joe p
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From jop at astro.columbia.edu  Sun Aug 23 15:43:55 2020
From: jop at astro.columbia.edu (Joe Patterson)
Date: Sun, 23 Aug 2020 15:43:55 -0400
Subject: (cba:news) and V Sagittae, also finis
Message-ID: <0b636d16-bc1f-857a-8847-c75c0cdcef8c@astro.columbia.edu>

  Sorry, I meant to include V Sge and WX Cen also as done for the year, 
after great coverage by CBAers`.  All these closely related stars: IM 
Nor, V Sge, QR And V617 Sgr - all finished for the calendar year.  If 
not longer.  Thanks for all your faithful coverage!

joe p
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From jop at astro.columbia.edu  Fri Aug 28 04:20:45 2020
From: jop at astro.columbia.edu (Joe Patterson)
Date: Fri, 28 Aug 2020 04:20:45 -0400
Subject: (cba:news) ATO J104.6895+17.0332: possible recovery of the 1892
 nova? (=NSV 3313)
In-Reply-To: <E1kBTqd-0000Ae-Rq@ori.kusastro.kyoto-u.ac.jp>
References: <E1kBTqd-0000Ae-Rq@ori.kusastro.kyoto-u.ac.jp>
Message-ID: <5a2361a4-fc8b-6db3-9333-6f97a8b191d0@astro.columbia.edu>

Hi CBAers,

As usual, a nice piece of detective work by Taichi.  A tad too early in 
the season, but... if you have a clear view to the east, put it on your 
list!  Exploring these OLD "old novae" (or in this case, candidates) is 
one of our ongoing high-priority subject areas.

Speaking of which, V Per (1887 nova) is another, much better placed for 
the borealites among us.  It's quite faint (18.5?) but the two things 
we're interested in (orbital waveform and eclipse timing) are not 
terribly demanding.  The eclipses are pretty deep (20th mag?) but fear 
not - with P~2 hour, there are a lot of them, and one can use the 
waveform near eclipse (rise/fall) to define mid-eclipse with passable 
accuracy.

CI Aql and Nova Sco 1437 also continue to be high-priority targets, 
still seasonally appropriate.

joe p

-------- Forwarded Message --------
Subject: [vsnet-alert 24603] ATO J104.6895+17.0332: possible recovery of 
the 1892 nova? (=NSV 3313)
Date: Fri, 28 Aug 2020 11:10:35 +0900
From: Taichi Kato <tkato at kusastro.kyoto-u.ac.jp>
To: variable_star_forum at yahoogroups.com, 
vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp, vsnet-alert at yahoogroups.com

ATO J104.6895+17.0332: possible recovery of the 1892 nova? (=NSV 3313)

ASAS-SN data:
https://asas-sn.osu.edu/light_curves/4ff95625-bc9b-445a-916b-a04de64980c9

    I found a period of 0.477906(2) d with minima of
different depths in one cycle.

Gaia:
065845.488 +170159.74 (2000.0) Gaia_DR2_3361199697425899008 
plx=0.164(0.065) dismod=13.9 pmra=-0.029(0.121) pmdec=-1.322(0.097) 
G=15.604 BP=15.760 RP=15.355

    The Gaia color is too blue for a W UMa star.

Also detected as a variable:
065845.4 +170159 (2000.0) PS1RRJ065845.48+170159.8 RR g=15.21(0.47) 
P=0.31424 0.03/0.32
    The location is sufficiently close to the suspected
nova in 1892 and this object would be the quiescent
counterpart.  Spectroscopy is desired.

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