From jop at astro.columbia.edu  Mon Feb  8 11:10:30 2021
From: jop at astro.columbia.edu (Joe Patterson)
Date: Mon, 8 Feb 2021 11:10:30 -0500
Subject: (cba:news) HV Cet, HZ Pup, AM CVn... and finis to T Pyx
In-Reply-To: <CALVYL-Dnp4ug96C6R2P9eka31EJyAfm3z8GOOwC0garfkcU0ww@mail.gmail.com>
References: <CALVYL-Dnp4ug96C6R2P9eka31EJyAfm3z8GOOwC0garfkcU0ww@mail.gmail.com>
Message-ID: <7c323cc1-2fa4-2dcb-4d78-d83a78e5128b@astro.columbia.edu>

Hi CBAers,

HV Cet is likely an important star - a possible close cousin to T Pyx. 
It's late in the observing season, and still pretty faint... but our S/N 
standards are relaxed for a star like this, about which we know very 
little.  if you have a clear dark noght, give it a try.  With its dec of 
-5, everyone can likely get a few-hour run (if it's not prohibitively 
faint).

A flurry of attention to T Pyx by Gordon, Berto, Josch, and Peter has 
sewed up that star for the year - we have a very dense 10-day time 
series, and scattered coverage over a couple of months.  The orbital 
period is continuing to increase, though at a somewhat slower rate. 
Nothing more needed.

Among the many novae in Puppis we're observing or considering, HZ Pup is 
the one very near conclusion (that is, our study is).  A good subject 
for February.

In the north, AM CVn is now a good target in the morning sky.  It will 
get better, of course.  Because the periodic signal we care most about 
is the weak ORBITAL signal at 1028 s, quality of night is pretty important.

More, in a day or two.  Enrique, do you have special requests for the IPs?

joe


-------- Forwarded Message --------
Subject: 	[vsnet-chat 8599] HV Cet: long-term brightening (From Gaia alert)
Date: 	Mon, 8 Feb 2021 23:32:55 +0900
From: 	???? <tampo at kusastro.kyoto-u.ac.jp>
To: 	vsnet-chat at ooruri.kusastro.kyoto-u.ac.jp, 
vsnet-task at ooruri.kusastro.kyoto-u.ac.jp



HV Cet: long-term brightening (From Gaia alert)

Gaia alert reported a long-term brightening of a classical nova HV Cet, 
which erupted in 2008.
HV Cet has brightened ~ 2mag in recent half a year.

Gaia21arb, 2021-02-06 12:45:41, type = unknown, RA = 46.494, Dec = 
5.787, Histric mag = 19.27, alert mag = 18.08, amplitude = 1.19,
comment = 2 mag brightening of HV Cet, identified as a nova and 
supersoft source in 2008
http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia21arb/ 
<http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia21arb/>

Brightening is also seen in ZTF broker?lasair.
https://lasair.roe.ac.uk/object/ZTF18acvbjaw/ 
<https://lasair.roe.ac.uk/object/ZTF18acvbjaw/>

Best,
Yusuke
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From jop at astro.columbia.edu  Mon Feb  8 11:47:46 2021
From: jop at astro.columbia.edu (Joe Patterson)
Date: Mon, 8 Feb 2021 11:47:46 -0500
Subject: (cba:news) Fwd: [vsnet-alert 25345] Re: HV Cet: long-term
 brightening (from Gaia alert)
In-Reply-To: <1132488524.2672665.1612801670342@mail.yahoo.com>
References: <1132488524.2672665.1612801670342@mail.yahoo.com>
Message-ID: <f850bd5e-2ba7-d466-fe86-d43ef048bdd7@astro.columbia.edu>

Thanks, Patrick, for that extra info.

joe p


-------- Forwarded Message --------
Subject: [vsnet-alert 25345] Re: HV Cet: long-term brightening (from 
Gaia alert)
Date: Mon, 8 Feb 2021 16:27:50 +0000 (UTC)
From: Patrick Schmeer pasc1312-aavso at yahoo.de via vsnet-alert 
<vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>
Reply-To: Patrick Schmeer <pasc1312-aavso at yahoo.de>
To: vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp, cvnet-outburst at groups.io, 
baavss-alert at groups.io

  HV Ceti
https://www.aavso.org/vsx/index.php?view=detail.top&oid=184509
  During my regular checks of ZTF Lasair data
I had noticed already in 2020 December and
2021 January a somewhat brighter state (also
noticeable in the images on the LASAIR page).
However, judging from Gaia data (made
publicly available only today) a gradual
brightening since 2020 August or September
is evident. According to the latest Gaia and
ZTF observations (obtained on February 6
and 8) HV Cet is now brighter than at the
optical peak (Gmag. 18.5) around 2018
September 16 (see also the links in Y.
Tampo's message below).
  Btw, for the ASAS-SN Sky Patrol (Shappee
et al. 2014ApJ...788...48S and Kochanek
et al. 2017PASP..129j4502K) HV Cet is not
yet bright enough to be detected:
https://asas-sn.osu.edu/sky-patrol/coordinate/aa478dd3-b94b-418b-86c2-3596604130d1
  Follow-up observations are encouraged
(let's see whether this is a new eruption
or not).
  Clear skies,
Patrick
-------
      Am Montag, 8. Februar 2021, 15:33:39 MEZ hat ???? 
<tampo at kusastro.kyoto-u.ac.jp> Folgendes geschrieben:    HV Cet: 
long-term brightening (From Gaia alert)
Gaia alert reported a long-term brightening of a classical nova HV Cet, 
which erupted in 2008.HV Cet has brightened ~ 2mag in recent half a year.
Gaia21arb, 2021-02-06 12:45:41, type = unknown, RA = 46.494, Dec = 
5.787, Histric mag = 19.27, alert mag = 18.08, amplitude = 1.19,?comment 
= 2 mag brightening of HV Cet, identified as a nova and supersoft source 
in 2008http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia21arb/

Brightening is also seen in ZTF 
broker?lasair.https://lasair.roe.ac.uk/object/ZTF18acvbjaw/

Best,Yusuke
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From jop at astro.columbia.edu  Tue Feb 23 13:55:48 2021
From: jop at astro.columbia.edu (Joe Patterson)
Date: Tue, 23 Feb 2021 13:55:48 -0500
Subject: (cba:news) menu for february-march 2021
Message-ID: <43d9505d-e7d7-2b09-400c-b392603d20ec@astro.columbia.edu>

Hi CBAers,

Special interest in these far-southern stars for the next 6 weeks:
NR TrA, WX Cen, IM Nor.  All stars for which we have ongoing 
*orbital-period* studies.  For that reason, time resolution is not so 
important.
Nor is quality of night, if it's decently clear.  LENGTH of run matters; 
 >3 hrs highly desirable.  HZ Pup is still desirable, but we're almost 
finished with it.

In the north, here's the basket of desirables: AM CVn, BH Lyn, V1062 
Tau>  Long-term studies ongoing for all.  AM CVn will especially reward 
*density* of coverage - as much as you can in a few weeks.  (That should 
finish the 30-year study.)    BH Lyn is an orbital + superhump study, so 
will reward length of run.  No special advice re V1062 Tau; we know only 
the broad picture (periodic signals of 1 and 10 hiurs), and seek mainly 
to close the season's coverage of the 1-hour signal.

And four stars pretty close to the celestial equator:
HP Lib - some 2-3 hour runs to start the season.
VZ Sex and WX Pyx - good long runs.
YY Sex - just 2-3 runs through an I or R filter.  Our data show 
abundantly that this star ia misclassified; but to publish it, we need 
to get a very accurate period as well as straighten out the 
classification (AM Her).

I'm not aware yet of the 2021 plans for amateur-astro meetings (mainly 
SAS and AAVSO).  Can someone knowledgeable write to cba-news or -chat 
with this info?

joe


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From jop at astro.columbia.edu  Wed Feb 24 09:21:12 2021
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 24 Feb 2021 09:21:12 -0500
Subject: (cba:news) 2021meetings... and WX Pyx
Message-ID: <2174d08c-1717-a0dd-dd23-5ffdad0d7d0a@astro.columbia.edu>

Hi CBAers,

Thanks, Gordon and Bob, for that info re the 2021 SAS and AAVSO 
meetings.  I certainly plan to attend both... and Bob, it would be good 
to have a breakout session for CBAers at the SAS meeting.  Good chance 
for us all to meet, and for me to hear from you how I can support our 
common enterprise + you personally.  I get a lot of benefit from all 
that data (the NSF loves citizen science)... so lemme know how I can 
support you.

WX Pyx is well placed now in the evening sky.  Much better in the south, 
of course, but the periodic signals are quite strong and the star is a 
suitable target anywhere south of roughly +42 deg.  In particular, we 
could approach round-the-world coverage if we had runs in the western 
USA.  (I'm hoping Gordon and Peter will keep the vigil in Australia, 
too.)  And you can slightly stretch our usual "2.0 airmass" rule - since 
it's *difference* in airmass that hurts, and this star never gets high 
for USA latitudes.***

joe

*** BTW you might ask "why not CORRECT for airmass?".  Since I'm a huge 
fan of long runs, I've experimented a lot with this.  On rare occasions 
I do; an extra (differential) extinction of ~0.1 mag/airmass works 
reasonably for the average CV and the average comp star.  But if you get 
it wrong, then you've basically inserted a periodic signal into the 
data.  So, on the principle "keepen das hands off das blinkenlights", I 
prefer not to mess around with that.
"

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