Keith g
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Loc: Waterford/Cavan Ireland
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AAVSO Special Notice #22
Bright New Variable in Cassiopeia
(October 31, 2006)
Daniel W. E. Green, Central Bureau for Astronomical Telegrams, reports
(Central Bureau Electronic Telegram 711) that S. Nakano, Sumoto, Japan,
reports the discovery of a brightening star in Cassiopeia by Akihiko Tago,
Ayabe, Tsuyama, Okayama-ken, Japan. Unfiltered CCD observations by Tago
include October 25.538 UT, 10.7; 27.409, 10.5; 30.411, 8.8; 31.469, 7.5.
Tago used a 70-mm f/3.2 lens and a Canon EOS 20Da digital camera (limiting
magnitude 12).
Tago adds that a star of magnitude 11.8, which did not show variability in
his earlier images and which he identifies as GSC 3656-1328, is located very
close to the new object's position of:
R.A. = 00h 09m 21.81s, Decl. = +54o 39' 43.8" (2000.0)
According to Green, apparently the GSC star is the same as listed in the
USNO-A2 catalogue as 1425.00229853, having position end figures 22.00s, 44.0"
and blue and red magnitudes 11.9 and 11.3, respectively.
A search at AAVSO of SIMBAD, the GCVS+NameLists, and VSX showed nothing
variable close to the position of the new object.
Visual, PEP, and CCD coverage is requested; photometric observers should
use a V filter if possible.
The position of the object lies within the field of the 'a' scale AAVSO
chart for R Cas. The comparison star magnitudes on this chart go to 7.5,
so they may be used while the object is so bright. The chart is at:
http://www.aavso.org/cgi-bin/searchcharts3.pl?name=r%20cas
Please report observations to the AAVSO as: 0004+54B VAR CAS 06. Also, be
sure to indicate what chart/comparison star(s) you used.
Congratulations to Akihiko Tago on his latest discovery!
This special notice was compiled by: Elizabeth O. Waagen
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ph2
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Reged: 11/28/05
Posts: 111
Loc: Aalborg, Denmark
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That is a (possible) Nova blazing at magnitude 8 close to the W-pattern of Cassiopeia! 
OK, it is only a mag. 9 object : VAR CAS 06
Edited by ph2 (11/01/06 01:02 PM)
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Keith g
sage
Reged: 02/13/05
Posts: 329
Loc: Waterford/Cavan Ireland
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It's reported to be fading very fast at a rate of 0.06-0.07 magnitude per HOUR!
Proably an (Na) type nova??
Keith..
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5402
Loc: London UK
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...this is my wideangle shot from this evening Nov 1. The star is fainter than I was given to understand from initial reports. My lo-res spectrum of the star shows no emission lines characteristic of novae but weak Halpha/ beta/gamma in absorption like an A-type star. The star is bluish in my colour image which suggests an early B-A-F type spectrum.
--------------------
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My observatory build-ETX-70 imaging-my videos
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nytecam
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...and one from tonight [Nov 2] - RH side with exagerated colour saturation that's a fair match for the stars' colour index quoted in Cartes du Ciel using Tycho catalogue for stars of similar brightness 
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Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+DS-2090+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Low resolution spectra taken over the past 3 nights show typical A/F class spectral features and no emission lines
http://mysite.wanadoo-members.co.uk/astro2/spectra_30.htm
Robin
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Modified web and video cams, Spectrograph
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Psion
professor emeritus
Reged: 04/27/05
Posts: 671
Loc: Czech Republic, Prague
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It looks like a typical B9.5 spectrum!
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Newton 200/800, 200/1200, 100/1000
Sky-Watcher ED80 + mount CG5 GT
PENTAX 75 SDHF
Mount Celestron CGE
Meade LX200R 8" OTA
EOS 300Da, SBIG ST-402ME, SBIG ST-2000XM
Spectrograph SBIG DSS-7, LHIRES III
Mintron 12V1C-EX modif (amp off)
http://astroview.psionfired.com
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Quote:
It looks like a typical B9.5 spectrum!
comparing to library spectra and trying to get the best fit to the continuum, I made it a bit cooler, perhaps A3 but I am no expert that is for sure!
Robin
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Psion
professor emeritus
Reged: 04/27/05
Posts: 671
Loc: Czech Republic, Prague
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I will make (next weekend) a spectrum with the DSS-7 and 8" LX200R and I will send result. Did you use software VSPEC? Maybe you can try normalization and calibration in this SW?
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Newton 200/800, 200/1200, 100/1000
Sky-Watcher ED80 + mount CG5 GT
PENTAX 75 SDHF
Mount Celestron CGE
Meade LX200R 8" OTA
EOS 300Da, SBIG ST-402ME, SBIG ST-2000XM
Spectrograph SBIG DSS-7, LHIRES III
Mintron 12V1C-EX modif (amp off)
http://astroview.psionfired.com
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Yes I used vspec. the spectra are fully calibrated (linearised/darks/flats/background subtraction) Calibrated for wavelength and for instrument response and atmospheric extinction (though the telluric lines have not been subtracted) using the spectrum of nearby Delta Cas taken during the same run.
I hope you can get enough light for the DSS-7 It is already down below mag10 I have not bothered trying with my LHIRESIII
Robin
--------------------
Vixen VC200L GPDX Skysensor 2000
Modified web and video cams, Spectrograph
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5402
Loc: London UK
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Quote:
I will make (next weekend) a spectrum with the DSS-7 and 8" LX200R and I will send result. Did you use software VSPEC? Maybe you can try normalization and calibration in this SW?
That's great - we await your results 
--------------------
Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+DS-2090+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
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nytecam
Postmaster
Reged: 08/20/05
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Excellent result Robin but we'll have to watch our backs 
--------------------
Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+DS-2090+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
Starlight SXVF_M9/Lodestar/Canon 300D DSLR/Fuji E550
My observatory build-ETX-70 imaging-my videos
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Professionals now confirm a type A spectrum with no emission lines (CBET 718. Second hand from AAVSO-DIS as I do not subscribe)
It looks like this could be something rather unusual.
I took another spectrum last night but rather noisy as the clouds rolled in. The run of good weather has broken here :-(
Robin
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Vixen VC200L GPDX Skysensor 2000
Modified web and video cams, Spectrograph
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Anonymous
Unregistered
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Here is some images;
http://sabbe.fragzone.se/KPO/gsc36561328.htm
Last night i get it at mag 10.52CV
this morning it seems to be around 10.70
h-g
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Keith g
sage
Reged: 02/13/05
Posts: 329
Loc: Waterford/Cavan Ireland
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From the Astronomer Telegram - A Microlensing Event??
Keith..
ATEL #931 ATEL #931
Title: The bright new variable in Cassiopeia - a microlensing event?
Author: M. Mikolajewski, T. Tomov, A. Niedzielski, K. Czart, C. Galan
- Torun Center for Astronomy, Nicolaus Copernicus University, 87-100
Torun, Poland
Queries: aniedzi@astri.uni.torun.pl
Posted: 3 Nov 2006; 20:56 UT
Subjects: Optical, Microlensing Events, Variables, Stars
We report BV photometry and optical spectroscopic observations of a bright
new variable in Cassiopeia, identified as GSC 3656-1328 (CBET # 711,
# 712). According to SIMBAD database GSC 3656-1328 is a 11.4 star in
V with B-V of about 0.2. Our spectra in the region 3700-7300AA and
at a resolution of 4A were obtained with the 60/90cm Schmidt-Cassegrain
telescope of Torun Observatory between 2006 November 02.790 UT and November
03.713 UT. They show a typical A0V-A1V star without remarkable spectral
variations or line shifts. The Balmer absorptions show an average radial
velocity of -45 +/-15 km/s. The brightness estimate: V=10.15 and B=10.35
was obtained with the 60cm Cassagrain telescope of Torun Observatory
on 2006 November 02.765 UT. The SIMBAD data show that before the event
GSC 3656-1328 was a slightly reddened A0V-A1V star at a distance of
about 1 kps. The only observed change was a sudden rapid increase and
then a decrease of the brightness with an amplitude about 4 mag without
any spectral changes. It is difficult to associate such an observed phenomenon
with any type of variable stars. A possible explanation of the GSC 3656-1328
behavior could be a gravitational microlensing event. If that is the
case, this would be the closest microlensing event ever observed.
------------------------------------------------------------------------------
Password Certification: Andrzej Niedzielski (aniedzi@astri.uni.torun.pl)
http://www.astronomerstelegram.org/?read=931
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Well that would certainly explain the lack of change in the spectrum. A0-1v eh ? Oh well, I was pretty close :-)
Robin
--------------------
Vixen VC200L GPDX Skysensor 2000
Modified web and video cams, Spectrograph
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5402
Loc: London UK
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Quote:
Well that would certainly explain the lack of change in the spectrum. A0-1v eh ? Oh well, I was pretty close :-) Robin
That's my first [possible] microlensed spectrum too
--------------------
Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+DS-2090+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
Starlight SXVF_M9/Lodestar/Canon 300D DSLR/Fuji E550
My observatory build-ETX-70 imaging-my videos
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Anonymous
Unregistered
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Hi all,
is it any of you witch have get some images on the mystery star in Cassiopeia, I am very interested of some copies from 2006-11-04/2006-11-05.
Hans-Göran
http://swedbirdastro.proboards70.com/index.cgi
http://sabbe.fragzone.se/KPO/gsc36561328.htm
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Keith Schlottman
member
Reged: 10/02/05
Posts: 49
Loc: Tucson, AZ
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Last night I attempted to obtain a spectrum of GSC 3656:1328 using an SBIG SGS and a 12" LX200GPS. This was a very challenging object for me to obtain a spectrum on since I've only been using this system for about a month and until now I've only been working on brighter stars.
I set the scope up at a temporary location and didn't do a drift alignment so my tracking was less than ideal. I took 9 x 10 minute exposures and the star was definitely not on the slit the whole time. A great deal of sky glow shows up in the spectrum and the signal was rather weak. This plot is from a median combine of the dark-subtracted 9 images, and while I don't find it very impressive, maybe someone can extract something useful out of it.
I spent today observing the Mercury transit and need to get some sleep before driving to AIC tomorrow, so I have not had time to really try to get the most out of the data, nor have I worked on line identification. Other than wavelength and ccd response calibrations I have not done much with it. But since I was asked to obtain this I wanted to get it posted asap in case it will prove helpful to some of you experts out there. I'm willing to try this one again next week (weather permitting of course) to see if I can improve on it, if anyone would like. I could also try it in high resolution mode if there is a portion of the spectrum that someone would like to narrow in on.
Clear Skies,
Keith Schlottman
--------------------
---------------------------------
Wishing you the Clearest of Skies
Xanadu Observatory
http://www.xanaduobservatory.com
---------------------------------
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Hi Keith,
This is potentially an extremely intersting spectrum as it appears to show several emission lines which might support the nova theory against the gravitational microlensing. Is there any possiblity of these being artifacts eg interfering stars (Did you run the SGS with or without the slit?)
Robin
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Vixen VC200L GPDX Skysensor 2000
Modified web and video cams, Spectrograph
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Keith,
I see you mentioned sky glow. Could the emission lines be from the background? Do you have a spectrum of the background for comparison, eg taken from a position on the slit away from the star spectrum?
Robin
EDIT
Christian Buil's page here shows examples of skyglow spectra
http://www.astrosurf.com/buil/us/spe2/hresol4.htm
It looks like the emission lines may match Hg and Na lines from street lamps
Robin
--------------------
Vixen VC200L GPDX Skysensor 2000
Modified web and video cams, Spectrograph
Edited by robin_astro (11/09/06 09:19 AM)
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5402
Loc: London UK
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Quote:
Keith,I see you mentioned sky glow. Could the emission lines be from the background? Do you have a spectrum of the background for comparison, eg taken from a position on the slit away from the star spectrum? Robin
EDIT Christian Buil's page here shows examples of skyglow spectra
http://www.astrosurf.com/buil/us/spe2/hresol4.htm
It looks like the emission lines may match Hg and Na lines from street lamps Robin
A great and worthy spectrum Keith - many thanks for putting in the effort. The Balmer series of hydrogen [absorption] lines is evident but no H-a in emission typical for a novae event - it's probable the emission lines are from emission lamps via distant light pollution which curiously Mt Wilson used decades ago to calibrate their spectra
--------------------
Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+DS-2090+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
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My observatory build-ETX-70 imaging-my videos
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Keith g
sage
Reged: 02/13/05
Posts: 329
Loc: Waterford/Cavan Ireland
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Keith, could you report your results to any of the following?
There's a lot of activity at the moment, and all data would be very valuable. We're all one big group here...
Keith..
<cvnet-discussion@yahoogroups.com>
<baavss-alert@yahoogroups.com>
<aavso-discussion@aavso.org>
<variable_star_forum@yahoogroups.com>
<vsnet-obs@kusastro.kyoto-u.ac.jp>
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Keith Schlottman
member
Reged: 10/02/05
Posts: 49
Loc: Tucson, AZ
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Hello Robin, Maurice, and Keith,
thanks for the comments. Yes, much of the spectra was contaminated by skyglow. I've done a little more work on the spectra tonight, but I drove 13 hours today from Tucson to San Jose so I'm a bit weary, so there may be more needed.
I went back to the median combination and used Iris to rotate and tilt in order to get the lines vertical. Then I subtracted the Sky, again in Iris. Then I brought the result into Visual Spec, wavelength calibrated, and flux calibrated. The result is below.
I also cropped the results from Iris and used Photoshop's motion blur to expand the image vertically, and used curves and levels to enhance the contrast. Note that I did this _after_ producing the plot, not before. The result is also below.
As noted the Balmer series is evident. I'm not sure about the rest. Particularly I note the emission line at 4983.85 and 5861.44, and 6221.34 (as determined in vSpec). I looked in the elements table in vSpec and noted that TI is at 4981.73 and 6221.41, and TiO is at 5862; is this simply a coincidence? I don't see matching Telluric lines on Christian's site.
I also cannot explain the apparent ~ level intensity (and even a hump between ~ 4900 and 6300 A) which does not seem normal for an A-type star. I wonder if this is an artifact of the Iris processing, which may have resulted in some zero value data being averaged in?
I suspect this project has more to it, and will appreciate any assistance & comments you may have...
Clear Skies,
Keith Schlottman
--------------------
---------------------------------
Wishing you the Clearest of Skies
Xanadu Observatory
http://www.xanaduobservatory.com
---------------------------------
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Keith Schlottman
member
Reged: 10/02/05
Posts: 49
Loc: Tucson, AZ
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Almost forgot, Keith, thanks for the tips on who to share the data with. I will try to do that tomorrow, other than the AAVSO I'm not subscribed to any of those so I may need to join them first.
Keith Schlottman
--------------------
---------------------------------
Wishing you the Clearest of Skies
Xanadu Observatory
http://www.xanaduobservatory.com
---------------------------------
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Keith Schlottman
member
Reged: 10/02/05
Posts: 49
Loc: Tucson, AZ
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Maybe there is more to this story.
Before I went to sleep last night I was reading Kaler's "Stars and Their Spectra". On page 236 he talks briefly about spectra of stars in Nova. He says that their spectra experience a blueshifting. Kaler also mentions emission lines but it's not clear which emission lines occur.
Well, when I originally calibrated GSC3656:1328 against a Hydrogen lamp spectra which was taken immediately prior, the spectrum was blueshifted. I thought it was just an error so instead I calibrated on known H-a and H-B lines. However, when I calibrated the spectrum of Caph against the H lamp (I took Caph to establish my ccd response, also just prior to the GSC spectra), its lines were _not_ blueshifted; the lined up perfectly.
So, perhaps the spectrum really is blueshifted. I went back and re-calibrated the spectrum for wavelength against the H lamp. I also reprocessed Caph using the same methods (i.e. slant & tilt & sky subtraction in Iris), and re-calibrated it in vSpec. I double-checked the new Caph spectrum against the previous Caph spectrum and it did not show any noticeable change.
My revised GSC3656:1328 spectrum shows H-alpha at 6539.96, implying a blueshift of about 22.89 Angstroms (but resolution is only 4.29 Angstroms in low-res mode).
This changes the peaks of the emission lines that I mentioned in last night's post to approximately 4953.76, 5836.84, and 6201.21 respectively. Again, I do not see a match to Telluric lines upon a quick comparison to Christian's website. I checked vSpec's elements list and I also don't see any common element at or near these wavelengths.
One last comment, Robin you asked was I slit-guiding, yes I was. I watched the screen during data acquisition and I'm confident there were not any other stars that wandered into the slit during the exposures.
So, here is yet another revised spectrum:
--------------------
---------------------------------
Wishing you the Clearest of Skies
Xanadu Observatory
http://www.xanaduobservatory.com
---------------------------------
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robin_astro
super member
Reged: 12/18/05
Posts: 137
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Hi Keith (s)
Wow you have been working hard after your trip!
I am a long way from being an expert on calibrating these types of spectra (I am only slowly getting to grips with my LHIRS III. It might be worth putting the problem to the spectro-l Yahoo groups though.
On the subject of novae and emission lines I believe H or He are the main ones seen with smaller ones eg from Fe etc. I think the blue shift Kaler mentions relates to the blue shifted absorption line which appears with an emission line in the expected place, making a P Cyg type line profile. eg
http://pleione.asu.cas.cz/~slechta/nova/v838m1.gif
There seems to be no sign of the H emission components in this case though.
robin
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Vixen VC200L GPDX Skysensor 2000
Modified web and video cams, Spectrograph
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