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Transcient in Cygnus

PostPosted: Fri Jul 12, 2019 11:28 pm
by Francois Teyssier
Discovery at mag 9.2 : PSN J21040470+4631129 2019 07 12.4900* 21 04 04.70 +46 31 12.9 9.2 U Cyg 9 0
by by Hideo Nishimura, Shizuoka-ken, Japan

http://www.cbat.eps.harvard.edu/unconf/followups/J21040470+4631129.html

Image 300 secondes with Echelle spectrograph R = 11000

NovaCyg2019.PNG
NovaCyg2019.PNG (277.41 KiB) Viewed 7701 times


Send spectra to francoismathieu.teyssier at bbox.fr for ATel and inclusion in ARAS database

f

Re: Transcient in Cygnus

PostPosted: Sat Jul 13, 2019 12:11 am
by Francois Teyssier
...

Just a dwarf nova in outburst

tcpj21040470+4631129_20190712_961_fteyssier.png


FWHM (H alpha ) = 330 km/s and 1/2 FWZI = 500 km/s


Dommage

François

Re: Transcient in Cygnus

PostPosted: Sat Jul 13, 2019 2:46 am
by Francois Teyssier
The ATel:
***Instant Email Notice***: Transients

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The Astronomer's Telegram http://www.astronomerstelegram.org

==============================================================================
ATEL #12936 ATEL #12936

Title: Echelle spectroscopy of TCP J21040470+4631129
Author: Francois Teyssier (ARAS Group, Rouen, France)
Queries: shore@df.unipi.it
Posted: 13 Jul 2019; 02:43 UT
Subjects:Cataclysmic Variable, Transient

We report optical echelle spectroscopy (R ~ 11000, 4100-7300A) the newly
reported transient TCP J21040470+4631129 (discovered on 2019 Jul.12.190
UT by Hideo Nishimura). The spectrum is consistent, obtains on 2019 Jul
12.9 UT (exposure time of 2589 sec, S/N ~ 40 hat 6100 A). The spectrum
is consistent with a large amplitude outburst of a cataclysmic variable.
The He I lines (e.g. 4471, 5013, 5876, 6678, 7065) all show symmetric
double peaks with separation 210 km/s (HWZI ~ 540 km/s). He II 4686 shows
peak separation of 310 km/s (but with there are also weak peaks coincident
with the He I lines) and broader wings, HWZI ~ 700 km/s; the redshifted
peak (+130 km/s) is slightly stronger and narrower. The profiles are centered
at 12 km/s but the wings show asymmetric extensions. The H-alpha and H-beta
profiles are asymmetric (R/V peak ~ 1.14±0.05) with separation of 160
km/s (HWZI = 600 km/s). There may be an absorption component at -30 km/s
(a similar minimum is seen on the He I lines) and H-beta and H-gamma show
an underlying broad absorption line that is redshifted relative to the
emission component by about 150±50 km/s, based on the profile asymmetry.
Additional emission includes the C III lines as a broad, featureless profile.
The precursor candidate noted in the CBAT report coincides with Gaia (DR2)
2163612727665972096 with parallax 9.134+/-0.116 (g=17.77 mag)

ARAS Spectral Database: http://www.astrosurf.com/aras/Aras_Data ... taBase.htm
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Password Certification: S. N. Shore (shore@df.unipi.it)
http://www.astronomerstelegram.org/?read=12936
==============================================================================

Re: Transcient in Cygnus

PostPosted: Sat Jul 13, 2019 8:01 am
by Tim Lester
My spectrum from a little later the same night.

tcpj21040470+4631129_20190713_176_tlester_1.png

tcpj21040470+4631129_20190713_176_tlester_2.png

tcpj21040470+4631129_20190713_176_tlester_3.png


Tim

Re: Transcient in Cygnus

PostPosted: Sat Jul 13, 2019 10:00 pm
by Francois Teyssier
Impressive changes in a few hours
tcpj21040470+4631129_Ha.png
tcpj21040470+4631129_Ha.png (14.21 KiB) Viewed 7538 times

Re: Transcient in Cygnus

PostPosted: Sun Jul 14, 2019 12:08 am
by Paolo Berardi
Great observations and reactivity! Not a classical nova but I've never seen such a bright cataclysmic outburst!

A fresh spectrum with Lhires III 2400 (R~16000). Mag V ~9.1

Image

A lot of change...

Paolo

Re: Transcient in Cygnus

PostPosted: Sun Jul 14, 2019 9:35 am
by Robin Leadbeater
Paolo Berardi wrote:Not a classical nova but I've never seen such a bright cataclysmic outburst!


Indeed! Are there other examples where the H alpha emission in a dwarf nova outburst completely dominates the absorption like this ? (an asymmetry and line of sight effect ?)

Cheers
Robin

Re: Transcient in Cygnus

PostPosted: Sun Jul 14, 2019 9:50 am
by David Boyd
Spectrum of TCP J21040470+4631129 taken on 13th July with a LISA spectroscope (R=1100) on a C11 and flux calibrated with concurrently measured mean magnitude V=9.14, B-V=-0.23.

tcpj21040470+4631129_20190713_928_D.Boyd.png
tcpj21040470+4631129_20190713_928_D.Boyd.png (26.47 KiB) Viewed 7483 times

David

Re: Transcient in Cygnus

PostPosted: Sun Jul 14, 2019 6:13 pm
by Francois Teyssier
Nice spectrum, David

Robin:
To my knowledge, this is the first time we get high res spectra of a DN in outburst
The change of the profiles reflect probably the orbital motion of the hot spot.
The profile is the combination of the disk in itself (about 20000 K) and the hot spot.

f

Re: Transcient in Cygnus

PostPosted: Sun Jul 14, 2019 8:06 pm
by Robin Leadbeater
Hi Francois,

The line profile of the He II 4686 line might be interesting to follow. According to this paper it is associated with spiral structure in the disc
https://academic.oup.com/mnras/article/ ... 14/1079544

Cheers
Robin