J/MNRAS/465/739 Blobs in AT Cnc (Shara+, 2017)
When does an old nova become a dwarf nova? Kinematics and age of the nova shell
of the dwarf nova AT Cancri.
Shara M.M., Drissen L., Martin T., Alarie A., Stephenson F.R.
<Mon. Not. R. Astron. Soc., 465, 739-745 (2017)>
=2017MNRAS.465..739S 2017MNRAS.465..739S (SIMBAD/NED BibCode)
ADC_Keywords: Novae ; Radial velocities ; Interstellar medium
Keywords: techniques: imaging spectroscopy - stars: individual: AT Cnc -
novae - cataclysmic variables - ISM: jets and outflows
Abstract:
The Z Cam-type dwarf nova AT Cancri (AT Cnc) displays a classical nova
(CN) shell, demonstrating that mass transfer in cataclysmic binaries
decreases substantially after a CN eruption. The hibernation scenario
of cataclysmic binaries predicts such a decrease, on a time-scale of a
few centuries. In order to measure the time since AT Cnc's last CN
eruption, we have measured the radial velocities of a hundred clumps
in its ejecta with SITELLE, Canada-France-Hawaii Telescope's
recently commissioned imaging Fourier transform spectrometer. These
range from -455 to +490km/s. Coupled with the known distance to
AT Cnc of 460pc, the size of AT Cnc's shell, and a simple model of
nova ejecta deceleration, we determine that the last CN eruption of
this system occurred 330+135-90yr ago. This is the most rapid
transition from a high mass-transfer rate, nova-like variable to a low
mass-transfer rate, dwarf nova yet measured, and in accord with the
hibernation scenario of cataclysmic binaries. We conclude by noting
the similarity in the deduced outburst date (within a century of
1686 CE) of AT Cnc to a 'guest star' reported in the constellation
Cancer by Korean observers in 1645 CE.
Description:
AT Cnc was observed on 2016 January 9, as part of SITELLE's Science
Verification phase using the SN3 filter (flat transmission above
95 per cent in the 651-685nm range) at a spectral resolution of
R=1300. This spectral region contains the three strongest lines in the
optical part of the ejecta spectrum, due to [NII] and Hα. We
note that these spectra were not intended for, and are not useful for
abundance analyses, as the ejecta of AT Cnc have swept up a mass of
interstellar medium (ISM) that is several times larger than the
original ejecta mass. They are, however, powerful probes of the
kinematics and age of the ejecta.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 39 115 Properties of blobs in AT Cnc
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See also:
J/A+A/564/A31 : SMC blob N26 multiband photometry (Testor+, 2014)
J/ApJ/845/172 : LAE candidates around bright Lyα blobs (Badescu+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/115] Blob sequential number
5 I1 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 14 F5.2 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign (J2000)
17- 18 I2 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 26 F4.1 arcsec DEs Declination (J2000)
28- 31 I4 km/s RV Radial velocity
33- 34 I2 km/s e_RV rms uncertainty on RV
36- 39 F4.1 10-19W/m2 Flux Flux in the [NII] line
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-Jul-2018