J/ApJ/773/55 Light curve of T Pyx from 1890 to 2011 (Schaefer+, 2013)
The 2011 eruption of the recurrent nova T Pyxidis: the discovery, the
pre-eruption rise, the pre-eruption orbital period, and the reason for the long
delay.
Schaefer B.E., Landolt A.U., Linnolt M., Stubbings R., Pojmanski G.,
Plummer A., Kerr S., Nelson P., Carstens R., Streamer M., Richards T.,
Myers G., Dillon W.G.
<Astrophys. J., 773, 55 (2013)>
=2013ApJ...773...55S 2013ApJ...773...55S (SIMBAD/NED BibCode)
ADC_Keywords: Novae ; Photometry, UBVRI
Keywords: novae, cataclysmic variables; stars: individual: T Pyx
Abstract:
We report the discovery by M. Linnolt on JD 2455665.7931 (UT 2011
April 14.29) of the sixth eruption of the recurrent nova T Pyxidis.
This discovery was made just as the initial fast rise was starting, so
with fast notification and response by observers worldwide, the entire
initial rise was covered (the first for any nova), and with high time
resolution in three filters. The speed of the rise peaked at 9mag/day,
while the light curve is well fit over only the first two days by a
model with a uniformly expanding sphere. We also report the discovery
by R. Stubbings of a pre-eruption rise starting 18 days before the
eruption, peaking 1.1mag brighter than its long-time average, and then
fading back toward quiescence 4 days before the eruption. This unique
and mysterious behavior is only the fourth known (with V1500 Cyg,
V533 Her, and T CrB) anticipatory rise closely spaced before a nova
eruption. We present 19 timings of photometric minima from 1986 to
2011 February, where the orbital period is fast increasing with
P/dot¶=+313000yr. From 2008 to 2011, T Pyx had a small change in
this rate of increase, so that the orbital period at the time of
eruption was 0.07622950±0.00000008 days. This strong and steady
increase of the orbital period can only come from mass transfer, for
which we calculate a rate of (1.7-3.5)x10-7M☉/yr. We report
6116 magnitudes between 1890 and 2011, for an average B=15.59±0.01
from 1967 to 2011, which allows for an eruption in 2011 if the blue
flux is nearly proportional to the accretion rate. The
ultraviolet-optical-infrared spectral energy distribution is well fit
by a power law with fν∝ν1.0, although the narrow
ultraviolet region has a tilt with a fit of fν∝ν1/3.
Description:
Schaefer has returned to the Harvard College Observatory and
remeasured the many archival photographic plates, with this providing
the photometric history of T Pyx from 1890 to 1953 and the basis for
knowing that T Pyx has suffered a severe decline in quiescent
brightness from 1890 to present.
Starting in 1996, Stubbings began a monitoring program on T Pyx,
accumulating 2004 visual estimates of T Pyx. In his 15yr of seeking
the next eruption, T Pyx was checked more frequently than once every
two nights, all visually with the AAVSO sequence and a 16 inch
Newtonian reflector telescope from Tetoora Road Observatory.
Starting in early 2003, Dillon began a long-term monitoring campaign
on T Pyx, accumulating 125 magnitude estimates before the start of the
eruption. These magnitudes were taken with a CCD camera through a V
filter with the AAVSO sequence of comparison stars.
Starting in 2009 March, Linnolt included T Pyx in his program. His
observations were from several sites on different islands in the
Hawaiian Islands.
From 2005 to 20011, Schaefer has used the SMARTS telescopes on Cerro
Tololo to monitor the slowly fading quiescent magnitude of T Pyx.
From 2010 July until the eruption, ASAS covered T Pyx frequently as a
regular part of its sky survey. ASAS uses a telescope with a 200mm
diameter f/2.8 lens located at the Las Campanas Observatory in
northern Chile.
On five nights in 2008 January, Richards made long time-series
photometry on T Pyx, all with 100s integrations on a 0.41m
Ritchey-Chretein reflecting telescope at Pretty Hill Observatory near
Melbourne, Australia. The images were all taken with an unfiltered
CCD, with the T Pyx magnitude being taken by differential photometry
with respect to the V-band magnitudes of the comparison stars
(designated as "CV" band), so the effective magnitudes are similar to
the V-band but nevertheless different.
On three nights in 2011 February, Myers made long time-series
photometry of T Pyx (CCD images in the "CV" band) with a 0.25m
telescope in Mayhill, New Mexico.
On five nights in 2011 February, Nelson made long time-series
photometry on T Pyx using a 0.32m corrected Dall-Kirkham telescope
at Ellinbank Observatory, in Victoria, Australia.
All our pre-eruption time series are presented in Table 2
(see section 3).
Objects:
------------------------------------------------------
RA (ICRS) DE Designation(s)
------------------------------------------------------
09 04 41.50 -32 22 47.5 V* T Pyx = NOVA Pyx 2011
------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 80 6116 T Pyx in quiescence (1890-2011) and the initial
rise of the 2011 eruption
--------------------------------------------------------------------------------
See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
B/cb : Cataclysmic Binaries, LMXBs, and related objects (Ritter+, 2014)
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
V/123 : Catalog of Cataclysmic Variables (Downes+ 2001-2006)
J/AJ/140/925 : Pre-eruption light curves for Nova U Sco (Schaefer+, 2010)
J/AJ/140/34 : Classification of nova light curves (Strope+, 2010)
J/ApJS/187/275 : Photometric histories of recurrent novae (Schaefer, 2010)
J/other/NewA/13.133 : 2MASS photometry of cataclysmic variables (Ak+, 2008)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d JD Julian Date of observation
15- 20 A6 --- Band Band used in the observation (UBVRI, J, ASAS-V,
CR, CV, Vis.; see the "Description" section
above)
22- 26 F5.2 mag mag [7.1/16] Observed magnitude in Band
28- 31 F4.2 mag e_mag [0.01/0.3] Uncertainty in mag
33- 80 A48 --- r_mag Source of mag
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 19-Feb-2015