J/A+A/619/A84 EFOSC photometry of M3-2 (Boffin+, 2018)
When Nature Tries to Trick Us. An eclipsing eccentric close binary superposed
on the central star of the planetary nebula M3-2.
Boffin H.M.J., Jones D., Wesson R., Beletsky Y., Miszalski B., Saviane I.,
Monaco L., Corradi R., Santander Garcia M., Rodriguez-Gil P.
<Astron. Astrophys. 619, A84 (2018)>
=2018A&A...619A..84B 2018A&A...619A..84B (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae ; Binaries, eclipsing ; Photometry
Keywords: methods: observational - binaries: eclipsing - stars: early-type -
planetary nebulae: individual: PN G240.3-07.6 -
stars: AGB and post-AGB
Abstract:
Bipolar planetary nebulae (PNe) are thought to result from binary star
interactions and, indeed, tens of binary central stars of PNe have
been found, in particular using photometric time-series that allow
detecting post-common envelope systems. Using photometry at the NTT in
La Silla we have studied the bright object close to the centre of PN
M3-2 and found it to be an eclipsing binary with an orbital period of
1.88 days. However, the components of the binary appear to be two A or
F stars, of almost equal masses, and are thus too cold to be the
source of ionisation of the nebula. Using deep images of the central
star obtained in good seeing, we confirm a previous result that the
central star is more likely a much fainter star, located 2 arcsec away
from the bright star. The eclipsing binary is thus a chance alignment
on top of the planetary nebula. We also studied the nebular abundance
and confirm it to be a Type I PN.
Description:
Photometry and spectroscopy of the bright star close to the centre of
the PN M3-2, obtained with EFOSC2. In the photometry file, for each
epoch, we provide the difference between the magnitude of the bright
object in M3-2 and a comparison star, the associated error, as well as
the difference between the magnitude of two comparison stars to serve
as a check of the stability and the associated error.
We also provide a file with the detected nebular lines and their
intensities.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
07 14 49.92 -27 50 23.2 PN M3-2 = PN G240.3-07.6
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 50 603 Photometry of the bright star inside M3-2
tablea2.dat 96 34 Line intensities in the nebula of M3-2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d Epoch MJD date
16- 22 F7.4 --- Imag1 Differential I magnitude target - comp1
25- 31 F7.4 --- e_Imag1 Error on Imag1
35- 41 F7.4 --- Imag2 Differential I magnitude comp1 - comp2
44- 50 F7.4 --- e_Imag2 Error on Imag2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 0.1nm lambdaObs Observed wavelength of line
9- 15 F7.2 0.1nm lambdaTrue True wavelength of line
17- 24 F8.3 --- Flux Measured flux (1)
26- 31 F6.3 --- e_Flux rms uncertainty on Flux
33- 40 F8.3 --- Int Intensity of line (1)
42- 47 F6.3 --- E_Int Error on intensity of line (upper value)
48- 53 F6.3 --- e_Int Error on intensity of line (lower value)
55- 67 A13 --- Ident Line identification
68- 70 A3 --- Mul Multiplet of the line
72- 80 A9 --- low Lower term of the multiplet
82- 90 A9 --- high Higher term of the multiplet
92- 93 I2 --- g1 ? Statistical weight of the lower energy
level of the transition
95- 96 I2 --- g2 ? Statistical weight of the upper energy
level of the transition
--------------------------------------------------------------------------------
Note (1): Fluxes and Intensities are both in arbitrary units such that
Hβ=100 (within the error).
--------------------------------------------------------------------------------
Acknowledgements:
Henri M.J. Boffin, hboffin(at)eso.org
(End) Henri M.J. Boffin [ESO], Patricia Vannier [CDS] 02-Aug-2018