The Central Star Candidate of the Planetary Nebula Sh2-71: Photometric and Spectroscopic Variability

T. MoËcnik; M. Lloyd; D. Pollacco; R. A. Street

doi:10.1093/mnras/stv983

The Central Star Candidate of the Planetary Nebula Sh2-71: Photometric and Spectroscopic Variability

T. MoËcnik, M. Lloyd, D. Pollacco, R. A. Street

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Abstract

We present the analysis of several newly obtained and archived photometric and spectroscopic datasets of the intriguing and yet poorly understood 13.5-mag central star candidate of the bipolar planetary nebula Sh2-71. Photometric observations con- firmed the previously determined quasi-sinusoidal lightcurve with a period of 68 days and also indicated periodic sharp brightness dips, possibly eclipses, with a period of 17.2 days. In addition, the comparison between U and V lightcurves revealed that the 68-day brightness variations are accompanied by a variable reddening effect of âˆ†E(U âˆ’ V ) = 0.38. Spectroscopic datasets demonstrated pronounced variations in spectral profiles of Balmer, helium and singly ionised metal lines and indicated that these variations occur on a time-scale of a few days. The most accurate verification to date revealed that spectral variability is not correlated with the 68-day brightness vari- ations. The mean radial velocity of the observed star was measured to be âˆ¼26 km s -1 with an amplitude of Â±40 km s -1 . The spectral type was determined to be B8V through spectral comparison with synthetic and standard spectra. The newly proposed model for the central star candidate is a Be binary with a misaligned precessing disc.

Original language	English
Journal	Royal Astronomical Society. Monthly Notices
DOIs	https://doi.org/10.1093/mnras/stv983
Publication status	Published - 2015

Keywords

planetary nebula: individual: Sh2-71 â stars: variables: general â stars: emission-line, Be â binaries: close

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10.1093/mnras/stv983

POST-PEER-REVIEW-NON-PUBLISHERS.PDFAccepted author manuscript, 2.79 MBLicence: CC BY

Cite this

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title = "The Central Star Candidate of the Planetary Nebula Sh2-71: Photometric and Spectroscopic Variability",

abstract = "We present the analysis of several newly obtained and archived photometric and spectroscopic datasets of the intriguing and yet poorly understood 13.5-mag central star candidate of the bipolar planetary nebula Sh2-71. Photometric observations con- firmed the previously determined quasi-sinusoidal lightcurve with a period of 68 days and also indicated periodic sharp brightness dips, possibly eclipses, with a period of 17.2 days. In addition, the comparison between U and V lightcurves revealed that the 68-day brightness variations are accompanied by a variable reddening effect of {\^a}ˆ†E(U {\^a}ˆ{\textquoteright} V ) = 0.38. Spectroscopic datasets demonstrated pronounced variations in spectral profiles of Balmer, helium and singly ionised metal lines and indicated that these variations occur on a time-scale of a few days. The most accurate verification to date revealed that spectral variability is not correlated with the 68-day brightness vari- ations. The mean radial velocity of the observed star was measured to be {\^a}ˆ¼26 km s -1 with an amplitude of {\^A}±40 km s -1 . The spectral type was determined to be B8V through spectral comparison with synthetic and standard spectra. The newly proposed model for the central star candidate is a Be binary with a misaligned precessing disc.",

keywords = "planetary nebula: individual: Sh2-71 {\^a} stars: variables: general {\^a} stars: emission-line, Be {\^a} binaries: close",

author = "T. Mo{\"E}cnik and M. Lloyd and D. Pollacco and Street, {R. A.}",

note = "ML acknowledges support from STFC grant ST/L000768/1.This paper makes use of observations from the LCOGT network, the Liverpool Tele- scope, the Isaac Newton Telescope, the archived data ob- tained from the Anglo-Australian Telescope Data Archive, and the Isaac Newton Group Archive which is maintained as part of the CASU Astronomical Data Centre at the Insti- tute of Astronomy, Cambridge.",

year = "2015",

doi = "10.1093/mnras/stv983",

language = "English",

journal = "Royal Astronomical Society. Monthly Notices",

issn = "1365-2966",

publisher = "Oxford University Press",

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TY - JOUR

T1 - The Central Star Candidate of the Planetary Nebula Sh2-71: Photometric and Spectroscopic Variability

AU - MoËcnik, T.

AU - Lloyd, M.

AU - Pollacco, D.

AU - Street, R. A.

N1 - ML acknowledges support from STFC grant ST/L000768/1.This paper makes use of observations from the LCOGT network, the Liverpool Tele- scope, the Isaac Newton Telescope, the archived data ob- tained from the Anglo-Australian Telescope Data Archive, and the Isaac Newton Group Archive which is maintained as part of the CASU Astronomical Data Centre at the Insti- tute of Astronomy, Cambridge.

PY - 2015

Y1 - 2015

N2 - We present the analysis of several newly obtained and archived photometric and spectroscopic datasets of the intriguing and yet poorly understood 13.5-mag central star candidate of the bipolar planetary nebula Sh2-71. Photometric observations con- firmed the previously determined quasi-sinusoidal lightcurve with a period of 68 days and also indicated periodic sharp brightness dips, possibly eclipses, with a period of 17.2 days. In addition, the comparison between U and V lightcurves revealed that the 68-day brightness variations are accompanied by a variable reddening effect of âˆ†E(U âˆ’ V ) = 0.38. Spectroscopic datasets demonstrated pronounced variations in spectral profiles of Balmer, helium and singly ionised metal lines and indicated that these variations occur on a time-scale of a few days. The most accurate verification to date revealed that spectral variability is not correlated with the 68-day brightness vari- ations. The mean radial velocity of the observed star was measured to be âˆ¼26 km s -1 with an amplitude of Â±40 km s -1 . The spectral type was determined to be B8V through spectral comparison with synthetic and standard spectra. The newly proposed model for the central star candidate is a Be binary with a misaligned precessing disc.

AB - We present the analysis of several newly obtained and archived photometric and spectroscopic datasets of the intriguing and yet poorly understood 13.5-mag central star candidate of the bipolar planetary nebula Sh2-71. Photometric observations con- firmed the previously determined quasi-sinusoidal lightcurve with a period of 68 days and also indicated periodic sharp brightness dips, possibly eclipses, with a period of 17.2 days. In addition, the comparison between U and V lightcurves revealed that the 68-day brightness variations are accompanied by a variable reddening effect of âˆ†E(U âˆ’ V ) = 0.38. Spectroscopic datasets demonstrated pronounced variations in spectral profiles of Balmer, helium and singly ionised metal lines and indicated that these variations occur on a time-scale of a few days. The most accurate verification to date revealed that spectral variability is not correlated with the 68-day brightness vari- ations. The mean radial velocity of the observed star was measured to be âˆ¼26 km s -1 with an amplitude of Â±40 km s -1 . The spectral type was determined to be B8V through spectral comparison with synthetic and standard spectra. The newly proposed model for the central star candidate is a Be binary with a misaligned precessing disc.

KW - planetary nebula: individual: Sh2-71 â stars: variables: general â stars: emission-line, Be â binaries: close

U2 - 10.1093/mnras/stv983

DO - 10.1093/mnras/stv983

M3 - Article

SN - 1365-2966

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

ER -

The Central Star Candidate of the Planetary Nebula Sh2-71: Photometric and Spectroscopic Variability

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