Are Proto-Planetary Nebulae Shaped by a Binary? Results of a Long-Term Radial Velocity Study

Hrivnak, Bruce J.; Lu, Wenxian; Bohlender, D.; Morris, S. C.; Woodsworth, A. W.; Scarfe, C. D.

doi:10.1088/0004-637x/734/1/25

Cited by 50 publications

(48 citation statements)

References 52 publications

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“…Moreover, these disc-sources are confirmed to be binaries and show orbital periods between 100 and 2000 days (Van Winckel et al 2009;Gorlova et al 2014). In contrast, for the Galactic shellsources long-term radial velocity monitoring efforts have not yet resulted in any clear detected binary orbit (Hrivnak et al 2011), which either confirms the single-star nature of these objects or introduces a possibility that these systems can have companions on very wide orbits.…”

Section: Introductionmentioning

confidence: 89%

Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

Kamath¹,

Wood²,

Winckel³

2015

Mon. Not. R. Astron. Soc.

125

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We have carried out a search for optically visible post-Asymptotic Giant Branch (post-AGB) stars in the Large Magellanic Cloud (LMC). First, we selected candidates with a mid-IR excess and then obtained their optical spectra. We disentangled contaminants with unique spectra such as M-stars, C-stars, planetary nebulae, quasi-stellar objects and background galaxies. Subsequently, we performed a detailed spectroscopic analysis of the remaining candidates to estimate their stellar parameters such as effective temperature, surface gravity (log g), metallicity ([Fe/H]), reddening and their luminosities. This resulted in a sample of 35 likely post-AGB candidates with late-G to late-A spectral types, low log g, and [Fe/H] < −0.5. Furthermore, our study confirmed the existence of the dusty post-Red Giant Branch (post-RGB) stars, discovered previously in our SMC survey, by revealing 119 such objects in the LMC. These objects have mid-IR excesses and stellar parameters (T eff , log g, [Fe/H]) similar to those of post-AGB stars except that their luminosities (< 2500 L ), and hence masses and radii, are lower. These post-RGB stars are likely to be products of binary interaction on the RGB. The post-AGB and post-RGB objects show SED properties similar to the Galactic post-AGB stars, where some have a surrounding circumstellar shell, while some others have a surrounding stable disc similar to the Galactic post-AGB binaries. This study also resulted in a new sample of 162 young stellar objects, identified based on a robust log g criterion. Other interesting outcomes include objects with an UV continuum and an emission line spectrum; luminous supergiants; hot main-sequence stars; and 15 B[e] star candidates, 12 of which are newly discovered in this study.

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Section: Introductionmentioning

confidence: 89%

Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

Kamath¹,

Wood²,

Winckel³

2015

Mon. Not. R. Astron. Soc.

125

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“…These equatorial structures are likely due to the interaction of the central star with a binary companion. But observation wise, there are yet no strong direct observational evidence for this in the PPN phase (Hrivnak et al 2010). Miszalski et al (2009, 2011) discovered some central binary systems in PNe, but no clear connection between the binaries and morphological class.…”

Section: Introductionmentioning

confidence: 99%

A mid-infrared imaging catalogue of post-asymptotic giant branch stars★

Lagadec

Verhoelst

Mékarnia

et al. 2011

Monthly Notices of the Royal Astronomical Society

101

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Post‐asymptotic giant branch (post‐AGB) stars are key objects for the study of the dramatic morphological changes of low‐ to intermediate‐mass stars on their evolution from the AGB towards the planetary nebula stage. There is growing evidence that binary interaction processes may very well have a determining role in the shaping process of many objects, but so far direct evidence is still weak. We aim at a systematic study of the dust distribution around a large sample of post‐AGB stars as a probe of the symmetry breaking in the nebulae around these systems. We used imaging in the mid‐infrared to study the inner part of these evolved stars to probe direct emission from dusty structures in the core of post‐AGB stars in order to better understand their shaping mechanisms. We imaged a sample of 93 evolved stars and nebulae in the mid‐infrared using VLT spectrometer and imager for the mid‐infrared (VISIR)/VLT, T‐Recs/Gemini‐South and Michelle/Gemini‐North. We found that all the proto‐planetary nebulae we resolved show a clear departure from spherical symmetry. 59 out of the 93 observed targets appear to be non‐resolved. The resolved targets can be divided into two categories. (i) The nebulae with a dense central core, that are either bipolar and multipolar and (ii) the nebulae with no central core, with an elliptical morphology. The dense central torus observed likely hosts binary systems which triggered fast outflows that shaped the nebulae.

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“…Again, velocities were determined by fitting a parabola to the upper half of the profiles. More details of the DAO observations and data calibration with these two systems are given in earlier papers (Hrivnak et al 2011(Hrivnak et al , 2013. The observations reported in this study extend through the end of 2015, or to early 2016 in the case of IRAS 07134+1005.…”

Section: Radial Velocity Observations and Reductionsmentioning

confidence: 63%

“…It seems unlikely that these objects evolve into PNe, but rather evolve into white dwarfs without passing through a PN stage. Hrivnak et al (2011) carried out a study of seven bright PPNe to look for long-term radial velocity variations due to binary companions. The observations were carried out from 1991−1995 and then again from 2007−2010.…”

Section: Introductionmentioning

confidence: 99%

Where are the Binaries? Results of a Long-term Search for Radial Velocity Binaries in Proto-planetary Nebulae

Hrivnak

Steene

Winckel

et al. 2017

ApJ

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We present the results of an expanded, long-term radial velocity search (25 yrs) for evidence of binarity in a sample of seven bright proto-planetary nebulae (PPNe). The goal is to investigate the widely-held view that the bipolar or point-symmetric shapes of planetary nebulae (PNe) and PPNe are due to binary interactions. Observations from three observatories were combined from 2007−2015 to search for variations on the order of a few years and then combined with earlier observations from 1991−1995 to search for variations on the order of decades. All seven show velocity variations due to periodic pulsation in the range of 35−135 days. However, in only one PPN, IRAS 22272+5435, did we find even marginal evidence found for multi-year variations that might be due to a binary companion. This object shows marginally-significant evidence of a twoyear period of low semi-amplitude which could be due to a low-mass companion, and it also displays some evidence of a much longer period of >30 years. The absence of evidence in the other six objects for long-period radial velocity variations due to a binary companion sets significant constraints on the properties of

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Are Proto-Planetary Nebulae Shaped by a Binary? Results of a Long-Term Radial Velocity Study

Cited by 50 publications

References 52 publications

Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

A mid-infrared imaging catalogue of post-asymptotic giant branch stars★

Where are the Binaries? Results of a Long-term Search for Radial Velocity Binaries in Proto-planetary Nebulae

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