The light curve of the semiregular variable L2 Puppis -- II. Evidence for solar-like excitation of the oscillations

Bedding, Timothy R.; Kiss, L. L.; Kjeldsen, H.; Brewer, Brendon J.; Dind, Z. E.; Kawaler, S. D.; Zijlstra, A. A.

doi:10.1111/j.1365-2966.2005.09281.x

Cited by 43 publications

(49 citation statements)

References 48 publications

(64 reference statements)

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“…The luminosity, effective temperature, and mass we derive for L 2 Pup are consistent with those inferred by Winters et al (2002). Bedding et al (2005) observed that L 2 Pup's period shows smallscale random fluctuations of the phase and amplitude of its photometric variations. Together with the fact that the brightness of L 2 Pup in the K band is very close to the predicted periodluminosity of Mira stars (Bedding et al 2002), this behavior is consistent with a star entering the Mira phase, but with a not yet stabilized pulsation period.…”

Section: Evolutionary Status Of L 2 Pupsupporting

confidence: 88%

An edge-on translucent dust disk around the nearest AGB star, L₂Puppis

Kervella

Montargès

Ridgway

et al. 2014

A&A

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As the nearest known AGB star (d = 64 pc) and one of the brightest (m K ≈ −2), L 2 Pup is a particularly interesting benchmark object to monitor the final stages of stellar evolution. We report new serendipitous imaging observations of this star with the VLT/NACO adaptive optics system in twelve narrow-band filters covering the 1.0−4.0 µm wavelength range. These diffraction-limited images reveal an extended circumstellar dust lane in front of the star that exhibits a high opacity in the J band and becomes translucent in the H and K bands. In the L band, extended thermal emission from the dust is detected. We reproduced these observations using Monte Carlo radiative transfer modeling of a dust disk with the RADMC-3D code. We also present new interferometric observations with the VLTI/VINCI and MIDI instruments. We measured in the K band an upper limit to the limb-darkened angular diameter of θ LD = 17.9 ± 1.6 mas, converting to a maximum linear radius of R = 123 ± 14 R . Considering the geometry of the extended K band emission in the NACO images, this upper limit is probably close to the actual angular diameter of the star. The position of L 2 Pup in the Hertzsprung-Russell diagram indicates that this star has a mass of about 2 M and is probably experiencing an early stage of the asymptotic giant branch. We did not detect any stellar companion of L 2 Pup in our adaptive optics and interferometric observations, and we attribute its apparent astrometric wobble in the H data to variable lighting effects on its circumstellar material. However, we do not exclude the presence of a binary companion, because the large loop structure extending to more than 10 AU to the northeast of the disk in our L-band images may be the result of interaction between the stellar wind of L 2 Pup and a hidden secondary object. The geometric configuration that we propose, with a large dust disk seen almost edge-on, appears particularly favorable to test and develop our understanding of the formation of bipolar nebulae.

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Section: Evolutionary Status Of L 2 Pupsupporting

confidence: 88%

An edge-on translucent dust disk around the nearest AGB star, L₂Puppis

Kervella

Montargès

Ridgway

et al. 2014

A&A

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“…A similar conclusion was reached by Bedding et al (2005) for the star L 2 Puppis. Further work by DS10 and T13 has shown that PL relations are drawn by stochastically excited oscillations.…”

Section: Stochastic Oscillations Versus Mira Variabilitysupporting

confidence: 81%

Period-luminosity relations in evolved red giants explained by solar-like oscillations

Mosser

Dziembowski

Belkacem

et al. 2013

A&A

114

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Context. Solar-like oscillations in red giants have been investigated with the space-borne missions CoRoT and Kepler, while pulsations in more evolved M giants have been studied with ground-based microlensing surveys. After 3.1 years of observation with Kepler, it is now possible to link these different observations of semi-regular variables. Aims. We aim to identify period-luminosity sequences in evolved red giants identified as semi-regular variables and to interpret them in terms of solar-like oscillations. Then, we investigate the consequences of the comparison of ground-based and space-borne observations. Methods. We first measured global oscillation parameters of evolved red giants observed with Kepler with the envelope autocorrelation function method. We then used an extended form of the universal red giant oscillation pattern, extrapolated to very low frequency, to fully identify their oscillations. The comparison with ground-based results was then used to express the period-luminosity relation as a relation between the large frequency separation and the stellar luminosity. Results. From the link between red giant oscillations observed by Kepler and period-luminosity sequences, we have identified these relations in evolved red giants as radial and non-radial solar-like oscillations. We were able to expand scaling relations at very low frequency (periods as long as 100 days and large frequency separation less than 0.05 μHz). This helped us identify the different sequences of period-luminosity relations, and allowed us to propose a calibration of the K magnitude with the observed large frequency separation. Conclusions. Interpreting period-luminosity relations in red giants in terms of solar-like oscillations allows us to investigate the time series obtained from ground-based microlensing surveys with a firm physical basis. This can be done with an analytical expression that describes the low-frequency oscillation spectra. The different behavior of oscillations at low frequency, with frequency separations scaling only approximately with the square root of the mean stellar density, can be used to precisely address the physics of the semi-regular variables. This will allow improved distance measurements and opens the way to extragalactic asteroseismology with the observations of M giants in the Magellanic Clouds.

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“…L 2 Pup is a semi-regular pulsating variable (P ≈ 140 days, Kholopov et al 1985;Bedding et al 2005). An asymmetric resolved environment around L 2 Pup was first identified by Ireland et al (2004) using aperture masking in the optical and near-infrared.…”

Section: Introductionmentioning

confidence: 99%

ALMA observations of the nearby AGB star L₂ Puppis

Kervella

Homan

Richards

et al. 2016

A&A

133

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Six billion years from now, while evolving on the asymptotic giant branch (AGB), the Sun will metamorphose from a red giant into a beautiful planetary nebula. This spectacular evolution will impact the solar system planets, but observational confirmations of the predictions of evolution models are still elusive as no planet orbiting an AGB star has yet been discovered. The nearby AGB red giant L 2 Puppis (d = 64 pc) is surrounded by an almost edge-on circumstellar dust disk. We report new observations with ALMA at very high angular resolution (18 × 15 mas) in band 7 (ν ≈ 350 GHz) that allow us to resolve the velocity profile of the molecular disk. We establish that the gas velocity profile is Keplerian within the central cavity of the dust disk, allowing us to derive the mass of the central star L 2 Pup A, m A = 0.659 ± 0.011 ± 0.041 M (±6.6%). From evolutionary models, we determine that L 2 Pup A had a near-solar main-sequence mass, and is therefore a close analog of the future Sun in 5 to 6 Gyr. The continuum map reveals a secondary source (B) at a radius of 2 AU contributing f B / f A = 1.3 ± 0.1% of the flux of the AGB star. L 2 Pup B is also detected in CO emission lines at a radial velocity of v B = 12.2 ± 1.0 km s −1 . The close coincidence of the center of rotation of the gaseous disk with the position of the continuum emission from the AGB star allows us to constrain the mass of the companion to m B = 12 ± 16 M Jup . L 2 Pup B is most likely a planet or low-mass brown dwarf with an orbital period of about five years. Its continuum brightness and molecular emission suggest that it may be surrounded by an extended molecular atmosphere or an accretion disk. L 2 Pup therefore emerges as a promising vantage point on the distant future of our solar system.

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The light curve of the semiregular variable L2 Puppis -- II. Evidence for solar-like excitation of the oscillations

Cited by 43 publications

References 48 publications

An edge-on translucent dust disk around the nearest AGB star, L₂Puppis

An edge-on translucent dust disk around the nearest AGB star, L₂Puppis

Period-luminosity relations in evolved red giants explained by solar-like oscillations

ALMA observations of the nearby AGB star L₂ Puppis

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The light curve of the semiregular variable L2 Puppis -- II. Evidence for solar-like excitation of the oscillations

Cited by 43 publications

References 48 publications

An edge-on translucent dust disk around the nearest AGB star, L2Puppis

An edge-on translucent dust disk around the nearest AGB star, L2Puppis

Period-luminosity relations in evolved red giants explained by solar-like oscillations

ALMA observations of the nearby AGB star L2 Puppis

Contact Info

Product

Resources

About

An edge-on translucent dust disk around the nearest AGB star, L₂Puppis

An edge-on translucent dust disk around the nearest AGB star, L₂Puppis

ALMA observations of the nearby AGB star L₂ Puppis