The Environment of the Optically Brightest Herbig Ae Star, HD 104237

Grady, C. A.; Woodgate, B. E.; Torres, C. A. O.; Henning, Th.; Apai, Dániel; Rodmann, J.; Wang, Hongchi; Stecklum, B.; Linz, H.; Williger, G. M.; Brown, Alexander; Wilkinson, Erik; Harper, G. M.; Herczeg, Gregory J.; Danks, A. C.; Vieira, G. L.; Malumuth, E. M.; Collins, Nicholas R.; Hill, Robert S.

doi:10.1086/420763

Cited by 80 publications

(137 citation statements)

References 69 publications

(85 reference statements)

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“…Estimated luminosity evolution of the HD 104237 binary using Equation 2. We use values ofṀ taken from Figure 7, scaled down by a factor of 10 3 to match the observed accretion rate of the system (Grady et al 2004). Values for the stellar masses were taken from Garcia et al (2013) and stellar radii from Fumel & Böhm (2012).…”

Section: Numerical Limitations and Omissions From The Modelmentioning

confidence: 99%

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Precession and accretion in circumbinary discs: the case of HD 104237

Dunhill

Cuadra

Dougados

2015

Monthly Notices of the Royal Astronomical Society

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We present the results of smoothed particle hydrodynamics (SPH) simulations of the disc around the young, eccentric stellar binary HD 104237. We find that the binary clears out a large cavity in the disc, driving a significant eccentricity at the cavity edge. This then precesses around the binary at a rate of˙ = 0.48 • T −1 b , which for HD 104237 corresponds to a precession period of 40 years. We find that the accretion pattern into the cavity and onto the binary changes with this precession, resulting in a periodic accretion variability driven purely by the physical parameters of the binary and its orbit. For each star we find that this results in order of magnitude changes in the accretion rate. We also find that the accretion variability allows the primary to accrete gas at a higher rate than the secondary for approximately half of each precession period. Using a large number of 3-body integrations of test particles orbiting different binaries, we find good agreement between the precession rate of a test particle and our SPH disc precession. These rates also agree very well with the precession rates predicted by the analytic theory of Leung & Lee (2013), showing that their prescription can be accurately used to predict long-term accretion variability timescales for eccentric binaries accreting from a disc. We discuss the implications of our result, and suggest that this process provides a viable way of preserving unequal mass ratios in accreting eccentric binaries in both the stellar and supermassive black hole regimes.

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Section: Numerical Limitations and Omissions From The Modelmentioning

confidence: 99%

“…The total stellar mass is 3.6 M and the mass ratio inferred from the spectral type of the primary is q b = 0.64. The system is inclined by i 20 • to the plane of the sky (Grady et al 2004;Böhm et al 2004;Garcia et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Precession and accretion in circumbinary discs: the case of HD 104237

Dunhill

Cuadra

Dougados

2015

Monthly Notices of the Royal Astronomical Society

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“…To characterize the disk properties of these sources, we observed them with the VLT imager and spectrometer for mid-infrared (VISIR) on the night of Notes. Columns 4-6: the photometry comes from Grady et al (2004). Column 7: the photometry comes from Luhman et al (2010).…”

Section: Visir Imagingmentioning

confidence: 99%

“…Column 8: the I-band photometry for member ID#1,6,7,8,9 comes from Feigelson et al (2003), whereas the I-band photometry for member ID#10,11,12 is from the DENIS survey (Epchtein et al 1997). Columns 9-11: the photometry for member ID#3,4,6,7 is from Grady et al (2004). The photometry for other members comes from the 2MASS survey (Skrutskie et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Young stars inϵChamaleontis and their disks: disk evolution in sparse associations

Fang

Boekel

Bouwman

et al. 2012

A&A

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Context. The nearby young stellar association Cha has an estimated age of 3-5 Myr, making it an ideal laboratory to study the disk dissipation process and provide empirical constraints on the timescale of planet formation. Aims. We wish to complement existing optical and near-infrared data of the Cha association, which provide the stellar properties of its members, with mid-infrared data that probe the presence, geometry, and mineralogical composition of protoplanetary disks around individual stars. Methods. We combine the available literature data with our Spitzer/IRS spectroscopy and VLT/VISIR imaging data. We use proper motions to refine the membership of Cha. Masses and ages of individual stars are estimated by fitting model atmospheres to the optical and near-infrared photometry, followed by placement in the Hertzsprung-Russell diagram. The Spitzer/IRS spectra are analyzed using the two-layer temperature distribution spectral decomposition method. Results. Two stars previously identified as members, CXOU J120152.8 and 2MASS J12074597, have proper motions that are very different from those of the other stars. But other observations suggest that the two stars are still young and thus might still be related to Cha. HD 104237C is the lowest mass member of Cha with an estimated mass of ∼13-15 Jupiter masses. The very low mass stars USNO-B120144.7 and 2MASS J12005517 show globally depleted spectral energy distributions, pointing at strong dust settling. 2MASS J12014343 may have a disk with a very specific inclination, where the central star is effectively screened by the cold outer parts of a flared disk, but the 10 μm radiation of the warm inner disk can still reach us. We find that the disks in sparse stellar associations are dissipated more slowly than those in denser (cluster) environments. We detect C 2 H 2 rovibrational band around 13.7 μm on the IRS spectrum of USNO-B120144.7. We find strong signatures of grain growth and crystallization in all Cha members with 10 μm features detected in their IRS spectra. We combine the dust properties derived in the Cha sample with those found using identical or similar methods in the MBM 12, Coronet, η Cha associations, and in the cores-to-disks legacy program. We find that disks around low-mass young stars show a negative radial gradient in the mass-averaged grain size and mass fraction of crystalline silicates. A positive correlation exists between the mass-averaged grain sizes of amorphous silicates and the accretion rates if the latter is above ∼10 −9 M yr −1 , possibly indicating that those disks are sufficiently turbulent to prevent grains of several microns in size to sink into the disk interior.

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“…As a result, dense azimutal structures are formed in the corotating interaction regions (CIRs). The existence of a magnetic collimator is further supported by the detection of low-density Lyα jets in HD 163296 and HD 104237 (Devine et al, 2000;Grady et al, 2004). Magnetic field dissipation also seems the most likely source for the radiative losses in the chromosphere/wind that represent 4-8% of the stellar bolometric luminosity according to Bouret and Catalá (1998), although accretion flows may be a non-negligible energy source (Blondel et al, 1983;Bouret and Catalá, 2000;Roberge et al, 2001).…”

Section: Herbig Ae/be Starsmentioning

confidence: 88%

UV Capabilities to Probe the Formation of Planetary Systems: From the ISM to Planets

Castro

Lecavelier

D’Avillez

et al.

Fundamental Questions in Astrophysics: Guidelines for Future UV Observatories

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Planetary systems are angular momentum reservoirs generated during star formation. Solutions to three of the most important problems in contemporary astrophysics are needed to understand the entire process of planetary system formation:The physics of the ISM. Stars form from dense molecular clouds that contain ∼30% of the total interstellar medium (ISM) mass. The structure, properties and lifetimes of molecular clouds are determined by the overall dynamics and evolution of a very complex system -the ISM. Understanding the physics of the ISM is of prime importance not only for Galactic but also for extragalactic and cosmological studies. Most of the ISM volume (∼65%) is filled with diffuse gas at temperatures between 3000 and 300 000 K, representing about 50% of the ISM mass. ing star formation, the so-called accretion-outflow engine. Elementary physical considerations show that, to be efficient, the acceleration region for the outflows must be located close to the star (within 1 AU) where the gravitational field is strong. According to recent numerical simulations, this is also the region where terrestrial planets could form after 1 Myr. One should keep in mind that today the only evidence for life in the Universe comes from a planet located in this inner disk region (at 1 AU) from its parent star. The temperature of the accretion-outflow engine is between 3000 and 10 7 K. After 1 Myr, during the classical T Tauri stage, extinction is small and the engine becomes naked and can be observed at ultraviolet wavelengths. The physics of planet formation. Observations of volatiles released by dust, planetesimals and comets provide an extremely powerful tool for determining the relative abundances of the vaporizing species and for studying the photochemical and physical processes acting in the inner parts of young planetary systems. This region is illuminated by the strong UV radiation field produced by the star and the accretion-outflow engine. Absorption spectroscopy provides the most sensitive tool for determining the properties of the circumstellar gas as well as the characteristics of the atmospheres of the inner planets transiting the stellar disk. UV radiation also pumps the electronic transitions of the most abundant molecules (H 2 , CO, etc.) that are observed in the UV.Here we argue that access to the UV spectral range is essential for making progress in this field, since the resonance lines of the most abundant atoms and ions at temperatures between 3000 and 300 000 K, together with the electronic transitions of the most abundant molecules (H 2 , CO, OH, CS, Springer 34 Astrophys Space Sci (2006) 303:33-52 S 2 , CO + 2 , C 2 , O 2 , O 3 , etc.) are at UV wavelengths. A powerful UV-optical instrument would provide an efficient mean for measuring the abundance of ozone in the atmosphere of the thousands of transiting planets expected to be detected by the next space missions (GAIA, Corot, Kepler, etc.). Thus, a follow-up UV mission would be optimal for identifying Earth-like candidates.

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The Environment of the Optically Brightest Herbig Ae Star, HD 104237

Cited by 80 publications

References 69 publications

Precession and accretion in circumbinary discs: the case of HD 104237

Precession and accretion in circumbinary discs: the case of HD 104237

Young stars inϵChamaleontis and their disks: disk evolution in sparse associations

UV Capabilities to Probe the Formation of Planetary Systems: From the ISM to Planets

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