Spectroscopic behaviour of the unusual Ae star HD 190073

Погодин, М. А.; Franco, G. A. P.; Lopes, D. F.

doi:10.1051/0004-6361:20034290

Cited by 20 publications

(29 citation statements)

References 30 publications

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“…This observing strategy allows us to assess variability on a daily, monthly and yearly basis. The spectroscopic behaviour of HD 190073 was thoroughly studied by Pogodin et al (2005), and we basically confirm their findings with our new observations.…”

Section: Fundamental Parameters Of Hd 190073supporting

confidence: 86%

“…While the existence of a stellar wind is clearly demonstrated by the P Cygni profile at Hα, other processes, such as emission from hot regions above the photosphere can contribute to this emission (see below), so that our estimate ofṀ should be considered as an upper limit. Quite in contrast with the Hα line, the Ca II K & H lines in our spectra do not show conspicuous variability in our one year timeframe, and are even very similar to the profiles presented by Pogodin et al (2005), observed from 1994 to 2000.…”

Section: Unpolarized Spectrumsupporting

confidence: 85%

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The magnetic field of the pre-main sequence Herbig Ae star HD 190073

Catala¹,

Alécian²,

Donati

et al. 2006

A&A

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Context. The general context of this paper is the study of magnetic fields in the pre-main sequence intermediate mass Herbig Ae/Be stars. Magnetic fields are likely to play an important role in pre-main sequence evolution at these masses, in particular in controlling the gains and losses of stellar angular momentum. Aims. The particular aim of this paper is to announce the detection of a structured magnetic field in the Herbig Ae star HD 190073, and to discuss various scenarii for the geometry of the star, its environment and its magnetic field. Methods. We have used the ESPaDOnS spectropolarimeter at CFHT in 2005 and 2006 to obtain high-resolution, high signal-to-noise circular polarization spectra which demonstrate unambiguously the presence of a magnetic field in the photosphere of this star. Results. Nine circular polarization spectra were obtained, each one showing a clear Zeeman signature. This signature is suggestive of a magnetic field structured on large scales. The signature, which corresponds to a longitudinal magnetic field of 74 ± 10 G, does not vary detectably on a one-year timeframe, indicating either an azimuthally symmetric field, a zero inclination angle between the rotation axis and the line of sight, or a very long rotation period. The optical spectrum of HD 190073 exhibits a large number of emission lines. We discuss the formation of these emission lines in the framework of a model involving a turbulent heated region at the base of the stellar wind, possibly powered by magnetic accretion. Conclusions. This magnetic detection contributes an important new observational discovery which will aid our understanding of stellar magnetism at intermediate masses.

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Section: Fundamental Parameters Of Hd 190073supporting

confidence: 86%

Section: Unpolarized Spectrumsupporting

confidence: 85%

The magnetic field of the pre-main sequence Herbig Ae star HD 190073

Catala¹,

Alécian²,

Donati

et al. 2006

A&A

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show abstract

“…Considering its large distance, for which only a lower limit is known due to an imprecise Hipparcos parallax (van den Ancker et al 1998), this unusual object must be far more luminous than other Herbig stars of similar spectral type. The optical spectrum is also quite peculiar (Pogodin et al 2005). The SED shows an IR excess that begins in the NIR and rises to the far-IR.…”

Section: Discussionmentioning

confidence: 99%

Mid-IR observations of circumstellar disks

Schuetz¹,

Meeus

Sterzik³

et al. 2009

A&A

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We present new mid-infrared spectra of 15 targets (1 FU Orionis object, 4 Herbig Ae stars, 5 T Tauri stars, and 5 Vega-type stars), obtained with the TIMMI2 camera at La Silla Observatory (ESO). Three targets are members of the β Pic moving group (HD 155 555, HD 181 296, and HD 319 139). PAH bands are observed towards the T Tauri star HD 34 700 and the Herbig Ae star PDS 144 N. For HD 34 700, the band profiles indicate processed PAHs. The spectrum of the Vega-type object η Corvi (HD 109 085), for which a resolved disk at sub-mm wavelengths is known, appears stellar between 8-13 μm, but a small excess emission was reported by Spitzer observations. Similarly, no indication of circumstellar matter at mid-infrared wavelengths is found towards the Vega-like stars HD 3003, HD 80 951, HD 181 296, and, surprisingly, the T Tauri system HD 155 555. The silicate emission features of the remaining eight sources are modelled with a mixture of silicates of different grain sizes and composition. Unprocessed dust dominates FU Ori, HD 143 006, and CD-43 344. Large amorphous grains are the main dust component around HD 190 073, HD 319 139, KK Oph, and PDS 144 S. Both small grains and crystalline dust is found for the Vega-type HD 123 356, with a dominance of small amorphous grains. We show that the infrared emission of the binary HD 123 356 is dominated by its late-type secondary, but optical spectroscopy is still required to confirm the age of the system and the spectral class of the companion. For most targets, this is their first mid-infrared spectroscopic observation. We investigate trends between stellar, disk, and silicate properties and confirm correlations identified in previous studies. Several objects present an exciting potential for follow-up high-resolution disk studies.

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“…Radii marked as this study were calculated using T eff and bolometric luminosity, both taken from the literature. References: a Doering et al (2007), b Doucet et al (2007), c Ardila et al (2007), d Augereau et al (2001) Vieira et al (2003), z Mora et al (2001), aa Bernacca & Perinotto (1970), bb Pogodin et al (2005), cc de la Reza & Pinzón (2004), dd Blondel & Tjin (2006), ee Hillenbrand et al (1992), f f Wade et al (2007), gg this study (see table caption), hh Tatulli et al (2008), ii Hughes et al (2008), and j j di Folco et al (2004). Comments on the inclination angles deduced in this study, mainly from IUE (LWR and LWP cameras) through analysis of line profile types.…”

Section: Hot Disk Gasmentioning

confidence: 99%

Searching for a link between the magnetic nature and other observed properties of Herbig Ae/Be stars and stars with debris disks

Hubrig

Stelzer

Schöller

et al. 2009

A&A

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100

149

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Context. Recently, evidence for the presence of weak magnetic fields in Herbig Ae/Be stars has been found in several studies. Aims. We seek to expand the sample of intermediate-mass pre-main sequence stars with circular polarization data to measure their magnetic fields, and to determine whether magnetic field properties in these stars are correlated with mass-accretion rate, disk inclination, companions, silicates, PAHs, or show a correlation with age and X-ray emission as expected for the decay of a remnant dynamo. Methods. Spectropolarimetric observations of 21 Herbig Ae/Be stars and six debris disk stars have been obtained at the European Southern Observatory with FORS 1 mounted on the 8 m Kueyen telescope of the VLT. With the GRISM 600B in the wavelength range 3250-6215 Å we were able to cover all hydrogen Balmer lines from Hβ to the Balmer jump. In all observations a slit width of 0. 4 was used to obtain a spectral resolving power of R ≈ 2000. Results. Among the 21 Herbig Ae/Be stars studied, new detections of a magnetic field were achieved in six stars. For three Herbig Ae/Be stars, we confirm previous magnetic field detections. The largest longitudinal magnetic field, B z = −454 ± 42 G, was detected in the Herbig Ae/Be star HD 101412 using hydrogen lines. No field detection at a significance level of 3σ was achieved in stars with debris disks. Our study does not indicate any correlation of the strength of the longitudinal magnetic field with disk orientation, disk geometry, or the presence of a companion. We also do not see any simple dependence on the mass-accretion rate. However, it is likely that the range of observed field values qualitatively supports the expectations from magnetospheric accretion models giving support for dipole-like field geometries. Both the magnetic field strength and the X-ray emission show hints of a decline with age in the range of ∼2-14 Myr probed by our sample, supporting a dynamo mechanism that decays with age. However, our study of rotation does not show any obvious trend of the strength of the longitudinal magnetic field with rotation period. Furthermore, the stars seem to obey the universal power-law relation between magnetic flux and X-ray luminosity established for the Sun and main-sequence active dwarf stars.

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Spectroscopic behaviour of the unusual Ae star HD 190073

Cited by 20 publications

References 30 publications

The magnetic field of the pre-main sequence Herbig Ae star HD 190073

The magnetic field of the pre-main sequence Herbig Ae star HD 190073

Mid-IR observations of circumstellar disks

Searching for a link between the magnetic nature and other observed properties of Herbig Ae/Be stars and stars with debris disks

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