S and VV Corona Australis: Spectroscopic Variability in Two Young Binary Star Systems

Sullivan, Kendall; Prato, L.; Edwards, Suzan; Avilez, Ian; Schaefer, Gail H.

doi:10.3847/1538-4357/ab3c52

Cited by 14 publications

(14 citation statements)

References 71 publications

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“…Note that the bump at ∼ −65 km/s in the spectrum of V836 Tau is a spurious feature caused by the removal of high-frequency fringing and of a CO 2 telluric line while the emission close to the stellar velocity is real. SCrA is a similar spectral type binary separated by 1.3 (Sullivan et al 2019) and we detect blueshifted [Ne II] emission of similar intensity from the optically brighter A and the fainter B starsee Figure 2. Because stellar properties obtained from the optical spectra are for the A+B component , in the following sections we will use the sum of the [Ne II] emission for this source.…”

Section: [Ne Ii] Fluxes and Upper Limitssupporting

confidence: 58%

“…S CrA and VV CrA are two relatively wide binary systems with companions at 1.3 and 1.9 respectively (Joy 1945;Koresko et al 1997;Prato et al 2003). Given that both systems are variable, Sullivan et al (2019) use their 2015 infrared flux ratios to define the primary and secondary star. With this approach, S CrA A is the NW component while VV CrA A is the southern component.…”

Section: B Notes On Complex Systemsmentioning

confidence: 99%

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The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

Pascucci,

Banzatti,

Gorti

et al. 2020

Preprint

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We analyze high-resolution (∆v ≤ 10 km/s) optical and infrared spectra covering the [O I] 6300 Å and [Ne II] 12.81 µm lines from a sample of 31 disks in different evolutionary stages. Following work at optical wavelengths, we use Gaussian profiles to fit the [Ne II] lines and classify them into HVC (LVC) if the line centroid is more (less) blueshifted than 30 km/s with respect to the stellar radial velocity. Unlike for the [O I] where a HVC is often accompanied by a LVC, all 17 sources with a [Ne II] detection have either a HVC or a LVC. [Ne II] HVCs are preferentially detected toward high accretors ( Ṁacc > 10 −8 M /yr) while LVCs are found in sources with low Ṁacc , low [O I] luminosity, and large infrared spectral index (n 13−31 ). Interestingly, the [Ne II] and [O I] LVC luminosities display an opposite behaviour with n 13−31 : as the inner dust disk depletes (higher n 13−31 ) the [Ne II] luminosity increases while the [O I] weakens. The [Ne II] and [O I] HVC profiles are generally similar with centroids and FWHMs showing the expected behaviour from shocked gas in micro-jets. In contrast, the [Ne II] LVC profiles are typically more blueshifted and narrower than the [O I] profiles. The FWHM and centroid vs. disk inclination suggest that the [Ne II]LVC predominantly traces unbound gas from a slow, wideangle wind that has not lost completely the Keplerian signature from its launching region. We sketch an evolutionary scenario that could explain the combined [O I] and [Ne II] results and includes screening of hard (∼ 1 keV) X-rays in inner, mostly molecular, MHD winds.

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Section: [Ne Ii] Fluxes and Upper Limitssupporting

confidence: 58%

Section: B Notes On Complex Systemsmentioning

confidence: 99%

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

Pascucci,

Banzatti,

Gorti

et al. 2020

Preprint

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“…SCrA and VVCrA are two relatively wide binary systems with companions at 1 3 and 1 9, respectively (Joy 1945;Koresko et al 1997;Prato et al 2003). Given that both systems are variable, Sullivan et al (2019) use their 2015 infrared flux ratios to define the primary and secondary stars. With this approach, SCrA A is the NW component, while VVCrA A is the southern component.…”

Section: Appendix a Reduction Of Unpublished Optical Spectra And [O Imentioning

confidence: 99%

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

Pascucci

Banzatti

Gorti

et al. 2020

ApJ

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We analyze high-resolution (Δv10 km s −1) optical and infrared spectra covering the [O I] λ6300 and [Ne II] 12.81 μm lines from a sample of 31 disks in different evolutionary stages. Following work at optical wavelengths, we use Gaussian profiles to fit the [Ne II] lines and classify them into high-velocity component (HVC) or lowvelocity component (LVC) if the line centroid is more or less blueshifted than 30 km s −1 with respect to the stellar radial velocity, respectively. Unlike for the [O I], where an HVC is often accompanied by an LVC, all 17 sources with an [Ne II] detection have either an HVC or an LVC. [Ne II] HVCs are preferentially detected toward high accretors ( >-M 10 acc 8 M e yr −1), while LVCs are found in sources with low  M acc , low [O I] luminosity, and large infrared spectral index (n 13-31). Interestingly, the [Ne II] and [O I] LVC luminosities display an opposite behavior with n 13-31 : as the inner dust disk depletes (higher n 13-31), the [Ne II] luminosity increases while the [O I] weakens. The [Ne II] and [O I] HVC profiles are generally similar, with centroids and FWHMs showing the expected behavior from shocked gas in microjets. In contrast, the [Ne II] LVC profiles are typically more blueshifted and narrower than the [O I] profiles. The FWHM and centroid versus disk inclination suggest that the [Ne II] LVC predominantly traces unbound gas from a slow, wide-angle wind that has not lost completely the Keplerian signature from its launching region. We sketch an evolutionary scenario that could explain the combined [O I] and [Ne II] results and includes screening of hard (∼1 keV) X-rays in inner, mostly molecular, MHD winds.

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“…Due to the narrow slit (0 2) of CRIRES, the spectra cannot be accurately calibrated to an absolute flux density scale. Consequently, we scale the VV CrA A spectra to Wide-field Infrared Survey Explorer (WISE) photometry (24 W1 measurements of the sum of the two VV CrA components between 2010 April and September, average W1 = 4.38 mag), coupled with a flux density ratio between VV CrA A and B at ¢ L of 1.01 (Sullivan et al 2019), obtained on 2015 July 12. However, it is known that VV CrA is variable in the mid-IR at the ∼30% level on a 10 yr timescale (Kóspál et al 2012).…”

Section: Crires 2-5 μM High-resolution Spectroscopymentioning

confidence: 99%

“…It was with these questions in mind that we added the binary VV CrA to our spectroscopic survey. VV CrA is a ∼2 Myr old (Sullivan et al 2019) 2 1 binary located in the Corona Australis star-forming region, at a distance of 157 pc (GAIA DR3; Gaia Collaboration et al 2016Collaboration et al , 2021. It is associated with a Herbig-Haro object (Wang et al 2004).…”

Section: Introductionmentioning

confidence: 99%

An Unusual Reservoir of Water Emission in the VV CrA A Protoplanetary Disk

Salyk¹,

Pontoppidan²,

Banzatti³

et al. 2022

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We present an analysis of an unusual pattern of water vapor emission from the ∼2 Myr old low-mass binary system VV CrA, as observed in IR spectra obtained with VLT-CRIRES, VLT-VISIR, and Spitzer-IRS. Each component of the binary shows emission from water vapor in both the L (∼3 μm) and N (∼12 μm) bands. The N-band and Spitzer spectra are similar to those previously observed from young stars with disks and are consistent with emission from an extended protoplanetary disk. Conversely, the CRIRES L-band data of VV CrA A show an unusual spectrum, which requires the presence of a water reservoir with high temperature (T ≳ 1500 K), column density (N H2O ∼ 3 × 1020 cm−2), and turbulent broadening (v ∼ 10 km s−1) but very small emitting area (A ≲ 0.005 au2). Similarity to previously observed water emission from V1331 Cyg and SVS 13 suggests that the presence of such a reservoir may be linked to evolutionary state, perhaps related to the presence of high accretion rates or winds. While the inner disk may harbor such a reservoir, simple Keplerian models do not match well with emitting line shapes, and alternative velocity fields must be considered. We also present a new idea, that the unusual emission could arise in a circumplanetary disk, embedded within the larger VV CrA A protoplanetary disk. Additional data are likely required to determine the true physical origin of this unusual spectral pattern.

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S and VV Corona Australis: Spectroscopic Variability in Two Young Binary Star Systems

Cited by 14 publications

References 71 publications

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

The Evolution of Disk Winds from a Combined Study of Optical and Infrared Forbidden Lines

An Unusual Reservoir of Water Emission in the VV CrA A Protoplanetary Disk

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