Measuring Optical Extinction toward Young Stellar Objects Using Diffuse Interstellar Bands

Carvalho, Adolfo; Hillenbrand, Lynne A.

doi:10.3847/1538-4357/ac9d8e

Cited by 9 publications

(8 citation statements)

References 71 publications

(99 reference statements)

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“…In contrast to our spectral fits, Alcalá et al (2017) measured M0 and an extinction A V = 1.1 mag, estimated using a K7 template. The lower extinction from our work is consistent with the expectation of low extinction from the non-detection of DIBs (see correlations in Carvalho & Hillenbrand 2022) in both in-burst and quiescent spectra. The spectral type is roughly consistent with the effective temperature measurement of 3750 K by Sipos (2009).…”

Section: Properties Of Ex Lupsupporting

confidence: 91%

The Accretion History of EX Lup: A Century of Bursts, Outbursts, and Quiescence

Wang 王,

Herczeg 沈,

Liu 刘

et al. 2023

ApJ

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EX Lup is the archetype for the class of young stars that undergoes repeated accretion outbursts of ∼5 mag at optical wavelengths that last for months. Despite extensive monitoring that dates back 130 yr, the accretion history of EX Lup remains mostly qualitative and has large uncertainties. We assess historical accretion rates of EX Lup by applying correlations between optical brightness and accretion, developed on multi-band magnitude photometry of the ∼2 mag optical burst in 2022. Two distinct classes of bursts occur: major outbursts (ΔV ∼ 5 mag) have year-long durations, are rare, reach accretion rates of M ̇ acc ∼ 10 − 7 M ⊙ yr−1 at peak, and have a total accreted mass of around 0.1 Earth mass. The characteristic bursts (ΔV ∼ 2 mag) have durations of ∼2–3 months, are more common, reach accretion rates of M ̇ acc ∼ 10 − 8 M ⊙ yr−1 at peak, and have a total accreted mass of around 10−3 Earth masses. The distribution of total accreted mass in the full set of bursts is poorly described by a power law, which suggests different driving causes behind the major outburst and characteristic bursts. The total mass accreted during two classes of bursts is around 2 times the masses accreted during quiescence. Our analysis of the light curves reveals a color-dependent time lag in the 2022 post-burst light curve, attributed to the presence of both hot and cool spots on the stellar surface.

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Section: Properties Of Ex Lupsupporting

confidence: 91%

The Accretion History of EX Lup: A Century of Bursts, Outbursts, and Quiescence

Wang 王,

Herczeg 沈,

Liu 刘

et al. 2023

ApJ

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“…The best-fit A V value is in good agreement with the 1.5 mag measured by Connelley & Reipurth (2018), and is somewhat smaller than the 2.4 mag estimated by Carvalho & Hillenbrand (2022). This may indicate that the DIB method overestimates A V values for E(B − V ) > 0.5.…”

Section: Comparison With Previous Resultssupporting

confidence: 73%

Modeling the Multiwavelength Evolution of the V960 Mon System

Carvalho

Hillenbrand

Hambsch

et al. 2023

ApJ

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We study the evolution of the FU Ori object V960 Mon since its outburst, using available multiwavelength photometric time series over 8 yr, complemented by several epochs of moderate-dispersion spectrophotometry. We find that the source fading can be well-described by a decrease in the temperature of the inner disk, which results from a combination of decreasing accretion rate and increasing inner disk radius. We model the system with a disk atmosphere model that produces the observed variations in multiband photometry (this paper) and high-resolution spectral lines (a companion paper).

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“…Consistent with other FU Ori stars displaying a mixed spectrum with both cooler and hotter opacity contributors, there is also strong evidence for low gravity. In the optical, this is indicated by enhanced Ba II 6141 and 6496 Å absorption lines with positive luminosity effect (Andrievsky 1998), as well as the strengths of several Ti I lines and the ratio of Fe II 5316 Å to Fe I 5328 Å that are highlighted by Carvalho et al (2023b) as gravity-sensitive. In the infrared, important indicators of low surface gravity are the Sr II lines in the Y-band (Sharon et al 2010), CN in the J-band (Wallace et 2000), and the strong Si I line in the H-band (Meyer et al 1998).…”

Section: Disk Linesmentioning

confidence: 97%

“…Source extinction can also be probed spectroscopically, given that the optical spectrum of RNO 54 displays clear diffuse interstellar band (DIB) absorption at 5850, 6270, 6379, and 6614 Å. Relations established in Carvalho & Hillenbrand (2022) can be applied to the 6614 Å DIB strength of 332 ± 2 mÅ, to infer a reddening value of E(B − V ) = 1.35 mag and thus a visual extinction estimate of A V = 4.2 mag. We note that this is identical to the Gaia DR3 value quoted above.…”

Section: Basic Spectral Analysismentioning

confidence: 99%

RNO 54: A Previously Unappreciated FU Ori Star

Hillenbrand,

Carvalho,

van Roestel

et al. 2023

ApJL

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We present evidence in support of the hypothesis that the young stellar object RNO 54 is a mature-stage FU Ori type source. The star was first cataloged as a “red nebulous object” in the 1980s but appears to have undergone its outburst prior to the 1890s. Present-day optical and near-infrared spectra are consistent with those of other FU Ori-type stars, both in the details of spectral line presence and shape, and in the overall change in spectral type from an FGK-type in the optical, to the M-type presented in the near-infrared. In addition, the spectral energy distribution of RNO 54 is well-fit by a pure-accretion disk model with parameters: M ̇ = 10 − 3.45 ± 0.06 M ⊙ yr−1, M * = 0.23 ± 0.06 M ⊙, and R inner = 3.68 ± 0.76 R ⊙, though we believe R inner is likely close to its upper range of 4.5R ⊙ in order to produce a T max = 7000 K that is consistent with the optical to near-infrared spectra. The resulting L acc is ∼265 L ⊙. To find these values, we adopted a source distance d = 1400 pc and extinction A V = 3.9 mag, along with disk inclination i = 50 deg based on the consideration of confidence intervals from our initial disk model, and in agreement with observational constraints. The new appreciation of a well-known source as an FU Ori-type object suggests that other such examples may be lurking in extant samples.

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Measuring Optical Extinction toward Young Stellar Objects Using Diffuse Interstellar Bands

Cited by 9 publications

References 71 publications

The Accretion History of EX Lup: A Century of Bursts, Outbursts, and Quiescence

The Accretion History of EX Lup: A Century of Bursts, Outbursts, and Quiescence

Modeling the Multiwavelength Evolution of the V960 Mon System

RNO 54: A Previously Unappreciated FU Ori Star

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