Diffuse interstellar bands in the spectra of massive young stellar objects

Oudmaijer, R. D.; Busfield, Graeme; Drew, J. E.

doi:10.1093/mnras/291.4.797

Cited by 18 publications

(20 citation statements)

References 18 publications

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“…These bands are strong in lines of sight through molecular clouds (e.g., Vos et al 2011), and when seen in the spectra of some young stars (e.g., Oudmaijer et al 1997; Figure 10. Left: the V−I vs. V color-magnitude diagram from our multiband monitoring of GI Tau, with observed data from 2015-2016 in gray.…”

Section: The Extinction Curve Of the Dips Of Gi Taumentioning

confidence: 93%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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The variability of young stellar objects is mostly driven by star-disk interactions. In long-term photometric monitoring of the accreting T Tauri star GI Tau, we detect extinction events with typical depths of DṼ 2.5 mag that last for days to months and often appear to occur stochastically. In 2014-2015, extinctions that repeated with a quasi-period of 21 days over several months are the first empirical evidence of slow warps predicted by magnetohydrodynamic simulations to form at a few stellar radii away from the central star. The reddening is consistent with =  R 3.85 0.5 V and, along with an absence of diffuse interstellar bands, indicates that some dust processing has occurred in the disk. The 2015-2016 multiband light curve includes variations in spot coverage, extinction, and accretion, each of which results in different traces in color-magnitude diagrams. This light curve is initially dominated by a month-long extinction event and a return to the unocculted brightness. The subsequent light curve then features spot modulation with a 7.03 day period, punctuated by brief, randomly spaced extinction events. The accretion rate measured from U-band photometry ranges from´-1.3 10 8 to´-1.1 10 10 M e yr −1 (excluding the highest and lowest 5% of high-and low-accretion rate outliers), with an average of4.7 -10 9 M e yr −1 . A total of 50% of the mass is accreted during bursts of >´-12.8 10 9 M e yr -1, which indicates limitations on analyses of disk evolution using single-epoch accretion rates.

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Section: The Extinction Curve Of the Dips Of Gi Taumentioning

confidence: 93%

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Guo

Herczeg

Jose

et al. 2018

ApJ

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“…However, the DIBs can only provide a lower limit to the total reddening. Oudmaijer et al (1997) found for a sample of young objects that the majority of the DIBs correlate with the reddening due to interstellar dust, but they remain insensitive to the dust in circumstellar envelopes and their parental molecular clouds. Eight well-known DIBs are clearly identified in both objects; the measured EW for each line, along with the line strength per unit E(B-V) determined from Jenniskens & Desert (1994), and the resulting E(B-V) are given in Table 1.…”

Section: Interstellar Linesmentioning

confidence: 93%

Spectroscopy and linear spectropolarimetry of the early Herbig Be stars PDS 27 and PDS 37

Ababakr¹,

Fairlamb²,

Oudmaijer³

et al. 2015

Mon. Not. R. Astron. Soc.

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The number of well-studied early-type pre-main-sequence objects is very limited, hampering the study of massive star formation from an observational point of view. Here, we present the results of VLT/FORS2 spectropolarimetric and VLT/X-shooter spectroscopic observations of two recently recognised candidate Herbig Be stars, PDS 27 and PDS 37. Through analysis of spectral lines and photometry, we find that these two objects are hot, 17500 ± 3500 K, have large radii, 17.0 ± 4.0 and 25.8 ± 5.0 R ⊙ , and are very massive, 15.3 (+5.4, -4.4) and 21.1 (+11.0, -5.3) M ⊙ for PDS 27 and PDS 37, respectively. This suggests that these two objects are very young in their evolution and may become O-type stars. Their youth is supported by their high accretion rates of the order of 10 −3 -10 −4.5 M ⊙ /yr. A change in linear polarisation across the absorption component of Hα is detected in both objects. This change indicates that the circumstellar environment close to the star, at scales of several stellar radii, has a flattened structure, which we identify as an inner accretion disc. Strong variability is seen in both objects in many lines as further indication of an active circumstellar environment.

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“…Figure 1 shows the spectral region from 5700 Å to 6000 Å of a high-resolution spectrum obtained on 2000 May 15, where the interstellar absorption components of Na I D1 and D2 are deep and the diffuse interstellar absorption bands (DIB) are seen at 5779, 5797, and 5849 Å (Jenniskens & Désert 1994;Oudmaijer et al 1997). The equivalent widths of the interstellar absorption components of Na I D1 and D2, and the selected DIB are given in Table 2.…”

Section: Interstellar Absorption Lines and Bandsmentioning

confidence: 99%

Spectroscopic observations of the recurrent nova CI Aquilae during the 2000 outburst

Iijima¹

2012

A&A

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High-and low-resolution optical spectra of CI Aql were obtained during the outburst in 2000. Multiple absorption components of H I and Fe II lines were detected at the early decline stage. Their radial velocities were roughly −2500 km s −1 , −2200 km s −1 , −1700 km s −1 , and −1400 km s −1 , among which only the last components were likely still accelerating during the early decline stage. Prominent emission lines of [O III] and [N II] appeared about one month after light maximum. The duration of the nebular stage, however, was only one month and a few weeks. The ejected gas shells seem to have started to shrink about 70 days after light maximum. The amount of interstellar extinction is estimated to be E(B − V) = 0.92 ± 0.15 from the equivalent widths of the diffuse interstellar absorption bands. The helium abundance in the ejecta is estimated to be N(He) = 0.19 ± 0.05 and the mass of the ejecta to be about 2 × 10 −6 M . This object has been classified as a U Sco type recurrent nova, but its spectral evolution during the outburst resembled those of T Pyx type recurrent novae. It is doubtful whether the peak of m V 9 mag on 2000 May 5 was the true light maximum or an earlier brighter peak had been overlooked, because the spectral data suggest that the ejections of gas shells occurred prior to the discovery of the outburst on 2000 April 28.

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Diffuse interstellar bands in the spectra of massive young stellar objects

Cited by 18 publications

References 18 publications

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Star–Disk Interactions in Multiband Photometric Monitoring of the Classical T Tauri Star GI Tau

Spectroscopy and linear spectropolarimetry of the early Herbig Be stars PDS 27 and PDS 37

Spectroscopic observations of the recurrent nova CI Aquilae during the 2000 outburst

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