On the nature of the Herbig Be star V 380 Orionis

Rossi, C.; Errico, L.; Friedjung, M.; Giovannelli, F.; Muratorio, G.; Viotti, R.; Vittone, A. A.

doi:10.1051/aas:1999200

Cited by 15 publications

(14 citation statements)

References 13 publications

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“…The relatively large BL contributions for NX Pup, HK Ori, and V380 Ori are probably favoured by the small inclination angles of their discs. This also explains the presence (Shevchenko 1994;Rossi et al 1999). The origin of these lines is still unknown: they could be formed in the (bipolar) outflow or close to the BL.…”

Section: Multiple Solutionsmentioning

confidence: 90%

“…C.30), in particular the strong emissioncomponents in many Fe ii, Cr ii, and Ti ii lines. Later it has been argued that these lines may be formed in an envelope or in the surface wind around the star (Shevchenko 1994(Shevchenko , 1998Rossi et al 1999 Spectroscopic classifications of this star range from F0 iv (Strand 1958) to F4-F8 iii-v (Johnson 1964, HB88). Low resolution spectra CCD spectra obtained by van den Ancker (1996) in the visual and red show the presence of a weak G-band, a strong O i 7774 Å absorption and the Ca ii (2) red-triplet in absorption, probably filled in by emission, as is present in the Balmer lines.…”

Section: C32 V380 Ori -Bd-06mentioning

confidence: 99%

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Modeling of PMS Ae/Fe stars using UV spectra

Blondel

Djie²

2006

A&A

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Context. Spectral classification of PMS Ae/Fe stars, based on visual observations, may lead to ambiguous conclusions. Aims. We aim to reduce these ambiguities by using UV spectra for the classification of these stars, because the rise of the continuum in the UV is highly sensitive to the stellar spectral type of A/F-type stars. Methods. We analyse the low-resolution UV spectra in terms of a 3-component model, that consists of spectra of a central star, of an optically-thick accretion disc, and of a boundary-layer between the disc and star. The disc-component was calculated as a juxtaposition of Planck spectra, while the 2 other components were simulated by the low-resolution UV spectra of well-classified standard stars (taken from the IUE spectral atlases). The hot boundary-layer shows strong similarities to the spectra of late-B type supergiants (see Appendix A). Results. We modeled the low-resolution UV spectra of 37 PMS Ae/Fe stars. Each spectral match provides 8 model parameters: spectral type and luminosity-class of photosphere and boundary-layer, temperature and width of the boundary-layer, disc-inclination and circumstellar extinction. From the results of these analyses, combined with available theoretical PMS evolutionary tracks, we could estimate their masses and ages and derive their mass-accretion rates. For a number of analysed PMS stars we calculated the corresponding SEDs and compared these with the observed SEDs. Conclusions. All stars (except β Pic) show indications of accretion, that affect the resulting spectral type of the stellar photosphere. Formerly this led to ambiguities in classificaton of PMS stars as the boundary-layer was not taken into consideration. We give evidence for an increase of the mass-accretion rate with stellar mass and for a decreases of this rate with stellar age.

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Section: Multiple Solutionsmentioning

confidence: 90%

Section: C32 V380 Ori -Bd-06mentioning

confidence: 99%

Modeling of PMS Ae/Fe stars using UV spectra

Blondel

Djie²

2006

A&A

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“…In particular, the Fe i, and Fe ii emission lines have been observed in several young eruptive stars during their outburst activity (e.g. V1647 Ori, see, e.g., Fedele et al 2007), or in YSOs showing high mass-accretion rates (e.g., Rossi et al 1999).…”

Section: Optical and Nir Spectramentioning

confidence: 99%

POISSON project

Garatti

Lopez

Antoniucci

et al. 2012

A&A

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Context. Characterising stellar and circumstellar properties of embedded young stellar objects (YSOs) is mandatory for understanding the early stages of the stellar evolution. This task requires the combination of both spectroscopy and photometry, covering the widest possible wavelength range, to disentangle the various protostellar components and activities. Aims. As part of the POISSON project (Protostellar Optical-Infrared Spectral Survey On NTT), we present a multi-wavelength spectroscopic and photometric investigation of embedded YSOs in L 1641, aimed to derive the stellar parameters and evolutionary stages and to infer their accretion properties. Methods. Our multi-wavelength database includes low-resolution optical-IR spectra from the NTT and Spitzer (0.6−40 μm) and photometric data covering a spectral range from 0.4 to 1100 μm, which allow us to construct the YSOs spectral energy distributions (SEDs) and to infer the main stellar parameters (visual extinction, spectral type, accretion, stellar, bolometric luminosity, mass accretion, and ejection rates). Results. The NTT optical-NIR spectra are rich in emission lines, which are mostly associated with YSO accretion, ejection, and chromospheric activities. A few emission lines, prominent ice (H 2 O and CO 2 ), and amorphous silicate absorption features have also been detected in the Spitzer spectra. The SED analysis allows us to group our 27 YSOs into nine Class I, eleven Flat, and seven Class II objects. However, on the basis of the derived stellar properties, only six Class I YSOs have an age of ∼10 5 yr, while the others are older (5 × 10 5 −10 6 yr), and, among the Flat sources, three out of eleven are more evolved objects (5 × 10 6 −10 7 yr), indicating that geometrical effects can significantly modify the SED shapes. Inferred mass accretion rates (Ṁ acc ) show a wide range of values (3.6 × 10 −9 to 1.2 × 10 −5 M yr −1 ), which reflects the age spread observed in our sample well. Average values of mass accretion rates, extinction, and spectral indices decrease with the YSO class. The youngest YSOs have the highestṀ acc , whereas the oldest YSOs do not show any detectable jet activity in either images and spectra. Apart from the outbursting source #25 and, marginally, #20, none of the remaining YSOs is accretion-dominated (L acc > L * ). We also observe a clear correlation among the YSOṀ acc , M * , and age. For YSOs with t > 10 5 yr and 0.4 M ≤ M * ≤ 1.2 M , a relationship betweenṀ acc and t (Ṁ acc ∝ t −1.2 ) has been inferred, consistent with mass accretion evolution in viscous disc models and indicating that the mass accretion decay is slower than previously assumed. Finally, our results suggest that episodic outbursts are required for Class I YSOs to reach typical classical T Tauri stars stellar masses.

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“…V380 Ori is a B9-A0 star of 3.3-3.6 M with smallamplitude variability ( Hillenbrand et al 1992;Böhm & Catala 1995;Rossi et al 1999;Herbst & Shevchenko 1999 ). It has a companion star 0B15 from the primary (Corporon & Lagrange 1999).…”

Section: V380 Orimentioning

confidence: 99%

X‐Ray Study of Herbig Ae/Be Stars

Hamaguchi

Yamauchi

Koyama

2005

ApJ

132

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We present ASCA results of intermediate-mass pre-main-sequence ( PMS) stars, or Herbig Ae/Be (HAeBe) stars. Among the 35 ASCA pointed sources, we detect 11 plausible X-ray counterparts. X-ray luminosities of the detected sources in the 0.5-10 keV band are in the range of log L X $ 30 32 ergs s À1 , which is systematically higher than those of low-mass PMS stars. This fact suggests that the contribution of a possible low-mass companion is not large. Most of the bright sources show significant time variation; in particular, two HAeBe stars-MWC 297 and TY CrA-exhibit flarelike events with long decay timescales (e-folding time $10À60 ks). These flare shapes are similar to those of low-mass PMS stars. The X-ray spectra are successfully reproduced by an absorbed one-or two-temperature thin-thermal plasma model. The temperatures are in the range of kT $ 1 5 keV, significantly higher than those of main-sequence OB stars (kT < 1 keV). These X-ray properties are not explained by wind-driven shocks, but are more likely due to magnetic activity. On the other hand, the plasma temperature rises as absorption column density increases or as HAeBe stars ascend to earlier phases. The X-ray luminosity reduces after stellar age of a few times 10 6 yr. X-ray activity may be related to stellar evolution. The age of the activity decay is apparently near the termination of jet or outflow activity. We thus hypothesize that magnetic activity originates from the interaction of the large-scale magnetic fields coupled to the circumstellar disk. We also discuss differences in X-ray properties between HAeBe stars and main-sequence OB stars.

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On the nature of the Herbig Be star V 380 Orionis

Cited by 15 publications

References 13 publications

Modeling of PMS Ae/Fe stars using UV spectra

Modeling of PMS Ae/Fe stars using UV spectra

POISSON project

X‐Ray Study of Herbig Ae/Be Stars

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