First firm spectral classification of an early-B pre-main-sequence star: B275 in M 17

Ochsendorf, Bram; Ellerbroek, L. E.; Chini, R.; Hartoog, O. E.; Hoffmeister, V. H.; Waters, L.B.F.M.; Kaper, L.

doi:10.1051/0004-6361/201118089

Cited by 25 publications

(34 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on the above, we classify object 2 as a Herbig Ae star. Its radius is "bloated" with respect to its main sequence size, consistent with what is expected (Palla & Stahler 1993) and observed (Ochsendorf et al 2011) in intermediate-mass PMS stars.…”

Section: Results From Spectroscopysupporting

confidence: 89%

RCW36: characterizing the outcome of massive star formation

Ellerbroek

Bik

Kaper

et al. 2013

A&A

Self Cite

View full text Add to dashboard Cite

Context. Massive stars play a dominant role in the process of clustered star formation, with their feedback into the molecular cloud through ionizing radiation, stellar winds, and outflows. The formation process of massive stars is poorly constrained because of their scarcity, the short formation timescale, and obscuration. By obtaining a census of the newly formed stellar population, the star formation history of the young cluster and the role of the massive stars within it can be unraveled. Aims. We aim to reconstruct the formation history of the young stellar population of the massive star-forming region RCW 36. We study several dozen individual objects, both photometrically and spectroscopically, looking for signs of multiple generations of young stars and investigating the role of the massive stars in this process. Methods. We obtain a census of the physical parameters and evolutionary status of the young stellar population. Using a combination of near-infrared photometry and spectroscopy we estimate the ages and masses of individual objects. We identify the population of embedded young stellar objects (YSOs) by their infrared colors and emission line spectra. Results. RCW 36 harbors a stellar population of massive and intermediate-mass stars located around the center of the cluster. Class 0/I and II sources are found throughout the cluster. The central population has a median age of 1.1 ± 0.6 Myr. Of the stars that could be classified, the most massive ones are situated in the center of the cluster. The central cluster is surrounded by filamentary cloud structures; within these, some embedded and accreting YSOs are found. Conclusions. Our age determination is consistent with the filamentary structures having been shaped by the ionizing radiation and stellar winds of the central massive stars. The formation of a new generation of stars is ongoing, as demonstrated by the presence of embedded protostellar clumps and two exposed protostellar jets.

show abstract

Section: Results From Spectroscopysupporting

confidence: 89%

RCW36: characterizing the outcome of massive star formation

Ellerbroek

Bik

Kaper

et al. 2013

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…We check this estimate for consistency by comparing the X-Shooter spectra to model spectra of these subtypes. We adopt a similar by-eye fitting method to the one described in Ochsendorf et al (2011), which is to qualitatively compare the observed profiles of selected lines to model spectra of B-type stars, varying over a range in temperature and surface gravity.…”

Section: Spectroscopymentioning

confidence: 99%

A resolved, au-scale gas disk around the B[e] star HD 50138

Ellerbroek

Benisty

Kraus

et al. 2014

A&A

Self Cite

View full text Add to dashboard Cite

HD 50138 is a B[e] star surrounded by a large amount of circumstellar gas and dust. Its spectrum shows characteristics which may indicate either a pre-or a post-main-sequence system. Mapping the kinematics of the gas in the inner few au of the system contributes to a better understanding of its physical nature. We present the first high spatial and spectral resolution interferometric observations of the Brγ line of HD 50138, obtained with VLTI/AMBER. The line emission originates in a region more compact (up to 3 au) than the continuum-emitting region. Blue-and red-shifted emission originates from the two different hemispheres of an elongated structure perpendicular to the polarization angle. The velocity of the emitting medium decreases radially. An overall offset along the NW direction between the line-and continuum-emitting regions is observed. We compare the data with a geometric model of a thin Keplerian disk and a spherical halo on top of a Gaussian continuum. Most of the data are well reproduced by this model, except for the variability, the global offset and the visibility at the systemic velocity. The evolutionary state of the system is discussed; most diagnostics are ambiguous and may point either to a post-main-sequence or a pre-main-sequence nature.

show abstract

“…the catalogue by The et al (1994)] contains many A-type and late B-type objects, but there is a dearth of the earliest type, most massive Herbig Be (HBe) stars (also see e.g. Ochsendorf et al (2011)). In this paper we present an in-depth investigation of two early HBe star candidates identified by the Pico dos Dias Survey (PDS).…”

Section: Introductionmentioning

confidence: 99%

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.

View full text Add to dashboard Cite

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.

show abstract

First firm spectral classification of an early-B pre-main-sequence star: B275 in M 17

Cited by 25 publications

References 32 publications

RCW36: characterizing the outcome of massive star formation

RCW36: characterizing the outcome of massive star formation

A resolved, au-scale gas disk around the B[e] star HD 50138

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

Contact Info

Product

Resources

About