Investigation of 131 Herbig Ae/Be Candidate Stars

Vieǐra, S.; Corradi, W. J. B.; Alencar, S. H. P.; Mendes, L. T. S.; Torres, C. A. O.; Quast, G.; Guimarães, M. M.; Silva, L. da

doi:10.1086/379553

Cited by 216 publications

(230 citation statements)

References 51 publications

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“…We therefore focus on a sample of Herbig IMS within this volume, that is, Herbig sources within 200 pc that have spectral type F6 or earlier, M å >1.5 M e , and no known stellar companion within 5″. Table 2 compiles a list of sources from the literature meeting these criteria (Walker & Wolstencroft 1988;Malfait et al 1998;Vieira et al 2003;Erickson et al 2011;Chen et al 2012). Generally, these stars are identified by their association with star-forming regions or a reflection nebula and the presence of hydrogen emission lines (particularly Hα).…”

Section: A Volume-limited Sample Of Herbig Starsmentioning

confidence: 99%

“…There is no parallax measurement for this heavily extinguished source, so we adopt the average distance to Taurus (Vieira et al 2003). We adopted the effective temperature (T∼11,000 K) and luminosity (L å =40 L ☉ ) from Hernández et al (2004), and we found that the star is slightly below the ZAMS (49 L ☉ ).…”

Section: Appendix D Comment On Individual Systemsmentioning

confidence: 99%

“…There is no parallax measurement reported for this source, so we adopt the distance used by Vieira et al (2003) based on its cluster membership (d=175 pc). We find L å =9L ☉ , which falls below the ZAMS (14 L ☉ ) for a star with this effective temperature (8,700 K).…”

Section: Appendix D Comment On Individual Systemsmentioning

confidence: 99%

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Spiral Arms in Disks: Planets or Gravitational Instability?

Dong

Najita

Brittain

2018

ApJ

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Spiral arm structures seen in scattered-light observations of protoplanetary disks can potentially serve as signposts of planetary companions. They can also lend unique insights into disk masses, which are critical in setting the mass budget for planet formation but are difficult to determine directly. A surprisingly high fraction of disks that have been well studied in scattered light have spiral arms of some kind (8/29), as do a high fraction (6/11) of wellstudied Herbig intermediate-mass stars (i.e., Herbig stars >1.5 M e ). Here we explore the origin of spiral arms in Herbig systems by studying their occurrence rates, disk properties, and stellar accretion rates. We find that two-arm spirals are more common in disks surrounding Herbig intermediate-mass stars than are directly imaged giant planet companions to mature A and B stars. If two-arm spirals are produced by such giant planets, this discrepancy suggests that giant planets are much fainter than predicted by hot-start models. In addition, the high stellar accretion rates of Herbig stars, if sustained over a reasonable fraction of their lifetimes, suggest that disk masses are much larger than inferred from their submillimeter continuum emission. As a result, gravitational instability is a possible explanation for multiarm spirals. Future observations can lend insights into the issues raised here.

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Section: A Volume-limited Sample Of Herbig Starsmentioning

confidence: 99%

Section: Appendix D Comment On Individual Systemsmentioning

confidence: 99%

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Spiral Arms in Disks: Planets or Gravitational Instability?

Dong

Najita

Brittain

2018

ApJ

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“…We give a brief summary of these here, while we discuss the correction for telluric absorption lines and go into detail on the measurement of line strengths. The stars were selected from the catalogues of HAeBe stars published by Thé, de Winter & Perez (1994) and Vieira et al (2003). The main criterion to be included the sample was their observability in the southern hemisphere during the (southern) summer semester.…”

Section: Sample Observations Data Reduction and Measurementsmentioning

confidence: 99%

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Fairlamb

Oudmaijer

Mendigutía

et al. 2016

Mon. Not. R. Astron. Soc.

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The Herbig Ae/Be stars (HAeBes) allow an exploration of the properties of PreMain Sequence(PMS) stars above the low-mass range (< 2 M ⊙ ) and those bordering the high-mass range (> 8 M ⊙ ). This paper is the second in a series exploring accretion in 91 HAeBes with Very Large Telescope/X-shooter spectra. Equivalent width measurements are carried out on 32 different lines, spanning the UV to NIR, in order to obtain their line luminosities. The line luminosities were compared to accretion luminosities, which were determined directly from measurements of an UV-excess. When detected, emission lines always demonstrate a correlation with the accretion luminosity, regardless of detection frequency. The average relationship between accretion luminosity and line luminosity is found to be L acc ∝ L line 1.16±0.15 . This is in agreement with the findings in Classical T Tauri stars, although the HAeBe relationship is generally steeper, particularly towards the Herbig Be mass range. Since all observed lines display a correlation with the accretion luminosity, all of them can be used as accretion tracers. This has increased the number of accretion diagnostic lines in HAeBes tenfold. However, questions still remain on the physical origin of each line, which may not be due to accretion.

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“…Apart from the H line, which is almost always in emission, the other emission lines that are often observed in the optical spectra of HAeBe stars are He i (kk5876 and 6678), O i (kk7774 and 8446), and the Ca ii triplet (kk8498, 8542, 8662;Herbig 1960;Cohen & Kuhi 1979;Finkenzeller & Mundt 1984;Hamann & Persson 1992;Böhm & Catala 1995) and forbidden emission lines such as [O i] (kk6300 and 6364;Herbig 1960;Hamann 1994;Böhm & Catala 1994;Böhm & Hirth 1997;Corcoran & Ray 1998;Vieira et al 2003;Acke et al 2005). …”

Section: Introductionmentioning

confidence: 99%

Evolution of Emission‐Line Activity in Intermediate‐Mass Young Stars

Manoj

Bhatt

Maheswar

et al. 2006

ApJ

140

139

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We present optical spectra of 45 intermediate-mass Herbig Ae/ Be stars. Together with the multiepoch spectroscopic and photometric data compiled for a large sample of these stars and ages estimated for individual stars by using preYmain-sequence evolutionary tracks, we have studied the evolution of emission-line activity in them. We find that, on average, the H emission line strength decreases with increasing stellar age in Herbig Ae/ Be stars, indicating that the accretion activity gradually declines during the preYmain-sequence phase. This would hint at a relatively longlived (a few Myr) process being responsible for the cessation of accretion in Herbig Ae/ Be stars. We also find that the accretion activity in these stars drops substantially by $3 Myr. This is comparable to the timescale in which most intermediate-mass stars are thought to lose their inner disks, suggesting that inner disks in intermediate-mass stars are dissipated rapidly after the accretion activity has fallen below a certain level. We further find a relatively tight correlation between strength of the emission line and near-infrared excess due to inner disks in Herbig Ae/ Be stars, indicating that the disks around Herbig Ae/ Be stars cannot be entirely passive. We suggest that this correlation can be understood within the framework of the puffed-up inner rim disk models if the radiation from the accretion shock is also responsible for the disk heating.

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Investigation of 131 Herbig Ae/Be Candidate Stars

Cited by 216 publications

References 51 publications

Spiral Arms in Disks: Planets or Gravitational Instability?

Spiral Arms in Disks: Planets or Gravitational Instability?

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Evolution of Emission‐Line Activity in Intermediate‐Mass Young Stars

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