A homogeneous catalog of new UBV and H-beta photometry of B- and A-type stars in and around the Scorpius-Centaurus OB association

Slawson, Robert W.; Hill, Robert J.; Landstreet, J. D.

doi:10.1086/191711

Cited by 22 publications

(27 citation statements)

References 1 publication

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“…Our results indicate that this star is deficient in Fe which corroborates the results from Acke & Waelkens (2004). This star is photometrically constant within ∼1% in V, by comparing data in the literature (Hu et al 1989;Slawson et al 1992;Malfait et al 1998;de Winter et al 2001;Vieira et al 2003). We will therefore assume that the photometric variability will not affect our analysis of the RACs optical depth.…”

Section: Hd 100546supporting

confidence: 91%

“…It was classified by Koch et al (1963) as an eclipsing binary of Algol type but following Friedemann et al (1996) and van der Veen et al (1994) its classification as a binary is still uncertain and more observations are required. HD 145718 is photometrically variable, presenting a small magnitude variation (∼1% in V) comparing data in the literature (Wolf & Kern 1983;Slawson et al 1992;Vieira et al 2003). We will therefore assume that the photometric variability will not affect our analysis of the RACs optical depth.…”

Section: Hd 145718supporting

confidence: 68%

“…HD 142666 is photometrically variable comparing data in the literature (Slawson et al 1992;Malfait et al 1998;Oudmaijer et al 2001;Vieira et al 2003). The amplitude of variation can reach up to ∼1.0 in V on a time scale of months (Meeus et al 1998).…”

Section: Hd 142666mentioning

confidence: 89%

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Stellar parameters and evidence of circumstellar activity for a sample of Herbig Ae/Be stars

Guimarães

Alencar²,

Corradi³

et al. 2006

A&A

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Aims. We investigate evidence of accretion in a sample of 15 Herbig Ae/Be stars to determine whether these events originate in a remnant gaseous structure from the primordial cloud (rich in hydrogen) or in a metal-rich body (like comets in our Solar System). During such analysis we also determine precise stellar parameters for this sample of stars. Methods. The stars were observed using high resolution spectroscopy (R = 48 000). A synthetic photospheric spectrum was constructed and then subtracted from the observed one to obtain the circumstellar component. An iterative procedure was applied to find the stellar parameters that were used to build the synthetic photospheric spectrum. Results. Evidence of circumstellar activity were found in four stars: HD 100546, HD 142666, HD 144432 and HD 145718. The presence of redshifted absorption features only in the Balmer lines implies that the accreting material is hydrogen-rich, excluding the possibility that the accretion events might have been created by comet-like bodies. We determined effective temperature, surface gravity, metallicity and the projected rotational velocity for the stars in our sample.

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Section: Hd 100546supporting

confidence: 91%

Section: Hd 145718supporting

confidence: 68%

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Stellar parameters and evidence of circumstellar activity for a sample of Herbig Ae/Be stars

Guimarães

Alencar²,

Corradi³

et al. 2006

A&A

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“…The B − V and U − B colours given above agree with the B8V type reported in the SIMBAD database. Similarly, Slawson's (1992) colours, when dereddened ((B − V) 0 = −0.10, (U − B) 0 = −0.37), are suggestive of a spectral type around B7.5. A primary temperature of ß12 000 K can be posited (Budding & Demircan 2007), although Sokolov (1995) gave a much higher representative temperature for the pair as 16 130 ± 960 K, from analysis of the ultraviolet continuum slope.…”

Section: Photometric Analysismentioning

confidence: 96%

The Multiple Star η Muscae

Budding

Butland

Blackford³

2013

Publ. Astron. Soc. Aust.

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High-resolution spectroscopy of η Mus is combined with literature and new photometry to provide a comprehensive analysis of its components. Our main absolute parameters for the close binary system are M 1 and M 2 3.34 ± 0.04 M ࣻ , R 1 2.13 ± 0.07 R ࣻ , R 2 2.34 ± 0.10 R ࣻ ; T 1 13 000 ± 300, T 2 12 600 ± 300, K; and distance 125 ± 10 pc. Our findings update earlier results in a number of respects. We thus confirm that η Mus B is a gravitationally bound companion of the close binary. This relates to the variable γ velocity of the radial velocities of η Mus A. We connect this to the recently discovered member η Mus D, whose orbit we link to new data. We also provide a spectroscopic examination of the Ap star η Mus B, listing over 450 identified lines. We argue that the system is still young, and the apparently anomalous rotation of the close binary's secondary can be reconciled with its being a physically larger star, still condensing to the zero-age main sequence. Models of young condensing stars permit such expanded states, particularly during the deuterium-burning stage, and our results are in agreement with appropriate low-age models. This possible configuration may make η Mus an important example for testing young star models, formation, and evolution scenarios. This multiple star can be compared with V831 Cen and the general properties related to its membership of the Sco-Cen OB2 association.

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“…Starting from the photometric measurements of Slawson et al (1992, we note that the contribution of HD 131399BC is insignificant in the optical) we furthermore constrained the interstellar reddening E(B − V) and extinction A V (adopting a standard ratio of total-to-selective extinction of 3.1) by comparison with synthetic photometry of the model flux. From these and the known distance, we determined the absolute visual magnitude M V of HD 131399A, and by adopting the bolometric correction from our model atmosphere, the absolute bolometric magnitude M bol (see Table 2).…”

Section: Model Atmosphere Analysismentioning

confidence: 99%

Candidate exoplanet host HD 131399A: a nascent Am star

Przybilla

Aschenbrenner

Buder

2017

A&A

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Direct imaging suggests that there is a Jovian exoplanet around the primary A-star in the triple-star system HD 131399. We investigate a high-quality spectrum of the primary component HD 131399A obtained with FEROS on the ESO/MPG 2.2 m telescope, aiming to characterise the star's atmospheric and fundamental parameters, and to determine elemental abundances at high precision and accuracy. The aim is to constrain the chemical composition of the birth cloud of the system and therefore the bulk composition of the putative planet. A hybrid non-local thermal equilibrium (non-LTE) model atmosphere technique is adopted for the quantitative spectral analysis. Comparison with the most recent stellar evolution models yields the fundamental parameters. The atmospheric and fundamental stellar parameters of HD 131399A are constrained to T eff = 9200 ± 100 K, log g = 4.37 ± 0.10, M = 1.95 +0.08 −0.06 M , R = 1.51 +0.13 −0.10 R , and log L/L = 1.17 ± 0.07, locating the star on the zero-age main sequence. Non-LTE effects on the derived metal abundances are often smaller than 0.1 dex, but can reach up to ∼0.8 dex for individual lines. The observed lighter elements up to calcium are overall consistent with present-day cosmic abundances, with a C/O ratio of 0.45 ± 0.07 by number, while the heavier elements show mild overabundances. We conclude that the birth cloud of the system had a standard chemical composition, but we witness the onset of the Am phenomenon in the slowly rotating star. We furthermore show that non-LTE analyses have the potential to solve the remaining discrepancies between observed abundances and predictions by diffusion models for Am stars. Moreover, the present case allows mass loss, not turbulent mixing, to be identified as the main transport process competing with diffusion in very young Am stars.

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A homogeneous catalog of new UBV and H-beta photometry of B- and A-type stars in and around the Scorpius-Centaurus OB association

Cited by 22 publications

References 1 publication

Stellar parameters and evidence of circumstellar activity for a sample of Herbig Ae/Be stars

Stellar parameters and evidence of circumstellar activity for a sample of Herbig Ae/Be stars

The Multiple Star η Muscae

Candidate exoplanet host HD 131399A: a nascent Am star

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