Near-infrared variability in the star-forming region RCW 38

Dörr, M.; Chini, R.; Haas, Martín; Lemke, R.; Nürnberger, D. E. A.

doi:10.1051/0004-6361/201220311

Cited by 4 publications

(7 citation statements)

References 24 publications

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“…Fig. 3 in Dörr et al 2013). 3 The assumption that the variations also occur in the CSD implies the existence of a CSD.…”

Section: Discussionmentioning

confidence: 99%

“…The observations, data reduction and PSF photometry have been described and tabulated by Dörr et al (2013). In brief, observations were carried out with the 80 cm IRIS telescope (Hodapp et al 2010) during a monitoring campaign between February and March 2011, with a median daily cadence in the J, H, K s bands (henceforth K s is abbreviated as K).…”

Section: Near-infrared Datamentioning

confidence: 99%

“…Fig. 1 shows the JHK color-color diagram of 122 variable sources with K < 15 mag and having H and K errors smaller than 0.1 mag (Table 1 of Dörr et al 2013). For all but two stars the averaged photometric values are plotted.…”

Section: Near-infrared Datamentioning

confidence: 99%

“…Here, we report on a first feasibility study, with the focus on the linear relationship between the H and K fluxes, and subsequent potential applications. Dörr et al (2013). The main sequence is shown in blue and the locus of unreddened classical T Tauri stars (CTTS) by the red long-dashed line.…”

Section: Introductionmentioning

confidence: 99%

“…Such a large R value does not fit the overall consistency of the RCW 38 sources in the JHK color-color diagram with the standard extinction law (e.g. Fig.3inDörr et al 2013).3 The assumption that the variations occur also in the CSD, implies the existence of a CSD. Hence, in this case the FVG technique reveals the presence of a CSD.…”

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confidence: 99%

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Circumstellar disks revealed byH/Kflux variation gradients

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et al. 2015

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“…Fig. 3 in Dörr et al 2013). 3 The assumption that the variations also occur in the CSD implies the existence of a CSD.…”

Section: Discussionmentioning

confidence: 99%

Section: Near-infrared Datamentioning

confidence: 99%

Section: Near-infrared Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Circumstellar disks revealed byH/Kflux variation gradients

Núñez

Haas

Chini

et al. 2015

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SPHERE dynamical and spectroscopic characterization of HD 142527B

Claudi

Maire

Mesa

et al. 2019

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Aims. HD142527 is one of the most frequently studied Herbig Ae/Be stars with a transitional disk that hosts a large cavity that is up to about 100 au in radius. For this reason, it has been included in the guaranteed time observation (GTO) SpHere INfrared survey for Exoplanets (SHINE) as part of the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) at the Very Large Telescope (VLT) in order to search for low-mass companions that might explain the presence of the gap. SHINE is a large survey within about 600 young nearby stars are observed with SPHERE with the aim to constrain the occurrence and orbital properties of the giant planet population at large (> 5 au) orbital separation around young stars. Methods. We used the IRDIFS observing mode of SPHERE (IRDIS short for infrared dual imaging and spectrograph plus IFS or integral field spectrograph) without any coronagraph in order to search for and characterize companions as close as 30 mas of the star. Furthermore, we present the first observations that ever used the sparse aperture mask (SAM) for SPHERE both in IRDIFS and IRDIFS_EXT modes. All the data were reduced using the dedicated SPHERE pipeline and dedicated algorithms that make use of the principal component analysis (PCA) and reference differential imaging (RDI) techniques. Results. We detect the accreting low-mass companion HD142527B at a separation of 73 mas (11.4 au) from the star. No other companions with mass greater than 10 M J are visible in the field of view of IFS (∼ 100 au centered on the star) or in the IRDIS field of view (∼ 400 au centered on the star). Measurements from IFS, SAM IFS, and IRDIS suggest an M6 spectral type for HD142527B, with an uncertainty of one spectral subtype, compatible with an object of M= 0.11 ± 0.06 M and R= 0.15 ± 0.07 R . The determination of the mass remains a challenge using contemporary evolutionary models, as they do not account for the energy input due to accretion from infalling material. We consider that the spectral type of the secondary may also be earlier than the type we derived from IFS spectra. From dynamical considerations, we further constrain the mass to 0.26 +0.16 −0.14 M , which is consistent with both our spectroscopic analysis and the values reported in the literature. Following previous methods, the lower and upper dynamical mass values correspond to a spectral type between M2.5 and M5.5 for the companion. By fitting the astrometric points, we find the following orbital parameters: a period of P= 35 − 137 yr; an inclination of i = 121 − 130 • , a value of Ω = 124 − 135 • for the longitude of node, and an 68% confidence interval of ∼ 18 − 57 au for the separation at periapsis. Eccentricity and time at periapsis passage exhibit two groups of values: ∼0.2-0.45 and ∼0.45-0.7 for e, and ∼2015-2020 and ∼2020-2022 for T 0 . While these orbital parameters might at first suggest that HD142527B is not the companion responsible for the outer disk truncation, a previous hydrodynamical analysis of this system showed that they are compatible with...

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Extreme infrared variables from UKIDSS – I. A concentration in star-forming regions

Peña¹,

Lucas²,

Froebrich³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present initial results of the first panoramic search for high-amplitude near-infrared variability in the Galactic Plane. We analyse the widely separated two-epoch K-band photometry in the 5th and 7th data releases of the UKIDSS Galactic Plane Survey. We find 45 stars with ∆K > 1 mag, including 2 previously known OH/IR stars and a Nova. Even though the mid-plane is not yet included in the dataset, we find the majority (66%) of our sample to be within known star forming regions (SFRs), with two large concentrations in the Serpens OB2 association (11 stars) and the Cygnus-X complex (12 stars). Sources in SFRs show spectral energy distributions (SEDs) that support classification as Young Stellar Objects (YSOs). This indicates that YSOs dominate the Galactic population of high amplitude infrared variable stars at low luminosities and therefore likely dominate the total high amplitude population. Spectroscopic follow up of the DR5 sample shows at least four stars with clear characteristics of eruptive pre-main-sequence variables, two of which are deeply embedded. Our results support the recent concept of eruptive variability comprising a continuum of outburst events with different timescales and luminosities, but triggered by a similar physical mechanism involving unsteady accretion. Also, we find what appears to be one of the most variable classical Be stars.

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Near-infrared variability in the star-forming region RCW 38

Cited by 4 publications

References 24 publications

Circumstellar disks revealed byH/Kflux variation gradients

Circumstellar disks revealed byH/Kflux variation gradients

SPHERE dynamical and spectroscopic characterization of HD 142527B

Extreme infrared variables from UKIDSS – I. A concentration in star-forming regions

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