H 187 - At the Onset of a New Eclipse

Barsunova, O. Yu.; Гринин, В. П.; Сергеев, С. Г.

doi:10.1007/s10511-005-0043-2

Cited by 6 publications

(11 citation statements)

References 12 publications

(25 reference statements)

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“…There are also a smaller number of other observations in the UBV R bands. Barsunova et al (2005) have independently monitored KH 15D in the Johnson V and Cousins R and I bands since 2002, using the 0.7 m telescope of the Crimean Astrophysi-cal Observatory. Eighteen of their I band measurements were taken within 6 hours of a measurement by Hamilton et al (2005), which, as in the previous section, gives us an opportunity to check for consistency between the teams' different photometric procedures.…”

Section: Ccd Photometrymentioning

confidence: 99%

“…For our model-fitting purposes, we considered all of the I-band data of Hamilton et al (2005) and Barsunova et al (2005), after transforming the latter data set according to Eq. (2) for the sake of uniformity.…”

Section: Ccd Photometrymentioning

confidence: 99%

“…It has since been confirmed that KH 15D is a spectroscopic binary with an eccentric orbit . In addition, a wealth of new photometric data has become available, from analyses of archival photographs (Johnson et al 2005, Maffei, Ciprini, & Tosti 2005, and modern CCD observations (Hamilton et al 2005; Barsunova, Grinin, & Sergeev 2005;Kusakabe et al 2005). Our main motivation for the work described in this paper was to test whether or not the circumbinary-disk model is consistent with these new data.…”

Section: Introductionmentioning

confidence: 99%

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The Orbit and Occultations of KH 15D

Winn

Hamilton

Herbst

et al. 2006

ApJ

132

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The unusual flux variations of the pre-main-sequence binary star KH 15D have been attributed to occultations by a circumbinary disk. We test whether or not this theory is compatible with newly available data, including recent radial velocity measurements, CCD photometry over the past decade, and photographic photometry over the past 50 years. We find the model to be successful, after two refinements: a more realistic motion of the occulting feature, and a halo around each star that probably represents scattering by the disk. The occulting feature is exceptionally sharp-edged, raising the possibility that the dust in the disk has settled into a thin layer, and providing a tool for fine-scale mapping of the immediate environment of a T Tauri star. However, the window of opportunity is closing, as the currently visible star may be hidden at all orbital phases by as early as 2008.Comment: To appear in ApJ [16 pages, 13 figures

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Section: Ccd Photometrymentioning

confidence: 99%

Section: Ccd Photometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Orbit and Occultations of KH 15D

Winn

Hamilton

Herbst

et al. 2006

ApJ

132

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“…1 Other designations: TJ 108, LDL 35, LRL 35. (Barsunova et al 2005). More detailed observations by Nordhagen et al (2006) show that V718 Per undergoes recurrent, 3.5 year long eclipses with a period of P = 4.7 ± 0.1 years (see also Grinin et al 2006a).…”

Section: Introductionmentioning

confidence: 99%

The unusual pre-main-sequence star V718 Persei (HMW 15)

Гринин¹,

Stempels²,

Gahm³

et al. 2008

A&A

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Context. The remarkable pre-main-sequence object V718 Per (HMW 15, H187) in the young cluster IC 348 periodically undergoes long-lasting eclipses caused by variable amounts of circumstellar dust in the line-of-sight to the star. It has been speculated that the star is a close binary and similar to another unusual eclipsing object, KH 15D. Aims. We have submitted V718 Per to a detailed photometric and spectroscopic study to investigate how regular the recurrent eclipses are, to find out more about the properties of the stellar object and the occulting circumstellar material, and to look for signatures of a possible binary component. Methods. V718 Per was monitored photometrically from the optical to the near-infrared (NIR). We also obtained high-resolution optical spectra with the Keck telescope at minimum as well as at maximum brightness. We derived the fundamental photospheric parameters of this star by comparing with synthetic spectra. Results. Our photometric data show that the eclipses are very symmetric and persistent, and that the extinction law of the foreground occulting dust deviates only little from what is expected for "normal" interstellar material. The stellar parameters of V718 Per indicate a primordial abundance of Li and a surface temperature of T eff ≈ 5200 K. Remarkably, the in-eclipse spectrum shows a significant broadening of the photospheric absorption lines, as well as a slightly lower stellar surface temperature. In addition, weak emission components appear in the absorption lines of Hα and the Ca II IR triplet lines. We did not detect any signs of atomic or molecular features related to the occulting body in the in-eclipse spectrum. We also found no evidence of any radial velocity changes in V718 Per to within about ±80 m s −1 , which for an edge-on system corresponds to a maximum companion mass of ∼6 M Jup . Conclusions. Our observations suggest that V718 Per is a single star, and thus very different from the related binary system KH 15D. We conclude that V718 Per is surrounded by an edge-on circumstellar disk with an irregular mass distribution orbiting at a distance of 3.3 AU from the star, presumably at the inner disk edge. To produce the prolonged eclipses, the occulting feature must extend along more than half of the inner disk edge. The change in stellar surface temperature and the emission line activity observed could be related to spot activity. We ascribe the broadening of photospheric absorption lines during the eclipse to forward scattering of stellar light in the circumstellar dust feature.

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“…An analysis of the archive photographic observational data (Johnson and Winn 2004) showed that the brightness of KH 15D was slowly decreasing during the last 40 years (see also Barsunova et al 2004 on this topic). The duration of eclipses (Herbst et al 2002) and their depth (Johnson and Winn 2004) were also slowly changing.…”

Section: Discussionmentioning

confidence: 99%

Disk wind in young binaries and the origin of the cyclic activity of young stars

2004

Self Cite

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We present results of numerical modeling of the cyclic brightness modulation in the young binary systems with the eccentric orbits and low-mass secondary components. It is suggested that the system components accrete the matter from the remnant of the protostellar cloud and, according to the current models, the low-mass companion is the main accretor. Brightness variations of the primary is due to the periodical extinction variations on the line-of-sight caused by the disk wind of the secondary and a common envelope it produces. A matter distribution in the envelope has been calculated in the ballistic approach.When calculating the optical effects due to the dust component of the disk wind, we adopt the dust to gas mass ratio 1:100 as in the interstellar medium and the optical parameters of the circumstellar dust typical for the young stars. Calculations showed that in the young binaries with the elliptic orbits theoretical light curves demonstrated the more variety of shapes comparing with the case of the circular orbits. In this case parameters of the photometric minima (their depth, duration and the shape of light curves) depend not only on the disk wind parameters and an inclination of the binary orbit to the line-of-sight but also on the longitude of the periastron. A modulation of the scattered radiation of the common envelope with a phase of the orbital period has been investigated in the single scattering approach. It is shown that an amplitude of the modulation is maximal when the system is seen edge-on and has also a non-zero value in the binaries observed pole-on. Possible applications of the theory to the young stellar objects are discussed. In particular, an attention is payed to a resemblance of the light curves in some models with light curves of the objects suspected as candidates to FUORs.

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H 187 - At the Onset of a New Eclipse

Cited by 6 publications

References 12 publications

The Orbit and Occultations of KH 15D

The Orbit and Occultations of KH 15D

The unusual pre-main-sequence star V718 Persei (HMW 15)

Disk wind in young binaries and the origin of the cyclic activity of young stars

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