On the nature of the unique eclipsing system H 187 (HMW 15)

Гринин, В. П.; Barsunova, O. Yu.; Сергеев, С. Г.; Sotnikova, N. Ya.; Demidova, T. V.

doi:10.1134/s1063773706120048

Cited by 8 publications

(8 citation statements)

References 11 publications

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“…We estimate the accuracy of the obtained photometric data to be about 0.03 m in V and R, and 0.02 m in I. The photomeric data extend the series presented earlier by Grinin et al (2006a).…”

Section: Photometrysupporting

confidence: 79%

“…(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). Thus, given the very long eclipse duration and its comparitively short period, this system is one of the most exotic eclipsing systems known.…”

Section: Introductionmentioning

confidence: 95%

“…Since a 4.7 year period suggests orbital motion as the underlying cause, most working hypotheses propose that the eclipses are produced by an extended body, Article published by EDP Sciences like an irregular or warped circumstellar or circumbinary disk seen nearly edge-on (Cohen et al 2004;Nordhagen et al 2006;Grinin et al 2006a). A still unresolved question is whether or not V718 Per is a close binary, similar to KH 15D, where the orbital displacement of the stars would periodically hide one or both components behind a shared circumbinary disk.…”

Section: Introductionmentioning

confidence: 99%

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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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“…We estimate the accuracy of the obtained photometric data to be about 0.03 m in V and R, and 0.02 m in I. The photomeric data extend the series presented earlier by Grinin et al (2006a).…”

Section: Photometrysupporting

confidence: 79%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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

Гринин¹,

Stempels²,

Gahm³

et al. 2008

A&A

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show abstract

“…It shows periodic variability by 0.8 mag in I with a period of 4.7 yr and eclipses that last ≈3/4 of the orbit (Grinin et al 2006(Grinin et al , 2008. For comparison, the eclipses in CHS 7797 last 2/3 of the orbit.…”

Section: Single-object Scenariomentioning

confidence: 99%

“…In the following, on the basis of the observations of V718 Per (Grinin et al 2006(Grinin et al , 2008Herbst et al 2010b), we argue that single periodically variable PMS stars with large variation amplitudes can be explained by strong absorption in their circumstellar discs over large fractions of their orbit.…”

Section: Single-object Scenariomentioning

confidence: 99%

An unusual very low-mass high-amplitude pre-main sequence periodic variable

Rodríguez-Ledesma

Mundt

Ibrahimov

et al. 2012

A&A

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Aims. We have investigated the nature of the variability of CHS 7797, an unusual periodic variable in the Orion Nebula Cluster.Methods. An extensive I-band photometric data set of CHS 7797 was compiled between 2004−2010 using various telescopes. Further optical data have been collected in R and z bands. In addition, simultaneous observations of the ONC region including CHS 7797 were performed in the I, J, K s & IRAC 3.6 and 4.5 μm bands over a time interval of ≈40 d. Results. CHS 7797 shows an unusual large-amplitude variation of ≈1.7 mag in the R, I, and z bands with a period 17.786 ± 0.03 d (FAP = 1 × 10 −15 %). The amplitude of the brightness modulation decreases only slightly at longer wavelengths. The star is faint during ≈2/3 of the period and the shape of the phased light-curves for the seven different observing seasons shows minor changes and small-amplitude variations. Interestingly, there are no significant colour-flux correlations for λ < ∼ 2 μm, while the object becomes redder when fainter at longer wavelengths. CHS 7797 has a spectral type of M 6 and an estimated mass between 0.04−0.1 M . Conclusions. The analysis of the data suggests that the periodic variability of CHS 7797 is most probably caused by an orbital motion. Variability as a result of rotational brightness modulation by a hot spot is excluded by the lack of any colour-brightness correlation in the optical. The latter indicates that CHS 7797 is most probably occulted by circumstellar matter in which grains have grown from typical 0.1 μm to ≈1−2 μm sizes. We discuss two possible scenarios in which CHS 7797 is periodically eclipsed by structures in a disc, namely that CHS 7797 is a single object with a circumstellar disc, or that CHS 7797 is a binary system, similar to KH 15D, in which an inclined circumbinary disc is responsible of the variability. Possible reasons for the typical 0.3 mag variations in I-band at a given phase are discussed.

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Dusty disk wind in young binary systems viewed pole-on

Тамбовцева

2008

Astrophysics

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A model of a young binary system with companions of unequal mass whose orbital plane is inclined at a large angle to the line of sight is examined. The system components are assumed to accrete matter from the remains of the protostellar cloud. It is found that eclipsing of the primary component by the disk wind of the secondary can be observed when the plane of the orbit is inclined at a large angle to the line of sight or even when the binary system is observed pole on.

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On the nature of the unique eclipsing system H 187 (HMW 15)

Cited by 8 publications

References 11 publications

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

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

An unusual very low-mass high-amplitude pre-main sequence periodic variable

Dusty disk wind in young binary systems viewed pole-on

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