The X-ray emission from Z Canis Majoris during an FUor-like outburst and the detection of its X-ray jet

Stelzer, B.; Hubrig, S.; Orlando, S.; Micela, G.; Mikulášek, Zdeněk; Schöller, M.

doi:10.1051/0004-6361/200911750

Cited by 31 publications

(32 citation statements)

References 32 publications

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“…There is however no significant change of the Ks-band flux as far as we can tell from the K-band flux ratios given in Table 2 or from comparing the most recent report of infrared observations by Antoniucci et al (2009) of Ks = 3.56 at the peak of the light curve in March 2009, with Ks = 3.79 reported by Koresko et al (1991). Similarly there is no change in the X-ray properties reported by Stelzer et al (2009) with respect to earlier measurement at a "quiescent" phase. If the short-term optical brightening was an EXor-like accretion event, X-ray variability would have been expected.…”

Section: Origin Of the Outburstssupporting

confidence: 56%

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The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris^,

Szeifert

Hubrig

Schöller

et al. 2010

A&A

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Context. Z CMa is a binary system which consists of two young stars: a Herbig AeBe component Z CMa NW embedded in a dust cocoon and a less massive component Z CMa SE, which is classified as a FU Orionis type star. Associated to the binary system is a giant parsec-size jet. Past spectropolarimetric observations showed that the position angle of the linear optical polarization is perpendicular to the jet axis, indicating that the visual light escapes the cocoon via cavities aligned with the jet axis and is then scattered back into the line of sight of the observer. Recently the system showed the largest outburst reported during the almost 90 years of available observations. Aims. We present new spectrophotometric and spectropolarimetric data obtained in 2008 during the recent outburst phase. Methods. The data obtained in the visual spectral range at medium spectral resolution were used to study the geometry of the system from the linear polarization spectra as well as its magnetic field from the circular polarization spectra. Results. During the recent outburst we detected that the Z CMa system is polarized by 2.6% in the continuum and emission line spectrum, with a position angle still perpendicular to the jet. From the high level of polarization we concluded that the outburst is associated with the dust-embedded Herbig AeBe NW component. The deep absorption components of the Balmer lines in the velocity frame which extend from zero velocity and reach a wind velocity of ∼700 km s −1 , together with the absence of a red-shifted broad emission at similar velocities, indicate a bi-polar wind. We did not detect a significant mean longitudinal magnetic field during the outburst, but in the data obtained in 2004 we detected the possible presence of a rather strong magnetic field of the order of ∼1 kG. However, we critically review the applied method of magnetic field measurements in the presence of a strong stellar wind. The main result of our studies is that the bolometric luminosity of Z CMa remained surprisingly constant during the recent outburst. We conclude that either the geometry of the cavity through which the light escapes from the cocoon has opened a new path or that the screen of dust, which reflects the light toward the observer became more efficient, causing the observed increase of the visual brightness by about 2. m 5.

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Section: Origin Of the Outburstssupporting

confidence: 56%

“…This position angle of the polarization indicates that the light from the Z CMa NW component primarily escapes from the envelope by scattering off the walls of a jet-blown cavity. A smaller scale jet with a similar position angle was recently discovered in X-rays by Stelzer et al (2009).…”

Section: Introductionsupporting

confidence: 57%

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris^,

Szeifert

Hubrig

Schöller

et al. 2010

A&A

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“…Variations of the source positions and strength in X-ray images taken a few years apart were observed in a few of these (Favata et al 2006;Stelzer et al 2009 and Fig. 4; Güdel et al 2011).…”

Section: Jets and Outflowsmentioning

confidence: 91%

Variabiity of young stellar objects: Accretion, disks, outflows, and magnetic activity

Stelzer

2015

Astron Nachr

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“…No significant X-ray flux changes were detected also for Z CMa (Stelzer et al 2009), although in this case the optical-infrared brightness increase would be primarily ascribed to variations of the circumstellar dust distribution and not to an accretion outburst (Szeifert et al 2010).…”

Section: Introductionmentioning

confidence: 95%

First X-ray detection of the young variable V1180 Cassiopeiae

Antoniucci

Nucita

Giannini

et al. 2015

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Context. V1180 Cas is a young variable that has shown strong photometric fluctuations (ΔI ∼ 6 mag) in the recent past, which have been attributed to events of enhanced accretion. The source has entered a new high-brightness state in September 2013, which we have previously analysed through optical and near-infrared spectroscopy. Aims. To investigate the current active phase of V1180 Cas, we performed observations with the Chandra satellite aimed at studying the X-ray emission from the object and its connection to accretion episodes. Methods. Chandra observations were performed in early August 2014. Complementary JHK photometry and J-band spectroscopy were taken at our Campo Imperatore facility to relate the X-ray and near-infrared emission from the target. Results. We observe a peak of X-ray emission at the nominal position of V1180 Cas and estimate that the confidence level of the detection is about 3σ. The observed signal corresponds to an X-ray luminosity L X (0.5−7 keV) in the range 0.8 ÷ 2.2 × 10 30 erg s −1 . Based on the relatively short duration of the dim states in the light curve and on stellar luminosity considerations, we explored the possibility that the brightness minima of V1180 Cas are driven by extinction variations. From the analysis of the spectral energy distribution of the high state we infer a stellar luminosity of 0.8−0.9 L and find that the derived L X is comparable to the average X-ray luminosity values observed in T Tauri objects. Moreover, the X-ray luminosity appears to be lower than the X-ray emission levels around 5 × 10 30 ÷ 1 × 10 31 erg s −1 detected at outbursts in similar low-mass objects. Conclusions. Our analysis suggests that at least part of the photometric fluctuations of V1180 Cas might be extinction effects rather than the result of accretion excess emission. However, because the source displays spectral features indicative of active accretion, we speculate that its photometric variations might be the result of a combination of accretion-induced and extinction-driven effects, as suggested for other young variables, such as V1184 Tau and V2492 Cyg.

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The X-ray emission from Z Canis Majoris during an FUor-like outburst and the detection of its X-ray jet

Cited by 31 publications

References 32 publications

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris^,

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris^,

Variabiity of young stellar objects: Accretion, disks, outflows, and magnetic activity

First X-ray detection of the young variable V1180 Cassiopeiae

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The X-ray emission from Z Canis Majoris during an FUor-like outburst and the detection of its X-ray jet

Cited by 31 publications

References 32 publications

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris,

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris,

Variabiity of young stellar objects: Accretion, disks, outflows, and magnetic activity

First X-ray detection of the young variable V1180 Cassiopeiae

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Product

Resources

About

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris^,

The nature of the recent extreme outburst of the Herbig Be/FU Orionis binary Z Canis Majoris^,