Stars, Interstellar Medium and the Galaxy Commons^™

Disk-Outflow Models As Applied To High Mass Star Forming Regions Through Methanol And Water Maser Observations, Hontas Farmer

Hontas F Farmer

As the recent publication by Breen et al (2013) found Class II methanol masers are exclusively associated with high mass star forming regions. Based on the positions of the Class I and II methanol and H2O masers, UC H II regions and 4.5 μm infrared sources, and the center velocities (vLSR) of the Class I methanol and H2O masers, compared to the vLSR of the Class II methanol masers, we propose three disk-outflow models that may be traced by methanol masers. In all three models, we have located the Class II methanol maser near the protostar, and the Class I …

The Xmm-Newton Epic X-Ray Light Curve Analysis Of Wr 6., Richard Ignace, K. G. Gayley, W.-R. Hamann, D. P. Huenemoerder, L. M. Oskinova, A. M. T. Pollock, M. Mcfall

Richard Ignace

We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 d period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for "event clustering" in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays …

Discovery Of A Massive Young Stellar Object In G10.47+0.27 By Way Of Meta Analysis Of Previously Published Data., Hontas F. Farmer

Hontas F Farmer

We report the finding of a previously unidentified candidate massive young stellar object at the precise coordinates right ascension 18 08 38.2 and declination -19 51 50 in the region G10.47+0.27. This object was found by correlation of previously published data. At these coordinates the following key tracers of massive star formation are in a compact area; 4.5 micrometer infrared, a Class II methanol maser, two ionized hydrogen regions and three water masers. We also present a physical model of the disk and outflow in this region based on the morphology and kinematics of the methanol and water masers. Perhaps …

Insights Into High Mass Star Formation From Methanol Maser Observations., Hontas Freeman Farmer

Hontas F Farmer

We present high angular resolution data on Class I and Class II methanol masers, together with other tracers of star formation like H2O masers, ultracompact (UC) ionized hydrogen (H II) regions, and 4.5 μm infrared sources, taken from the literature. The aim is to study what these data tell us about the process of high mass star formation; in particular, whether disk-outflow systems are compatible with the morphology exhibited by Class I and Class II methanol masers. Stars form in the dense cores inside molecular clouds, and while the process of the formation of stars like our Sun is reasonably …

Faraday Rotation Distributions From Stellar Magnetism In Wind-Blown Bubbles., R. Ignace, N. M. Pingel

Richard Ignace

Faraday rotation is a valuable tool for detecting magnetic fields. Here, the technique is considered in relation to wind-blown bubbles. In the context of spherical winds with azimuthal or split monopole stellar magnetic field geometries, we derive maps of the distribution of position angle (P.A.) rotation of linearly polarized radiation across projected bubbles. We show that the morphology of maps for split monopole fields are distinct from those produced by the toroidal field topology; however, the toroidal case is the one most likely to be detectable because of its slower decline in field strength with distance from the star. We …

A Report On The X-Ray Properties Of The Τ Sco Class Of Stars., R. Ignace, L. M. Oskinova, D. Massa

Richard Ignace

An increasing number of OB stars have been shown to possess magnetic fields. Although the sample remains small, it is surprising that the magnetic and X-ray properties of these stars appear to be far less correlated than expected. This contradicts model predictions, which generally indicate that the X-rays from magnetic stars are harder and more luminous than their non-magnetic counterparts. Instead, the X-ray properties of magnetic OB stars are quite diverse.

τ Sco is one example where the expectations are better met. This bright main-sequence, early B star has been studied extensively in a variety of wavebands. It has a …

Investigating The Spectroscopic, Magnetic And Circumstellar Variability Of The O9 Subgiant Star Hd 57682., J. H. Grunhut, G. A. Wade, J. O. Sundqvist, A. Ud-Doula, C. Neiner, R. Ignace, W. L. F. Marcolino, Th. Rivinius, A. Fullerton, L. Kaper, B. Mauclaire, C. Buil, T. Garrel, J. Ribeiro, S. Ubaud

Richard Ignace

The O9IV star HD 57682, discovered to be magnetic within the context of the Magnetism in Massive Stars (MiMeS) survey in 2009, is one of only eight convincingly detected magnetic O-type stars. Among this select group, it stands out due to its sharp-lined photospheric spectrum. Since its discovery, the MiMeS Collaboration has continued to obtain spectroscopic and magnetic observations in order to refine our knowledge of its magnetic field strength and geometry, rotational period and spectral properties and variability. In this paper we report new Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) spectropolarimetric observations of HD 57682, which …

Discovery Of A Magnetic Field In The Rapidly-Rotating O-Type Secondary Of The Colliding-Wind Binary Hd 47129 (Plaskett’S Star)., J. H. Grunhut, G. A. Wade, M. Leutenegger, V. Petit, G. Rauw, C. Neiner, F. Martins, D. H. Cohen, M. Gagné, R. Ignace, S. Mathis, S. E. De Mink, A. F. J. Moffat, S. Owocki, M. Shultz, J. Sundqvist

Richard Ignace

We report the detection of a strong, organized magnetic field in the secondary component of the massive O8III/I+O7.5V/III double-lined spectroscopic binary system HD 47129 (Plaskett's star) in the context of the Magnetism in Massive Stars survey. Eight independent Stokes V observations were acquired using the Echelle SpectroPolarimetric Device for the Observations of Stars (ESPaDOnS) spectropolarimeter at the Canada–France–Hawaii Telescope and the Narval spectropolarimeter at the Télescope Bernard Lyot. Using least-squares deconvolution we obtain definite detections of signal in Stokes V in three observations. No significant signal is detected in the diagnostic null (N) spectra. The Zeeman signatures are broad and …