Near- and Mid-Infrared Imaging Study of Young Stellar Objects around LkHα 234

Abstract

We present high-resolution (0. ′′ 2) near-infrared images of the area surrounding the Herbig Be star LkHα 234 taken with the Coronagraphic Imager with Adaptive Optics (CIAO) and the adaptive optics on the Subaru Telescope. The near-infrared (J, H, K, L ′ and M ′ bands) images reveal circumstellar structures around LkHα 234 in detail. Eight young stellar object (YSO) candidates (Object B, C, D, E, F, G, NW1, and NW2) were detected at 2 ′′ -11 ′′ from LkHα 234. Objects B and C are likely variable stars, which is consistent with a young evolutionary status. Three objects (LkHα 234, NW1, and NW2) were identified in the 11.8 µm (SiC) and 17.65 µm images obtained with the Long Wavelength Spectrometer (LWS) on the Keck Telescope. NW1 and NW2 are thought to be embedded young stars. We suggest that NW1 and not LkHα 234 is the source illuminating the reflection nebula west of LkHα 234, although Object G may be another candidate. In our images, these objects are located at the center of the 2 µm polarization, and NW1 resides at the center of a monopolar cavity. The SED of NW1 suggests that it is a YSO with a spectral type of B6-7. Object F and G were discovered by our observations at 1. ′′ 9 and 2. ′′ 3, respectively, from LkHα 234, and their proximity to LkHα 234 suggests that they may be its lower-mass companions.

IGRINS NEAR-IR HIGH-RESOLUTION SPECTROSCOPY OF MULTIPLE JETS AROUND LkHα 234*

“…Population diagrams of H 2 lines imply that the gas is thermalized at a McGroarty et al (2004) suggested a parsec-scale jet over ∼ 22 ′ (∼ 8 pc) as projected on the sky, including HH 815 − 822 and HH 103 A. In Figure 1, we show the source candidates and the axes of outflows on the images taken from Kato et al (2011) and Cabrit et al (1997). Also, Table 3 in Kato et al (2011) established the association of sources and source labels from previous studies, which helps the understanding of this region.…”

“…In Figure 1, we show the source candidates and the axes of outflows on the images taken from Kato et al (2011) and Cabrit et al (1997). Also, Table 3 in Kato et al (2011) established the association of sources and source labels from previous studies, which helps the understanding of this region.…”

SMA observations towards the compact, short-lived bipolar water maser outflow in the LkHα234 region

“…The stellar mass for VLA 2 is even more uncertain since the bolometric luminosity is unknown. Yet, its 11.8 µm flux is ∼2.5 weaker than that of VLA 3 (Kato et al 2011), which suggests that VLA 2 is also an intermediate mass star. In fact, from the observed centimetre continuum emission of VLA 2, Torrelles et al (2014) infer a bolometric luminosity of ∼50 L⊙ for this object which can be provided by a protostar of a few solar masses.…”

“…VLA 3 has a bolometric luminosity of ∼700 L⊙ (Kato et al 2011). If all the luminosity would come from a single main sequence star, then the stellar mass would be ∼6 M⊙.…”

The distance to the young cluster NGC 7129 and its age

“…Most fainter stars of the cluster are also young stellar objects (hereafter YSOs) identified by Magakian et al (2004) using spectral observations and VRI photometry, and by Gutermuth et al (2004Gutermuth et al ( , 2009, Muzerolle et al (2004), Stelzer & Scholz (2009) using 2MASS and Spitzer infrared photometry and Chandra X-ray survey. Kato et al (2011) identified some possible YSOs in the close vicinity of LkHα 234 with high-⋆ E-mail:vytautas.straizys@tfai.vu.lt resolution near IR images. For a few YSOs in the cluster and in the dark cloud LDN 1181 located about 0.5 • north of NGC 7129, masses, spectral types, emission-line intensities, BVRI photometry, spectral energy distributions and physical parameters were obtained by Kun et al (2009).…”