We investigate the environment of the nearest Herbig Ae star, HD 104237, with a multiwavelength combination of optical coronagraphic, near-IR, and mid-IR imaging supported by optical, UV, and far-ultraviolet spectroscopy. We confirm the presence of T Tauri stars associated with the Herbig Ae star HD 104237, noted by Feigelson et al. We find that two of the stars within 15 00 of HD 104237 have IR excesses, potentially indicating the presence of circumstellar disks, in addition to the Herbig Ae star itself. We derive a new spectral type of A7.5Ve-A8Ve for HD 104237 and find log (L=L ) ¼ 1:39. With these data, HD 104237 has an age of t % 5 Myr, in agreement with the estimates for the other members of the association. HD 104237 is still actively accreting, with a conspicuous UV/far-UV excess seen down to 1040 8, and is driving a bipolar microjet termed HH 669. This makes it the second, older Herbig Ae star now known to have a microjet. The presence of the microjet enables us to constrain the circumstellar disk to r 0B6 (70 AU) with an inclination angle of i ¼ 18 þ14 À11 from pole-on. The absence of a spatially extended continuum and fluorescent H 2 emission near Ly is in agreement with the prediction of shadowed disk models for the IR spectral energy distribution. With the high spatial density of disks in this group of stars, proximity, and minimal reddening, HD 104237 and its companions should serve as ideal laboratories for probing the comparative evolution of planetary systems.
The Milky Way Imaging Scroll Painting (MWISP) project is an unbiased Galactic plane CO survey for mapping regions of l = −10 • to +250 • and |b| < ∼ 5. • 2 with the 13.7 m telescope of the Purple Mountain Observatory. The legacy survey aims to observe the 12 CO, 13 CO, and C 18 O (J=1-0) lines simultaneously with full-sampling using the nine-beam Superconducting SpectroScopic Array Receiver (SSAR) system with an instantaneous bandwidth of 1 GHz. In this paper, the completed 250 deg 2 data from l = +25. • 8 to +49. • 7 are presented with a grid spacing of 30 ′′ and a typical rms noise level of ∼ 0.5 K for 12 CO at the channel width of 0.16 km s −1 and ∼ 0.3 K for 13 CO and C 18 O at 0.17 km s −1 . The high-quality data with moderate resolution (∼50 ′′ ), uniform sensitivity, and high spatial dynamic range, allow us to investigate the details of molecular clouds (MCs) traced by the three CO isotope lines. Three interesting examples are briefly investigated, including distant Galactic spiral arms traced by CO emission with V LSR <0 km s −1 , the bubble-like dense gas structure near the H ii region W40, and the MCs distribution perpendicular to the Galactic plane.
We present the first results from the B-fields In STar-forming Region Observations (BISTRO) survey, using the Sub-millimetre Common-User Bolometer Array2 camera, with its associated polarimeter (POL-2), on the James Clerk Maxwell Telescope in Hawaii. We discuss the survey's aims and objectives. We describe the rationale behind the survey, and the questions thatthe survey will aim to answer. The most important of these is the role of magnetic fields in the star formation process on the scale of individual filaments and cores in dense regions. We describe the data acquisition and reduction processes for POL-2, demonstrating both repeatability and consistency with previous data. We present a first-look analysis of the first results from the BISTRO survey in the OMC1 region. We see that the magnetic field lies approximately perpendicular to the famous "integral filament" in the densest regions of that filament. Furthermore, we see an "hourglass" magnetic field morphology extending beyond the densest region of the integral filament into the less-dense surrounding material, and discuss possible causes for this. We also discuss the more complex morphology seen along the Orion Bar region. We examine the morphology of the field along the lower-density northeastern filament. We find consistency with previous theoretical models that predict magnetic fields lying parallel to low-density, non-self-gravitating filaments, and perpendicular to higher-density, self-gravitating filaments.
A deep [S ii] kk6717/6731 wide-field survey of Herbig-Haro (HH) objects has been carried out in two fields toward the R CrA molecular cloud using the ESO/MPG 2.2 m Wide Field Imager. Twelve new HH objects, many of which consist of several condensations or knots, have been discovered, and new details of the known HH objects have been revealed. Combining the results of previous optical, infrared, and millimeter-wavelength observations, the possible exciting sources of HH objects in the region are discussed. On the basis of the previously known and newly discovered HH objects, at least five HH flows in the region around R CrA and at least two outflows in the region around VV CrA can be identified. In combination with the previously detected molecular outflows, the HH flows in the R CrA region indicate rather active star formation in the R CrA core in the past 10 5-10 6 yr.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.