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PdBI high-spatial resolution CO observations combined with near-infrared H2 data disentangle at least 7 (maybe even 9) molecular outflows in the massive star-forming region IRAS19410+2336. Position-velocity diagrams of the outflows reveal…

Astrophysics · Physics 2009-11-07 H. Beuther , P. Schilke , T. Stanke

We present results of the narrow-band Halpha and [SII] imaging survey of Mon R1 association, performed with the 1 m Schmidt telescope of the Byurakan Observatory. Our observations covered one degree field near the center of the association.…

Solar and Stellar Astrophysics · Physics 2020-12-02 T. A. Movsessian , T. Yu. Magakian , S. N. Dodonov

Young stellar objects are thought to commonly undergo sudden accretion events that result in a rise in bolometric luminosity. These outbursts likely coincide with the onset of planet formation, and could impact the formation of planets. The…

Solar and Stellar Astrophysics · Physics 2024-09-10 Jenny K. Calahan , Edwin A. Bergin , Merel van't Hoff , Ke Zhang , Nuria Calvet , Lee Hartmann

We present Spitzer Space Telescope IRAC and MIPS observations toward a sample of nine high-mass star forming regions at a distance of around 2 kpc. Based on IRAC and MIPS 24 $\mu$m photometric results and 2MASS JHKs data, we carry out a…

It has been suggested that besides stellar companions, substellar objects in close orbits may be able to trigger mass loss in a common envelope phase and form hot subdwarfs. In an ongoing project we search for close substellar companions…

Solar and Stellar Astrophysics · Physics 2011-12-14 S. Geier , L. Classen , P. Bruenner , K. Nagel , V. Schaffenroth , C. Heuser , U. Heber , H. Drechsel , H. Edelmann , C. Koen , S. J. O'Toole , L. Morales-Rueda

We suggest that a high proportion of brown dwarfs are formed by gravitational fragmentation of massive, extended discs around Sun-like stars. We argue that such discs should arise frequently, but should be observed infrequently, precisely…

Astrophysics · Physics 2009-11-13 Dimitris Stamatellos , Anthony P. Whitworth

Hot subluminous stars (sdO/B) are evolved low mass stars originating from red giants that lost their envelope almost entirely. The multitude of observed phenomena imply that several pathways may form hot subdwarfs, most involving close…

Solar and Stellar Astrophysics · Physics 2026-04-01 Ulrich Heber , Lennard Kufleitner , Matti Dorsch , Marilyn Latour , Harry Dawson , Fabian Mattig , Stephan Geier

We present maps of seven sources selected from Klaassen & Wilson (2007a) in SiO (J=8-7) and HCO$^+$ and H$^{13}$CO$^+$ (J=4-3) which were obtained using HARP-B on the James Clerk Maxwell Telescope. We find that four out of our seven sources…

Astrophysics · Physics 2009-11-13 P. D Klaassen , C. D Wilson

We have measured high-precision parallaxes for a large sample of candidate young (~10-100 Myr) and intermediate-age (~100-600 Myr) ultracool dwarfs, with spectral types ranging from M8 to T2.5. These objects are compelling benchmarks for…

Solar and Stellar Astrophysics · Physics 2015-06-15 Michael C. Liu , Trent J. Dupuy , Katelyn N. Allers

We present some results from a systematic survey for disks around spectroscopically identified young brown dwarfs and very low mass stars. We find that ~75% of our sample show intrinsic IR excesses, indicative of circum(sub)stellar disks.…

Astrophysics · Physics 2007-05-23 Michael C. Liu

The FU Orionis (FUor) or EX Orionis (EXor) phenomenon has attracted increasing attention in recent years and is now accepted as a crucial element in the early evolution of low-mass stars. FUor and EXor eruptions of young stellar objects…

Solar and Stellar Astrophysics · Physics 2012-06-26 J. P. Ninan , D. K. Ojha , B. C. Bhatt , K. K. Mallick , A. Tej , D. K. Sahu , S. K. Ghosh , V. Mohan

Substellar objects, like planets and brown dwarfs orbiting stars, are by-products of the star formation process. The evolution of their host stars may have an enourmous impact on these small companions. Vice versa a planet might also…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Geier , H. Edelmann , U. Heber , L. Morales-Rueda

The high spatial and spectral resolution offered by the new generation of infrared spectrometers at ESO is optimally suited for the observational study of outflows from young stellar objects. Models of interstellar shock waves would benefit…

Astrophysics · Physics 2009-11-10 R. Liseau

Star formation can produce bubbles and outflows, as a result of stellar feedback. Outflows and bubbles inject momentum and energy into the surrounding interstellar medium, and so are related to the overall energy balance of the molecular…

Astrophysics of Galaxies · Physics 2023-02-15 Yan Duan , Di Li , Paul F. Goldsmith , Laurent Pagani , Tao-Chung Ching , Shu Liu , Jinjin Xie , Chen Wang

While wide-field surveys of M31 have revealed much substructure at large radii, understanding the nature and origin of this material is not straightforward from morphology alone. Using deep HST/ACS data, we have derived further constraints…

We present results of continuum and spectral line observations with ALMA and 22 GHz water (H$_2$O) maser observations using KaVA and VERA toward a high-mass star-forming region, G25.82-0.17. Multiple 1.3 mm continuum sources are revealed,…

(Abridged) We have completed the first systematic survey for disks around spectroscopically identified young brown dwarfs and very low mass stars. We have obtained L'-band (3.8 um) imaging for 38 very cool objects in IC 348 and Taurus. Our…

Astrophysics · Physics 2008-11-26 Michael C. Liu , Joan Najita , Alan T. Tokunaga

A search for young substellar objects in the rho Oph cloud core region has been made using the deep-integration Combined Calibration Scan images of the 2MASS extended mission in J, H and Ks bands, and Spitzer IRAC images at 3.6, 4.5, 5.8…

Solar and Stellar Astrophysics · Physics 2015-05-19 Kenneth A. Marsh , Peter Plavchan , J. Davy Kirkpatrick , Patrick J. Lowrance , Roc M. Cutri , Thangasamy Velusamy

The cosmic star formation histories are evaluated for different minimum masses of the initial halo structures, with allowance for realistic gas outflows. With a minimum halo mass of 10^{7} - 10^{8} M_odot and a moderate outflow efficiency,…

Astrophysics · Physics 2009-09-15 Frederic Daigne , Keith A. Olive , Joe Silk , Felix Stoehr , Elisabeth Vangioni

We use two 4.5micron Spitzer (IRAC) maps of the NGC 1333 region taken over approx. 7 yr interval to determine proper motions of its associated outflows. This is a first, successful attempt at obtaining proper motions of stellars outflow…

Astrophysics of Galaxies · Physics 2015-06-12 A. C. Raga , A. Noriega-Crespo , S. J. Carey , H. G. Arce