Download or read book Insights Into High Mass Star Formation from Methanol Maser Observations written by Hontas Freeman Farmer and published by . This book was released on 2013 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 well understood, details of the formation of stars with masses eight times that of our Sun or greater, the so-called high mass stars, remain a mystery. Being compact and bright sources, masers provide an excellent way to observe high mass star forming regions. In particular, Class II methanol masers are found exclusively in 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 methanol maser in the outflow, as is known from observations during the last twenty years. In our first model, the H2O masers trace the linear extent of the outflow. In our second model, the H2O masers are located in a circumstellar disk. In our third model, the H2O masers are located in one or more outflows near the terminating shock where the outflow impacts the ambient interstellar medium. Together, these models reiterate the utility of coordinated high angular resolution observations of high mass star forming regions in maser lines and associated star formation tracers.
Download or read book Massive Star Formation written by Henrik Beuther and published by . This book was released on 2008 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Astrophysical Masers and Their Environments IAU S242 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2008-02-14 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrophysical masers, naturally occurring microwave and radio-wave emissions, provide an important tool to investigate astrophysical environments. Several thousand maser sources have been observed in the interstellar medium and star formation regions, in the expanding winds from evolved stars, in the compressed shells of supernovae remnants, in comets and in the centers of galaxies. Masers are also useful for studying the structure and dynamics of our own galaxy, while masers in other galaxies are now used for cosmological studies and studies of galactic nuclei. This volume contains the latest research on the topic as presented at IAU Symposium 242, only the third international symposium on astrophysical masers. Over 125 astronomers from 18 different countries gathered in Alice Spring, Australia, for discussions on maser research.
Download or read book Astrophysical Masers IAU S336 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2018-09-13 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes state of the art observations and theories pertaining to astrophysical masers and their environments, for graduate students and researchers.
Download or read book High Resolution Observations of 36 GHz Class I Methanol Masers at Sites of 6 7 GHz Class II Methanol Masers in Star Forming Regions written by Jared Hennen and published by . This book was released on 2012 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we present high angular resolution data on 36 GHz Class I methanol masers associated with sites of 6.7 GHz Class II methanol masers. We observed twenty-three 36 GHz Class I methanol masers in seven star forming regions with the Jansky Very Large Array radio telescope. Our observations have made possible the first high angular resolution maps of 36 GHz masers in several star forming regions, and demonstrated cases where the morphology is highly suggestive of arcs and other structures known to be found at shock interfaces in such regions. The two classes of methanol masers are created through different excitation processes, and occur in different parts of star forming regions. We find that strong 6.7 GHz Class II maser sites are likely associated with weak 36 GHz Class I masers, in agreement with a similar anti-correlation between 44 GHz Class I and 6.7 GHz Class II methanol masers in the literature. However, there is a correlation between 95 GHz Class I and 6.7 GHz Class II masers in the literature. This points to the need for a larger set of high angular resolution data and improved theoretical models of methanol maser pumping and propagation. We find that the center velocities (vLSR) of the observed 36 GHz masers are quite close to the vLSR of 6.7 GHz masers, and in some cases may be closer to the systemic velocity of the region than the vLSR of the 6.7 GHz masers. This could be due to such 36 GHz masers being located at the base of outflows close to the location of the protostar. Finally, comparison of spectral profiles indicates that the strongest 36 GHz masers may lie closer to the 6.7 GHz masers. In summary, such high angular resolution observations that allow for the comparison of the two classes of methanol masers provide a powerful tool to study star forming regions.
Download or read book VLBI Observations of 6 7 and 12 2 GHz Methanol Masers Toward High Mass Star forming Regions written by V. Minier and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Astrochemistry written by Olivia Harper Wilkins and published by American Chemical Society. This book was released on 2021-07-21 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: The answers to some of the most fundamental questions in science lie between the stars, in molecular clouds that serve as celestial laboratories. Disentangling the chemistries in extraterrestrial environments can provide clues about how planets form and shed light on problems in terrestrial chemistry that are difficult to investigate in the lab, and even the origins of life. Astrochemistry takes you on a tour of the molecular universe through time and space, starting with the emergence of matter about 13.8 billion years ago. From there, the tour visits the interstellar medium, with an emphasis on molecular clouds where stars are born. It then goes through different evolutionary stages of stars and planets – and the chemistry that emerges alongside them – before ending in our own solar system, where you will learn about chemical delivery by objects such as comets and meteorites.
Download or read book Revista Mexicana de Astronom a Y Astrof sica written by and published by . This book was released on 2003 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemistry as a Diagnostic of Star Formation written by National Research Council Canada and published by NRC Research Press. This book was released on 2003 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication contains presentations & poster papers of a conference that focussed on the many aspects of astrochemistry related to star formation. Topics covered include: the next generation of telescopes & detectors; studies of fundamental chemical processes both in the lab & in the field; an exploration of the connections between chemistry & physics in star-forming regions; the unique problems of high-mass star formation; the formation of hydrogen; deuterated molecules; molecular depletion; observations & modelling of embedded protostars; accretion disks & circumstellar disks; interstellar dust; and the chemistry, physical conditions, & structure of dark clouds. Includes indexes of subjects, authors, & astronomical objects.
Download or read book Science with the GTC 10 m Telescope written by José Miguel Rodríguez Espinoza and published by . This book was released on 2003 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methanol Masers as Signposts of Star Formation and VLBI Observations of Coronal Emission from Young Stars written by Michele R. Pestalozzi and published by . This book was released on 2004 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radio Emission Toward Regions of Massive Star Formation in the Large Magellanic Cloud written by Adam Johanson and published by . This book was released on 2015 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four regions of massive star formation in the Large Magellanic Cloud (LMC) were observed for water and methanol maser emission and radio continuum emission. A total of 42 radio detections were made including 27 new radio sources, four water masers, and eight compact HII regions. The lobes of a radio galaxy were resolved for the first time, and the host galaxy identified. Seven sources were associated with known massive young stellar objects (YSOs). A multi-wavelength analysis using both the infrared and radio spectrum was used to characterize the sources. Mid-infrared color-magnitude selection criteria for ultracompact HII (UCHII) regions in the LMC are presented, yielding 136 UCHII region candidates throughout that galaxy. New maser detections identified two previously unknown massive YSOs. No methanol masers were detected, consistent with previous studies and supporting the hypothesis that the LMC may be deficient in these molecules. These discoveries contribute to the history of star formation in the LMC, which will lead to a better understanding of star formation in the Milky Way and throughout the universe.
Download or read book High Resolution Observations of Masers in Star Formation Regions and Evolved Stars written by Jiyune Yi and published by . This book was released on 2005 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding the Earliest Stages of High mass Star Formation written by Alana Rivera Ingraham and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Massive Star forming Regions Across the Galaxy written by Kazi Lucie Jessica Rygl and published by . This book was released on 2010 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Alcohols Advances in Research and Application 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alcohols: Advances in Research and Application: 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Alcohols. The editors have built Alcohols: Advances in Research and Application: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Alcohols in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Alcohols: Advances in Research and Application: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Study of the Earliest Stages of High mass Star Formation Through High angular Resolution Spectral Line Observations written by Carlos M. Poventud Estrada and published by . This book was released on 2009 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
