Difference between revisions of "BRC Proposal"

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'''Science Background and Context: Star formation'''
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'''Science Background and Context: Star Formation'''
  
 
Few issues in astronomy are more fundamental than understanding stellar processes.  Learning how stars form has been, and will continue to be, the topic of numerous investigations.  Stars are born in nebulae, giant molecular clouds of gas and dust found in abundance within disk components of spiral galaxies.  Star formation may be triggered in a molecular cloud that is already contracting by shock waves from a variety of sources; supernova explosion, ignition of a very hot star nearby, collision with another molecular cloud, or spiral arm shock waves.  A very large cloud typically contracts to form a number of individual stars.  During the processes of accretion, self-gravitation, and differentiation, protostars are shielded within their nebula, leading to the characterization of nebulae as “stellar nurseries”.  During these stages protostars are thought to be very luminous and look like cool red stars, however this stage is not visible to us.  The dust cocoon absorbs most of the visible radiation surrounding the protostar; the nebula itself obscures and visual component from our view.  However, the energy from the protostar warms the dust, which then reradiates the energy as infrared radiation.  Thus, protostars are visible within their nebula at infrared wavelengths, but are not visible through optical telescopes.  Excess infrared signatures may indicate the existence of an accompanying accretion disk.  Jets from hidden protostars may also announce the presence of the still hidden protostar.
 
Few issues in astronomy are more fundamental than understanding stellar processes.  Learning how stars form has been, and will continue to be, the topic of numerous investigations.  Stars are born in nebulae, giant molecular clouds of gas and dust found in abundance within disk components of spiral galaxies.  Star formation may be triggered in a molecular cloud that is already contracting by shock waves from a variety of sources; supernova explosion, ignition of a very hot star nearby, collision with another molecular cloud, or spiral arm shock waves.  A very large cloud typically contracts to form a number of individual stars.  During the processes of accretion, self-gravitation, and differentiation, protostars are shielded within their nebula, leading to the characterization of nebulae as “stellar nurseries”.  During these stages protostars are thought to be very luminous and look like cool red stars, however this stage is not visible to us.  The dust cocoon absorbs most of the visible radiation surrounding the protostar; the nebula itself obscures and visual component from our view.  However, the energy from the protostar warms the dust, which then reradiates the energy as infrared radiation.  Thus, protostars are visible within their nebula at infrared wavelengths, but are not visible through optical telescopes.  Excess infrared signatures may indicate the existence of an accompanying accretion disk.  Jets from hidden protostars may also announce the presence of the still hidden protostar.

Revision as of 22:02, 26 February 2011

Instructions

2011 proposal instructions

Background on Star Formation

STUFF HERE IS GENERAL OVERVIEW OF STAR FORMATION IN GENERAL. textbooks, overview articles, good things for general knowledge.

Luisa's tutorial on star formation from cool cosmos


Notes from a U of Oregon lecture on star formation ... not as good as Luisa's lecture notes but a good launching point ... http://abyss.uoregon.edu/~js/ast122/lectures/lec13.html

A more detailed explanation of Star Formation from a textbook. There's more math here than we'll need. File:SF.pdf --CJohnson 11:05, 1 February 2011 (PST)


Target Selection

STUFF HERE PERTAINS TO SPECIFIC TARGET SELECTION. why we should do one region versus another, why some regions should be dropped. high-level stuff right here; links below go to stuff specific to each target.

The list of sources that Lori suggests we consider are here:

Let's collect information on literature references for each of these. Look in both ADS and SIMBAD for papers and previously known sources within about 30' 10' of these positions.


Help on: Basic Literature Searching -- Advanced Literature Searching -- Getting data from other wavelengths -- Guide to NITARP participants for use of the wiki


CONCLUSION OF VOTES: we should do BRC 27 AND BRC 34! but we can mention in the proposal something like "we have a few other targets that we can study instead or in addition to the targets discussed here, should the analysis go faster than anticipated."

papers from discussion on the phone 16:35, 23 February 2011 (PST)


STUFF BELOW THIS LINE IS MEAT/DRAFT TEXT FOR PROPOSAL ITSELF.

Introduction/Background

the formal reference to lori's poster is here: http://adsabs.harvard.edu/abs/2011AAS...21725815A --Rebull 16:22, 23 February 2011 (PST)


http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1655856 Proceedings of the International Astronomical Union (2007), 3: 164-165 DOI: 10.1017/S1743921307012823 (About DOI) Published online: 25 Jan 2008 Low-mass star formation in bright rimmed clouds V. Migenesa, M. A. Trinidada, R. Valdettaroa, F. Pallaa and J. Branda --Sartore 16:02, 23 February 2011 (PST)

A&A 388, 172-178 (2002) DOI: 10.1051/0004-6361:20020451 The embedded star clusters in the nebulae NGC 2327 and BRC 27 in Canis Majoris R1 J. B. Soares and E. Bica Universidade Federal do Rio Grande do Sul, IF, CP 15051, Porto Alegre 91501-970, RS, Brazil (Received 11 February 2002 / Accepted 21 March 2002 )--Sartore 16:03, 23 February 2011 (PST)

A&A 426, 535-545 (2004) DOI: 10.1051/0004-6361:20040226 A radio and mid-infrared survey of northern bright-rimmed clouds L. K. Morgan, M. A. Thompson, J. S. Urquhart, G. J. White and J. Miao

Centre for Astrophysics and Planetary Science, School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NR, UK --Sartore 16:03, 23 February 2011 (PST)


Science Background and Context: Star Formation

Few issues in astronomy are more fundamental than understanding stellar processes. Learning how stars form has been, and will continue to be, the topic of numerous investigations. Stars are born in nebulae, giant molecular clouds of gas and dust found in abundance within disk components of spiral galaxies. Star formation may be triggered in a molecular cloud that is already contracting by shock waves from a variety of sources; supernova explosion, ignition of a very hot star nearby, collision with another molecular cloud, or spiral arm shock waves. A very large cloud typically contracts to form a number of individual stars. During the processes of accretion, self-gravitation, and differentiation, protostars are shielded within their nebula, leading to the characterization of nebulae as “stellar nurseries”. During these stages protostars are thought to be very luminous and look like cool red stars, however this stage is not visible to us. The dust cocoon absorbs most of the visible radiation surrounding the protostar; the nebula itself obscures and visual component from our view. However, the energy from the protostar warms the dust, which then reradiates the energy as infrared radiation. Thus, protostars are visible within their nebula at infrared wavelengths, but are not visible through optical telescopes. Excess infrared signatures may indicate the existence of an accompanying accretion disk. Jets from hidden protostars may also announce the presence of the still hidden protostar.

Bright Rimmed Clouds (BRC’s) are clouds that have experienced compression due to an external ionization shock, which served to focus the neutral gas into compact globules (Migenssa et.al.(2008)). These clouds generally have a radius of less than 0.5 pc, with an average mass near (or exceeding) 100 solar masses. Attention has turned to BRC’s as potential loci for star formation; their “speck globules” and “cometary globules” presenting interesting sites for possible star formation. Whether external ionization shocks compress the neutral gas into compact globules or bright rims, the boundary between neutral gas and gas ionized by incident photons is thought to be rich in potential sites for star formation. Drawn from the lists of Sugitani, Fukui, and Ogura (1991), and Sugitani and Ogura (1994), Allen et.al.(2011) imaged 32 of the closest bright-rimmed clouds located at estimated distances d < 1.2 kpc, finding young stellar objects in 75% of the clouds they studied.

Using Spitzer Space Telescope Archival Data we propose to conduct further examinations of BRC 27 and BRC 34 to search for additional Young Stellar Objects. BRC 27 is located in the molecular cloud Canis Majoris R1. BRC 34 has a variety of features worthy of deeper examination; dark nebulae, molecular and IC clouds, emission stars, and IR sources. Allen et.al.(2011) found one Class I protostar in BRC 27 and 34. Far more Class II T-Tauri stars were found in those same BRC's. Beyond that, these two BRC’s have not been well studied. We would like to search for undiscovered Young Stellar Objects. We believe there are more YSO’s to find in these BRC’s using Spitzer Space Telescope archival data in a variety of wavelengths.

--Sartore 13:58, 26 February 2011 (PST)

BRC 27: John

BRC 34: Marcella

... drop what you have here ...

Analysis Plan

mark, please also dip into the SHA (ops not i&t! :) ) to see what data are available, specific AORKEYs, etc. we'll need to put that in the proposal too. --Rebull 16:12, 23 February 2011 (PST)


--Legassie 15:53, 23 February 2011 (PST)

Available Data

  • Archival Spitzer IRAC 4 bands & MIPS (Programs TBD)
  • 2MASS
  • MSX
  • Optical?
  • Spot visualization of Spitzer data?

Data Reduction

  • Photometry will be obtained using data reduction tools such as Aperture Photometry Tool (APT)
  • Mosaics will be created using MOPEX

Analysis Plan

  • Plan is to combine all available data and examine properties of previously known YSOs (Allen et al 2010) as well as look for new YSOs
  • Looking for infrared excess emission from material surrounding new stars will be the main focus of the research
  • Using photometry measurements, team will generate and examine several diagrams, looking for infrared excesses
    • Color-Color diagrams
    • Color-Magnitude diagrams
    • Spectral Energcy Distribution (SED) plots
  • Analysis will also involve looking at actual optical and infrared images

Tools

  • MOPEX - to create mosaics (Makovoz & Marleau 2005)
  • Aperture Photometry Tool (APT) - to obtain photometry (Laher et al. 2010)
  • MS Excel – to generate data diagrams (color-color, SEDs)

Education and Outreach

Starting with a general introduction to the physical properties of light, students and teachers will collaborate to synthesize observations across the spectrum. They will compare images obtained by IRAC, MIPS and IRAS to learn about spatial resolution. Evidence will be presented to help students understand how the universe is changing, how stars and planets are forming, and how stars evolve from birth to eventual death. Combining images at different wavelengths, students will be able to produce false-color images that enhance the features of young stellar objects and the ISM composition and structures.

A key initiative in science education is authentic research. Using archival Spitzer data in this project allows our students the experience to assume an active role in the process of project development, teamwork, data collection and analysis, interpretation of results, and formal scientific presentations. They will learn about the instrumentation used in infrared astronomy and the necessity of space-based telescopes. Students and teachers will use spreadsheet and graphing programs to generate color-color plots and color-magnitude diagrams to determine stellar properties. These activities will be age-appropriate and will be shared with other teachers through educational presentations at state, regional and national conferences.

Communication is an important tool in science education. Modeling the collaboration of scientists across the world, students will use the CoolWiki to post their queries and hold on-line discussions about their analysis methods and subsequent results. The CoolWiki is designed to provide a place for teachers, students, and scientists to interact and share the materials they've developed, work on new materials, and collaborate on current projects. The wiki also provides a resource for other teachers to learn how to use the materials we've developed. The wiki is a dynamic place, constantly changing and growing. (need to develop this thought further...)

Team Spitzer at Breck School Similar to previous NITARP/Spitzer projects, a small cadre of Breck School juniors and seniors will work together on this BRC project. Beginning with short tutorials on the general principles of star formation, scientific articles will be read and discussed in weekly "brown-bag discussions." Once the students feel comfortable with the material, the team will be divided into pairs to work cooperatively on the data analysis.


Marcella:

John:

Diane:

... drop one paragraph per teacher here ...

--CJohnson 19:40, 22 February 2011 (PST)

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