Useful pages: CG4 team page: http://coolwiki.ipac.caltech.edu/index.php/CG4_Current_Research_Activities final proposal now linked in from proposal page.
Bigger picture and goals page (agendas for visit, etc): http://coolwiki.ipac.caltech.edu/index.php/CG4_Bigger_Picture_and_Goals
Summer visit logistics page: http://coolwiki.ipac.caltech.edu/index.php/CG4_Summer_visit
Page with questions specifically for you and our data: http://coolwiki.ipac.caltech.edu/index.php/Working_with_CG4%2BSA101
This is to be used in conjunction with the more generic instructions here: http://coolwiki.ipac.caltech.edu/index.php/Working_with_L1688
Please see a very raw first cut at writing the Introduction and Background for The Proposal. You already feel free to edit, right? This gives a place to start, or a decision to start over. --Mallory 12:43, 3 February 2010 (PST)
Draft (Can't find name & time stamp on this page. Many additions and heavily edited 7 Feb. 2010).
STAR FORMATION IN CG4
What factors can make Nebulae, ordinary clouds of hydrogen and helium and perhaps some tritium gas, plus dust of common silicate compounds, which appear widely throughout the plane of The Milky Way/or any galaxy, overcome the plentiful disruptive forces in their environments, and form stars? When can the classically interpreted Force of Gravity, overwhelm the dispersive effect of radiation, and force collapse into a star, on a cloud of gas and dust?
What is the importance of Young Stars? On the local scale, even small stars usually form discs, which often coalesce into planets; some may be Earth-Like planets. On a more grand scale, formation and evolution of different types of stars, changes gas and dust and chemical composition of Galaxies; which are the structural components of the universe, i.e. Galaxie Changes, causes evolution of the Universe.
The Cometary Globules CG4 (R. A. 7 degrees 34’ 9”, Dec -56 degrees, Ecliptic Co-ords.) is an excellent site to study formation of stars. Using this Locale, we will attempt to answer three questions: Will Stars Form Here? If So, Is Their Formation Triggered? and, Has a Whole Cluster Been Formed?
The CG4- Gum Nebula environment is chosen because the area is visually, photometrically dense with star-forming material. USNO http://www.nofs.navy.mil/data/fchPix used to determine opacity of nebula and optical magnitude. Through our collaborator J.S. Kim (U. AZ.) we have access to CG4 optical data in BVRI filters from the CTIO 0.9m. Extrapolating from this info may permit us to predict where and why new stars form. We plan to use Spitzer MIPS data, available in far IR 24, 70, 160 mm wavelengths to detect warm/collapsing gas clouds/protostars. Additional indication of YSOs is available by using POSS 8000 mm data to reveal the near IR signature of excess IR coming from a newly-forming star. Spitzer data is especially well-suited to detect the presence of PAHs on the surfaces of collapsing dust/gas clouds, in 6 & 8 mm, and to comfirm YSOs' excess gases BiPolar outflow in 4.6 and 5.5 mm IR. Using Spectral Energy Distribution data, newly formed stars can be both identified and classified. The primary goal of this research: Determination of Star Formation in CG4, can be achieved.
Conditional on the outcome of the first research step; The second step in our research is to determine whether this is Triggered Star Formation.(See “Spitzer Observations of IC 2118.) The outcome of this important research question will help to determine the Rate of Star Formation in the Universe. The presence of both O & B superstars, copious UV and gamma emitters, plus Supernova Remnants indicating stupendous interstellar explosions, suggest an energetic nebular environment. We verified this using Multiwavelength Photometric Studies, similar to (Kim,S. et al, "Triggered Low Mass Star Formation in the Gum Nebula", 2003). A similar environment, see Spitzer Observations of IC 2118, confirm this idea. The Skyview Telescope (http://skyview.gsfc.nasa.gov) shows radiation at all wavelengths and images at all wavelengths, of excited gas/dust in the selected region. Through our collaborator J.S. Kim (U. AZ)we have access to X-ray data from XMM, Epic and PN images that cover CG4. X-ray + UV presence may have triggered star formation by providing compression pressure onto collapsing nebula gas-knots, or destroyed them by photo-evaporation.
Skyview Telescope (http://skyview.gsfc.nasa.gov)) shows radiation at all wavelengths and images at all wavelengths of excited gas/dust in the selected region. In addition, O & B Stars, as well as supernova remnants of their cousin stars, reside in the nearby Vela Nebula.
Our Final Question related to Star Formation in CG4, "Has a Whole Star Cluster Been Formed", has to be approached carefully, since it is so easy to confuse a foreground/background star with actual Cluster Members. The finest tool to accomplish the identification of Stars Which Are Cluster Members, resides on the IPAC website. What the techniques boils down to, is to determine all YSOs in an area, and be sure they are all the same age. If they are the same age, it is likely they are all members of the same cluster. Some characteristics they should all have/all have in common, are: IR excess; flaring/in X-rays; flaring /in radio/emmission from stellar active regions, like Sun Spots; BiPolar outflows (detectable in IR & optical as emitted jets); emission lines (from accreting matter); variability (not quite in equilibrium yet); fast rotation rate (concervation of Angular Momentum); UV flaring/mass accretion; spatial location huddled together; similar brightness; common spatial motion as they glide through space loosely gravitationally bound together.
Spitzer is good at determining these qualities of stars. It is so sensitive that it can see nearly to the 'edge' of the Universe, and integrate data in just a handful of seconds. Further, Spitz, will see the excess IR from the Planatary Disc of a newly formed star, before it gets dissipated, and that will record as a Spare Tire IR Excess. Chandra and XMM data will be helpful in detecting X-ray flares due to large magnetic field, from rapid rotation inducing emission flares in X-ray wavelength.
Proposal for CG4 Group
Goal: We are looking for new young stellar objects (YSO) in the cometary nebula CG4 in Puppis. These objects will tell us about cometary globules and conditions within them. We will find information about the structures in the globule, their history and possibly their future.
Stars form in regions of dense dust and gas in the interstellar medium (ISM). The process is.... (See Carolyn's explaination above.)
Cometary globule CG4 is approximately 450 parsec away. It is a part of a larger structure in the Milky Way. It is one of a number of cometary globules in the area pointed away from a common center, possibly the Vela supernova remnant. CG4 is a nearby and dramatic cometary globule, so it is of interest to scientists and the public. Recent visible and visible/infrared mosaics have been featured in Astronomy Magazine and Science News Magazine.
Method: Our team will use Spitzer IRAC and MIPS data (programs 202, 462, 20714), 2MASS data, and XMM-Newton x-ray data. We expect to find the previously known YSOs (Reipurth and Petersson 1993) and additional YSOs in star-forming regions. We will find other candidate objects using infrared excess across different wavelengths. There will be some non-members in this candidate group. Along with YSOs in the cluster, we expect to find extragallactic sources (active galactic nuclei anything else ?). We will use x-ray data, phtometric data and astrometry to determine cluster membership and separate YSOs from other objects with IR excess.
We will use x-ray data from the . We will use astrometry to find proper motion using the Digitized Sky Survey plates and more recent images from CTIO 0.9m telescope.
We propose using IRAC, MIPS and 2MASS data archives along with XMM-Newton satellite data, photometric data (BVRI) from the CTIO 0.9m telescope and astrometric data from the Digitized Sky Survey and more recent images with the CTIO 0.9m telescope to investigate:
1. Star formation; look for likely cluster member stars with infrared excesses, and
2. characterize this young star population by obtaining colors and estimates of masses and ages;
3. study the distribution of stars, compare the young star population, distribution, and age to other similar sites of star formation.
DRAFT CG4 YSO Abstract DRAFT
We propose looking for new young stellar objects (YSOs) in the cometary nebula CG4 in Puppis. We will attempt to answer the following questions: (1) Will stars form here? (2) What triggers star formation? (3) Has a cluster formed? We will use x-ray data from XMM-Newton. We will use astrometry to find proper motion using the Digitized Sky Survey plates and more recent images from CTIO 0.9m telescope. Cometary globule CG4 is approximately 1300 parsecs away. It is one of approximately 30 cometary globules in the Gum Nebula (Choudhury and Bhatt 2008). These globules are pointed generally radially outward from the center of the Vela OB2 association. The CG4- Gum Nebula environment is chosen because the area is visually, photometrically dense with star-forming material. (Reipurth 1993?) CG4 is a nearby and dramatic cometary globule, so it is of interest to scientists and the public. Recent visible and visible/infrared mosaics have been featured in Astronomy Magazine and Science News Magazine. Our team will use Spitzer IRAC and MIPS data, 2MASS data, and XMM-Newton x-ray data. We expect to find the previously known YSOs (Reipurth and Petersson 1993) and additional YSOs in star-forming regions. We will find other candidate objects using infrared excess across different wavelengths. There will be some non-members in this candidate group. Along with YSOs in the cluster, we expect to find extragalactic sources (i.e., active galactic nuclei). We will use x-ray data, photometric data and astrometry to determine cluster membership and separate YSOs from other objects with infrared excess.