Trifid Nebula

In this exercise, you will be presented with background information on the topic of interest, including lecture notes. After reviewing that material, you should download and print out the PDF of the problem. Finally with the problem in front of you, open up the image tool and use it to analyse the images in order to answer the questions on the PDF. Write on the printout of the problem and bring it to class.

Components

Background

M20

Introduction

The Trifid nebula (also know as M20 or NGC 6514) is one of the most spectacular optical HII regions in the sky. The red emission nebula contains a bright blue star cluster near its center: it glows red because the ultraviolet light of the stars ionizes the hydrogen gas, which then recombines and emits the characteristic red hydrogen-alpha light. Further out, when the radiation from these hot young stars becomes too weak to ionize hydrogen, the gas and dust instead glows by reflecting the original blue light. M20 is in the constellation of Sagittarius and its angular diameter is approximately 6 arcminutes, which corresponds to 2.8 pc at a distance of 1.67 kpc. The box in the lower left hand corner identifies an interesting region (shown as a close up on the next page) containing dense gas and dust clouds, as well as an jet.

Trifid Nebula Close-Up

Trifid Nebula Close-Up

This Hubble telescope image shows a close-up view of the Trifid Nebula that reveals a stellar nursery being torn apart by radiation from a nearby, massive star. The picture also provides a peek at embryonic stars forming within an ill-fated cloud of dust and gas, which is destined to be eaten away by the glare from the massive neighbor. This stellar activity is a beautiful example of how the life cycles of stars like our Sun are intimately connected with their more powerful siblings. The region of this image is shown as the box on the image in the previous page. The box at the top of this image shows a region of a jet shown in the next page.

Trifid Nebula Jet

Trifid Nebula Jet

This image shows a very zoomed region (the region of this image is shown as the box in the previous page) that shows a remarkable jet-like structure, called HH 399. For convenience, the jet is rotated such that it lies in the horizontal direction. This jet is emanating from a young protostellar source that is obscured by dust clouds and indicates that a new generation of star formation induced by the nebula.

PDF of Assignment

Print out the following PDF file, print out and answer using the interactive tool below.

PDF of Assignment

Interactive Measurement of Jet Motion

Observations of the jet have been made in two different epochs (June 2002 and September 1997). The H α line images were carefully aligned using 9 bright stars. The purpose of this exercise is to determine how much the jet has moved during this time. The link below will open the comparison tool in a separate window that allows you to determine the motion of the jet between the two observations.

Open Interactive Measurement Tool