HD 209458b, Messier 1, and Messier 104

Observatory / Course Archives / ASTR 110 Fall 2019 / Van Appledorn

HD 209458b (Image Credits: NASA, European Space Agency, Alfred Vidal-Madjar (Institut d'Astrophysique de Paris, CNRS))
Messier 1 (Image Credit: NASA, ESA, J. Hester, A. Loll (ASU))
Messier 104 (Image Credits: NASA and the Hubble Heritage Team (STScI/AURA))

HD 209458b

HD 209458b, sometimes referred to as Orsis, is an exoplanet. Exoplanets are any planet that orbits a star other than our sun. They are very small compared to stars and galaxies so it is often impossible to see them with a telescope. There are two ways in which astronomers can detect exoplanets around stars: the Doppler effect and transit method. The Doppler effect looks for stars that “wobble” to reveal a planet that has a gravitational effect on its star. The transit method looks for dimming in star light when a planet passes between earth and the star to block some of that light. Sometimes it is possible for telescopes to take images of the exoplanet’s silhouette as it passes between its star and earth. The Kepler Space Telescope is used to search for exoplanets using these methods. Its goal is to find stars similar to our sun with earth like planets orbiting them. So far more than 22 percent of sun like stars had been found to have earth like planets orbiting them.

Discovered in 1999, HD 209458b is not only one of the earliest exoplanets discovered but is also the first exoplanet where scientists were able to detect the chemical make up of its atmosphere. The HD 209458 system is located 150 light years away from Earth in the Pegasus constellation and was discovered using the transit method. This planet is a jovian planet (gas giant) with a mass of 0.69 Jupiter masses. It has a very small semimajor axes. Its close proximity to its star makes it a “hot Jupiter.” Some of the gasses detected include carbon dioxide, hydrogen, methane, helium, oxygen, and water vapor.

Messier 1

Messier 1 is a nebula. Nebulae often form from gas and dust being ejected from a supernova which is the explosion of a massive star. Nebulae are known as the birthplace of stars because stars form from the gasses within them. This is why they are referred to as star nurseries. Astronomers began discovering nebulae in the 1600s and by the end of the 1700s 2,510 nebulae had been discovered. Some common types of nebulae include emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants which is what Messier 1 is.

Messier 1 is also known as the Crab Nebula. It is made up of gas and dust left over from a supernova. The supernova was actually discovered in 1054 when the light from its explosion reached Earth and was so bright that it was even visible during the daytime. The nebula itself was discovered in 1731. It is about 6 lightyears across and located about 6500 light years away from Earth in the Taurus constellation. The nebula consists of mostly hydrogen (orange), neutral oxygen (blue), ionized sulfur (green), and doubly ionized oxygen (red). At its center is a neutron star pulsing radiation in two directions 30 times per second (also known as a pulsar). As it rapidly spins it generates an extremely strong magnetic field the hurdles electrons nearly the speed of light which generates the blue glow at the center. Messier, like many nebulae, will fade and be come invisible eventually. It will only last about tens of thousands to hundereds of thousands of years.

I De Looze, M J Barlow, R Bandiera, A Bevan, M F Bietenholz, H Chawner, H L Gomez, M Matsuura, F Priestley, R Wesson. The dust content of the Crab Nebula. Monthly Notices of the Royal Astronomical Society, Volume 488, Issue 1, September 2019, Pages 164–182, https://doi.org/10.1093/mnras/stz1533

Messier 104

Messier 104 is a lenticular galaxy which consists of a disk and bulge. Lenticular galaxies typically resemble the shape of a magnifying lense and consist of mostly older stars. When viewed face it is easy to mistake them for elliptical galaxies where all the stars have random orbits around the center. The formation of these galaxies is unknown but it is possible that they are the result of interactions between multiple spiral galaxies where the spiral arms were lost and became a uniform disk.

Messier 104 also known as the Sombrero Galaxy is 28 million light years away. It is thought to have a blackhole at its center which is 1 billion solar mass. The disk consists of large outer ring and a smaller inner ring that has been detected with x-ray imagery which feeds into the mass at the center. It is estimated to have nearly 2000 globular clusters. That is 10 times more that the Milkyway. From edge to edge it measures 60,000 light years. The galaxy is located in the Virgo constellation and has a magnitude of 8 which is not visible in the night sky. It is not visible with the naked eye but could be seen through an amateur telescope.

References:

https://spaceplace.nasa.gov/all-about-exoplanets/en/

http://exoplanet.eu/catalog/hd_209458_b/

https://exoplanets.nasa.gov/resources/231/hd-209458b/

https://www.nasa.gov/vision/universe/newworlds/Osiris_leaks.html

https://space-facts.com/exoplanets/

https://www.nasa.gov/multimedia/imagegallery/image_feature_1604.html

https://www.nasa.gov/feature/goddard/2017/messier-1-the-crab-nebula

https://spaceplace.nasa.gov/nebula/en/

http://curious.astro.cornell.edu/observational-astronomy/85-the-universe/supernovae/general-questions/410-how-long-do-supernova-remnants-last-intermediate

https://theplanets.org/nebula-facts/

http://astroa.physics.metu.edu.tr/twn/types.html