ASTRONOMY 301

Introduction to Astronomy

Spring 2009

Discovery of the first planet in the habitable zone around another star. Update May 8, 2009: Originally, it was thought that the planet in the foreground of this artist's impression, which is about 5 times as massive as our Earth, is at just about the right distance from its sun so that water (if there is any present) can be liquid on its surface. The star Gliese 581 is a red dwarf that is only 1 percent as bright as our Sun. At the time, there were two other planets known in the Gliese 581 system. Click on the image to get the associated press release. In a new press release on April 21, 2009, Michel Mayor and his team announce the discovery of the first roughly Earth-mass planet found around a normal, main-sequence star. It is at least 1.9 times the mass of the Earth and is the fourth planet found in this system. It is too close to the star to be favorable for life. But as a result of its discovery, it was possible to improve the calculations of the orbits of the other planets, too. All are a bit closer to the star than we thought. The planet in the foreground is now thought to be too close to the parent star to be plausible for life. But the most massive planet in the system, the banded blue world in this artist's conception, is now shown to be well within the habitable zone. Since it has at least 7 Earth masses, it was probably once a Neptune-like giant planet. Having migrated into the habitable zone, it may now be the first "water world" that we have discovered. Of all the exoplanets found so far, it is the most likely one to have life.

Final update: May 8, 2009

Unique number: 48470
Classes: Tu Th 2:00 - 3:30 PM in Welch 3.502
Instructor: John Kormendy 
Office: RLM 15.326
Office Hours: Wednesday from 4 to 5:30 PM in RLM 15.326 or by appointment
Office Telephone: 471-8191
Email: kormendy@astro.as.utexas.edu
 
Teaching Assistant: Carlos Oliveira
Office: SZB 340
Office Hours: Tu Th from 12 Noon to 1:30 PM in SZB 340 (in the back of the room)
Telephone: (512) 772 - 4408
Email: carlos.oliveira@mail.utexas.edu
 
Teaching Assistant: Sehyun Hwang
Office: RLM 16.318
Office Hours: Monday from 3 to 5 PM and Friday from 10:30 AM to 12 Noon
Telephone: 471 - 3466
Email: shwang@astro.as.utexas.edu

Spring 2009 Syllabus

The final conversion from numerical to letter grade was as follows:

 A = 84.00 - 100.0 % (78 students)
 B = 73.50 - 83.99 % (71 students)
 C = 59.00 - 73.49 % (35 students)
 D = 44.00 - 58.99 % ( 9 students)
 CR = 44.00 - 100.0 % ( 1 student)
 F = less than 44 % ( 3 students)

I enjoyed teaching you more than any other class that I have taught. You were decisively the best class that I have had, either here in Texas or previously in Hawaii. There are far more As and Bs than the University expects when it says that B means "above average". Not counting the three F grades (I believe that those people were never in the class), 77 % of you got either an A or a B! The highest final grades were 94.8 % and 94.3 %, and 13 people got more than 90 %.

Maybe the most important thing that you can learn from this course is the importance of enthusiasm and hard work. You were enthusiastic and you worked hard -- that's why teaching this class was fun. You should be proud of your results. I am proud of you, and I wish you well in everything that you do.

Final grades were submitted at 9:25 PM on Friday, May 8, 2009.

John Kormendy's Home Page

University of Texas Astronomy Home Page

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John Kormendy (kormendy@astro.as.utexas.edu)