THE TRANSIT INGRESS AND THE TILTED ORBIT OF THE EXTRAORDINARILY ECCENTRIC EXOPLANET HD 80606b

Journal Article · Thu Oct 01 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/2/2091· OSTI ID:21371844

Winn, Joshua N ^[1]; Howard, Andrew W; Marcy, Geoffrey W ^[2]; Johnson, John Asher; Gazak, J Zachary ^[3]; Starkey, Donn ^[4]; Ford, Eric B; Colon, Knicole D; Reyes, Francisco ^[5]; Nortmann, Lisa; Dreizler, Stefan ^[6]; Odewahn, Stephen ^[7]; Welsh, William F; Kadakia, Shimonee ^[8]; Vanderbei, Robert J ^[9]; Adams, Elisabeth R; Lockhart, Matthew ^[10]; Crossfield, Ian J ^[11]; Valenti, Jeff A ^[12]; Dantowitz, Ronald ^[13]

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1. Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
2. Department of Astronomy, University of California, Mail Code 3411, Berkeley, CA 94720 (United States)
3. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
4. DeKalb Observatory H63, Auburn, IN 46706 (United States)
5. Department of Astronomy, University of Florida, 211 Bryant Space Center, P.O. Box 112055, Gainesville, FL 32611 (United States)
6. Institute for Astrophysics, Friedrich-Hund-Platz 1, D-37077 Goettingen (Germany)
7. McDonald Observatory, University of Texas, Austin, TX 78712 (United States)
8. Department of Astronomy, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States)
9. Department of Operations Research and Financial Engineering, Princeton University, Princeton, NJ 08544 (United States)
10. Department of Earth, Atmospheric, and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
11. Department of Astronomy, University of California, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095 (United States)
12. Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)
13. Clay Center Observatory, Dexter and Southfield Schools, 20 Newton St., Brookline, MA 02445 (United States)

We present the results of a transcontinental campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 +- 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle lambda is between 32 deg. and 87 deg. with 68.3% confidence and between 14 deg. and 142 deg. with 99.73% confidence. Thus, the orbit of this planet is not only highly eccentric (e = 0.93) but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is worth noting that all three exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting that those systems migrate through a different channel than lower mass planets on circular orbits.

• OSTI ID: 21371844
• Journal Information: Astrophysical Journal, Vol. 703, Issue 2; Other Information: DOI: 10.1088/0004-637X/703/2/2091; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DETECTION
MASS
ORBITS
PLANETS
ROTATION
SPIN
STARS
ANGULAR MOMENTUM
MOTION
PARTICLE PROPERTIES