•In order to collect a sample from an asteroid, it is necessary to be able to track it and determine it’s rotation period.

•One way to do this is differential photometry, a method in which images of an asteroid are taken and then analyzed.

•By monitoring the variation in brightness of the asteroid compared to comparison stars the rotation period can be determined.

1) NEODys database. http://newton.dm.unipi.it/cgi-bin/neodys/neoibo

2) ASTDys database. http://hamilton.dm.unipi.it/cgi-bin/astdys/astibo

Project Description

• We will locate a NEO that is:

1. in the correct RA range such that it will transit near the middle of the night. (RA range 11 hours to 23 hours for the summer.)

2. Bright enough to observe using the NFO telescope (brighter than magnitude 15).

• W will obtain images hourly to determine the rotation period of the NEO. The images will be measured using the program NFO measure.

• Dr. Lacy will modify his program NFO NEOs to automatically track and measure any asteroid as it moves. We will compare the observed positions of the asteroid with the predictions from the NEODys and ASTDys databases and see if the orbital elements can be improved.

The NFO Telescope

The Arkansas Center for Space and Planetary Sciences REU is funded by

NASA.

References and Acknowledgments

•We hope to modify Dr. Lacy’s program such that it will be able to track and measure any asteroid as it moves.

•We also hope to improve upon the data regarding the orbital elements of the NEO.

Background

Using the NEODys and ASTDys websites, we have selected the asteroid 433 Eros for study.

433 Eros

•Right Ascension: 13.17 hours

•Declination: -27.70 degrees

•Solar Elongation: 116.65 degrees

•V Magnitude: 12.21

We are considering another asteroid, 2001 LF, for study as well. Once we have obtained images of Eros, we will be able to determine if 2001 LF is too faint to observe using the NFO telescope.

Current Progress Future Work

Rozmin Daya1, 2, Claud Lacy1, 3

1. Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR 727012. Physics Department, Southern Methodist University, Dallas, TX 752753. Physics Department, University of Arkansas, Fayetteville, AR 72701

The NFO telescope uses a 24 inch Cassegrain reflector with a 2K by 2K CCD camera on the back end. Observations will be made using the telescope’s R filter.

Near Earth Objects

2001 LF

•Right Ascension: 17.08 hours

•Declination: -23.33 degrees

•Solar Elongation: 168.69 degrees

•V Magnitude: 14.87

For both asteroids, RA and Declination are as of 06-21-2005 (UT).

•Extrasolar planets can be detected when they transit their parent star blocking a percentage of its light.

•This can give information about: the planet’s orbital period, radius, mass, density, and distance from it’s parent star.

1) Alonso et al., Astrophysical Journal Letters, 613, L153

2) Brown, T. M., Charbonneau, D., Gilliland, R. L., Noyes, R. W., & Burrows, A. 2001, Astrophysical Journal, 552, 699

Project Description

•Transits of the planets HD 209458b and TrES-1b will be photographed using the NFO telescope in Silver City, New Mexico.

•These images will be measured using the program Measure.

•Light curves for the stars will be constructed.

•The light curves will be analyzed using the program EBOP, which uses the Nelson-Davis-Etzel model code.

•Orbital data for the planets will be obtained from these curves. We will try to improve on the orbital data from previous observations.

The NFO Telescope

The Arkansas Center for Space and Planetary Sciences REU is funded by

NASA.

References and Acknowledgments

Currently we are using the telescope to obtain images of the transits. As we get the images, we measure them. Once all data is collected we will continue with the remaining steps of the project.

Background

Below and to the left are the light curves for TrES-1. The curves were constructed using images from various telescopes in the Trans-Atlantic Exoplanet Survey (TrES) network. Below and to the right is the orbital data for TrES-1b.1

Data and Graphs Current Progress

Below is the light curve for HD209458. This is the “phased light curve for all four transits, assuming a planetary orbital period of 3.52474 days. The time series for each transit has been scaled to have the same

average intensity over the second and fifth (out-of-transit) orbits.”2 (Images were obtained using the Hubble Space Telescope.)

“Schematic illustration of the light curve of a transiting planet. Measurable quantities: duration of the transit l, the transit depth d, the ingress/egress duration w, and the central curvature of the light curve C. “2

Rozmin Daya1, 2, Claud Lacy1, 3

1. Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR 727012. Physics Department, Southern Methodist University, Dallas, TX 752753. Physics Department, University of Arkansas, Fayetteville, AR 72701

Transiting Extrasolar Planets Orbiting HD 209458 and TrES-1

The NFO telescope uses a 24 inch Cassegrain reflector with a 2K by 2K CCD camera on the back end. For HD 209458, observations are being made using B, V, and R filters; for TrES-1, observations are being made using the R filter.