interferometry at altitude : galaxies, stars, and exoplanets
DESCRIPTION
Interferometry at Altitude : Galaxies, Stars, and Exoplanets. BETTII, BENI, and Other Fantastical Notions. With contributions from R. Lyon (BENI PI), the BENI team , and the BETTII team. Motivation. Angular Resolution! Contrast (nulling). Design. How Does it Work?. - PowerPoint PPT PresentationTRANSCRIPT
S. RinehartNASA’s GSFC
Interferometry at Altitude: Galaxies, Stars, and Exoplanets
BETTII, BENI, and Other Fantastical Notions
With contributions from R. Lyon (BENI PI), the BENI team, and the
BETTII team
October 27, 2009
S. RinehartInterferometry at Altitude 2
Motivation
• Angular Resolution!
• Contrast (nulling)
October 27, 2009
S. RinehartInterferometry at Altitude 3
Design
October 27, 2009
S. RinehartInterferometry at Altitude 4
How Does it Work?
• Observe at different times to get sky rotation
• Enables accurate derivation of relative positions
• Effective resolution of ~0.5 arcsec
• By stroking the delay line, we obtain fringe packets
• Can derive the spectrum of the sources from the fringes
Spatially-Resolved Spectroscopy
October 27, 2009
S. RinehartInterferometry at Altitude 5
BETTII Science I
Star formation:
•Does star formation in clusters differ from that in isolated regions?
• What FIR emission arises from disks of individual sources? From inner envelopes?
October 27, 2009
S. RinehartInterferometry at Altitude 6
BETTII Science II
Active Galactic Nuclei:
• What are the energetics in the core of an AGN?
• How do different regions contribute to the FIR flux?
October 27, 2009
S. RinehartInterferometry at Altitude 7
What is BENI?
•Fizeau interferometry
o 3 10-cm collectors
o 1.5 meter baselineo Visible Nulling Interferometer
• Technologically challenging
o Reactionless payload tracking
o Fine pointing with 3 FSMso Active wavefront control
The VNC Testbed: BENI on a Bench
October 27, 2009
S. RinehartInterferometry at Altitude 8
Visible Nulling
• Mach-Zehnder Interferometer
• Light split at first beamsplitter
• Recombined at second
• Combine beams from 3 telescopes (Fizeau)
• Arm #1: Catseye reflector (flips image and rotates polarization 180°)
• Arm #2; deformable mirror (feedback from bright output)
October 27, 2009
S. RinehartInterferometry at Altitude 9
BENI Science I
Exoplanets
Directly image a Jovian planet
Image a debris disk
• Exozodiacal Light
• Hidden planets?
October 27, 2009
S. RinehartInterferometry at Altitude 10
BENI Science II
Characterize the high altitude atmosphere
• Turbulence
• Scintillation
• Greenwood frequency
Estimates made via modeling now indicate:
• Turbulence: ro > 50m
• Scintillation < 0.1%
• fG << 1 Hz
October 27, 2009
S. RinehartInterferometry at Altitude 11
Follow-onThere’s great science with BETTII, and her daughters (longer booms, cold telescopes, nulling, moveable siderostats…..) will be able to do even more!
The same is true for BENI; could we do spectroscopy of exoplanets on a balloon?Both also pave the way for potential space missions…
October 27, 2009
S. RinehartInterferometry at Altitude 12
Thanks
The BETTII Team:S. Rinehart1 (PI), C. Allen1, R. Barry1, D. Benford, W. Danchi1, D. Fixsen2, D.
Leisawitz1, L. Mundy2, R. Silverberg1, J. Staguhn2, A. Kogut1, R. Lyon1, J. Mather1
The BENI Team:R. Lyon1, M. Clampin1, J. Herman1, S. Rinehart1, K. Carpenter1, H. Ford3, L.
Petro4, G. Vasudevan5, R. Woodruff5, J. Marzouk6,
P. Petrone6
1: GSFC 2: UMCP 3: JHU 4: STScI 5: Lockheed-Martin 6: Sigma Space