Astrophotonics & the CHARA Array

Nic Scott

telescope system scientist - the CHARA Array

Jul 2024

diameter

Lawson 2003, S&T

Science Drivers

• multiple star systems
• stellar diameters
• YSOs/planetary formation
• evolved stars
• starspots/surface imaging
• exozodis
• AGN
• exoplanet hosts

The Gaia orbits give the center-of-light motion of unresolved binaries, and a single resolved CHARA observation is sufficient to determine the full orbit and masses.

High angular resolution observations also reveal how interacting stars are transformed by mass exchange.

Ashley Elliott 2024

Diameters of Stars

Ashley Elliott (LSU) has compiled interferometric measurements from CHARA and more to create an empirical HR diagram.

Angular Dia. + Parallax  → Linear Radius

Diameter + Bolometric Flux → Teff

SCIENTIFIC RESULTS

693 stars, σθ < 5%

Torres et al. 2022

Torres et al. 2024

Binary & Multiples

Castor A and B

• resolved the inner binary components
• masses and 3D orbits
• mutual orientations of the different components.

HD 284163

hierarchical quadruple system

• orbits of the inner (2.39 d) and first outer (43.1 yr) are    nearly orthogonal
• Accurate masses including that of the secondary
• (0.5245 ± 0.0047 M⊙) is now the lowest mass star with a dynamical mass measurement in the Hyades cluster.

ARMADA astrometry survey to search for triple systems among known intermediate mass binaries.  

•  ~ 20 - 50 μas residuals
• potentially could detect Jupiter-mass exoplanets in binaries.

Gardner et al. 2021

Roettenbacher et al. 2016, Nature, 533, 217

Spotted magnetic stars

Regulus -- Che et al. 2011, ApJ, 732, 68

Rasalhague -- Zhao et al. 2009, ApJ, 701, 209

Altair -- Monnier et al. 2007, Science, 317, 324

Alderamin -- Zhao et al. 2009, ApJ, 701, 209

Beta Cas -- Che et al. 2011, ApJ, 732, 68

Roettenbacher et al. 2017

Martinez et al. (2021)

Rapid Rotators

Zet And

Sig Gem

Lam And

θ = 2.7 mas

θ = 2.5 mas

θ = 2.4 mas

Resolved stellar surfaces

Kloppenborg et al. 2010, Nature, 464, 870

Schaefer et al. 2014, Nature, 515, 234

Expansion curve of Nova Del 2013.

• Changes in apparent expansion – optically thick core surrounded by diffuse envelope that cools over time
• Geometric disk: 4.5 kpc
• Asymmetric shape detected as early as 2d

Image Reconstruction of AZ Cyg
Norris et al. (2021)

Model Simulation
Chiavassa et al. (2010)

P = 12.9 d
a = 0.87 mas

Zhao et al. 2008, ApJ, 684, 95

Be stars

Gies, D. R., et al. 2007, ApJ, 654, 527

Mourard, D., et al. 2015, A&A, 577, 51

Schaefer, G. H., et al. 2010, AJ, 140, 1838

Touhami, Y., et al. 2013, ApJ, 768, 128

Giant star surfaces

Imaging Luminous Stars

The cool hypergiant star RW Cep experienced a Great Dimming event in 2022:

• imaged near photometric minimum
• H & K-band images show an asymmetric intensity distribution and a distorted shape
• NIR spectroscopy found fading increased towards shorter wavelengths
• implicates dust formation from stellar ejecta as the explanation for the fading and unusual appearance.  

Anugu et al. 2023

Patchy appearance results from dust created by a huge ejection from the star

Illustration credit: NASA, ESA, and E. Wheatley (STScI)

Anugu and colleagues are continuing to monitor the star with CHARA to explore how the surface appearance changes as the star brightens again.  

Disks Around Young Stars

The disks around T Tau type and other Young Stellar Objects (YSOs) are the birthplaces of planets, and interferometric imaging offers important clues about the environments surrounding planet formation.

Labdon et al. 2023

SU Aur

MIRC-X observations of  to build a model of the circumstellar disk's geometric and physical properties.  

• inclined and warped
• flux mainly comes from the illuminated far side of the disk
• near side partially obscures the central star
• dust emission indicate formation of a disk wind from the upper and lower boundaries of the warped disk.

luminous Herbig Be star HD 190073

•  YSO disk is viewed almost face-on (i<20°)
• clear view of the full extent of the inner gas disk.
• discovered a bright spot in the disk that migrated by 27° over of 32 days  

Ibrahim et al. 2023

Future: Image an exoplanet during transit

There are some 250 known exoplanets with host stars accessible to CHARA.

The new baselines will enable resolution of solar-like stars out to about 70pc in H-band.

Numerical simulations of the transiting hot-Jupiter in HD189773 indicate that the shape of the silhouette of the planet can be measured in long baseline observations made during transits.

NGC 4151

Active Galactic Nuclei

bright central region of the active galactic nucleus of the Seyfert galaxy NGC 4151.  

• Central structure resolved at the 0.5 mas scale.
• ring-like structure viewed at an inclination of 40°
• perpendicular to the radio jet
• K-band flux probably originates in a dust sublimation region on the face of the torus surrounding the black hole.

[1] Eisenhauer, F., Monnier, J. D., and Pfuhl, O., “Advances in Optical/Infrared Interferometry,” 61, 237–285 (Aug. 2023).

[2] Ridgway, S. and Schaefer, G., “The NOIRLab/CHARA Connection Marks Decadal Milestones Up to 40 Years,” The NOIRLab Mirror 5, 36 (Aug. 2023).

[3] Gies, D. R., Anderson, M. D., Anugu, N., ten Brummelaar, T. A., Castillo, V., Farrington, C. D., Golden, S., Jones, J. W., Klement, R., K ̈ohler, R., Lanthermann, C., Ligon, E. R., Majoinen, O., McAlister, H. A., Ridgway, S. T., Schaefer, G. H., Scott, N. J., Turner, N. H., Vargas, N. L., Webster, L., and Woods, C., “Recent technical and scientific highlights from the CHARA Array,” in [Optical and Infrared Interferometry and Imaging VIII ], M ́erand, A., Sallum, S., and Sanchez-Bermudez, J., eds., Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series 12183, 1218303 (Aug. 2022).

[4] Yu, J., Khanna, S., Themessl, N., Hekker, S., Dr ́eau, G., Gizon, L., and Bi, S., “Revised Extinctions and Radii for 1.5 Million Stars Observed by APOGEE, GALAH, and RAVE,” 264, 41 (Feb. 2023).

[5] Korolik, M., Roettenbacher, R. M., Fischer, D. A., Kane, S. R., Perkins, J. M., Monnier, J. D., Davies, C. L., Kraus, S., Le Bouquin, J.-B., Anugu, N., Gardner, T., Lanthermann, C., Schaefer, G. H., Setterholm, B., Brewer, J. M., Llama, J., Zhao, L. L., Szymkowiak, A. E., and Henry, G. W., “Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog,” 166, 123 (Sept. 2023).

[6] Konstantinova-Antova, R., Georgiev, S., L`ebre, A., Palacios, A., Morin, J., Bogdanovski, R., Abbott, C., Baron, F., Auri`ere, M., Drake, N. A., Tsvetkova, S., Josselin, E., Paladini, C., Mathias, P., and Zamanov, R., “A long-term study of the magnetic field and activity in the M giant RZ Ari. Magnetism and planet engulfment in a fairly evolved star?,” 681, A36 (Jan. 2024).

[7] Caballero, J. A., Gonz ́alez- ́Alvarez, E., Brady, M., Trifonov, T., Ellis, T. G., Dorn, C., Cifuentes, C., Molaverdikhani, K., Bean, J. L., Boyajian, T., Rodr ́ıguez, E., Sanz-Forcada, J., Zapatero Osorio, M. R., Abia, C., Amado, P. J., Anugu, N., B ́ejar, V. J. S., Davies, C. L., Dreizler, S., Dubois, F., Ennis, J., Espinoza, N., Farrington, C. D., L ́opez, A. G., Gardner, T., Hatzes, A. P., Henning, T., Herrero, E.,
Herrero-Cisneros, E., Kaminski, A., Kasper, D., Klement, R., Kraus, S., Labdon, A., Lanthermann, C., Le Bouquin, J. B., L ́opez Gonz ́alez, M. J., Luque, R., Mann, A. W., Marfil, E., Monnier, J. D., Montes, D., Morales, J. C., Pall ́e, E., Pedraz, S., Quirrenbach, A., Reffert, S., Reiners, A., Ribas, I., Rodr ́ıguez-L ́opez, C., Schaefer, G., Schweitzer, A., Seifahrt, A., Setterholm, B. R., Shan, Y., Shulyak, D., Solano, E., Sreenivas, K. R., Stef ́ansson, G., St ̈urmer, J., Tabernero, H. M., Tal-Or, L., ten Brummelaar, T., Vanaverbeke, S., von Braun, K., Youngblood, A., and Zechmeister, M., “A detailed analysis of the Gl 486 planetary system,” 665, A120 (Sept. 2022).

[8] Martin, R. G., Lubow, S. H., Vallet, D., Anugu, N., and Gies, D. R., “AC Her: Evidence of the First Polar Circumbinary Planet,” 957, L28 (Nov. 2023).

[9] Stuber, T. A., Kirchschlager, F., Pearce, T. D., Ertel, S., Krivov, A. V., and Wolf, S., “How much large dust could be present in hot exozodiacal dust systems?,” 678, A121 (Oct. 2023).

[10] Anugu, N., Baron, F., Gies, D. R., Lanthermann, C., Schaefer, G. H., Shepard, K. A., Brummelaar, T. t., Monnier, J. D., Kraus, S., Le Bouquin, J.-B., Davies, C. L., Ennis, J., Gardner, T., Labdon, A., Roettenbacher, R. M., Setterholm, B. R., Vollmann, W., and Sigismondi, C., “The Great Dimming of the Hypergiant Star RW Cephei: CHARA Array Images and Spectral Analysis,” 166, 78 (Aug. 2023).

[11] Labdon, A., Kraus, S., Davies, C. L., Kreplin, A., Zarrilli, S., Monnier, J. D., Le Bouquin, J.-B., Anugu, N., Setterholm, B., Gardner, T., Ennis, J., Lanthermann, C., ten Brummelaar, T., Schaefer, G., and Harries, T. J., “Imaging the warped dusty disk wind environment of SU Aurigae with MIRC-X,” 678, A6 (Oct. 2023).

[12] Ibrahim, N., Monnier, J. D., Kraus, S., Le Bouquin, J.-B., Anugu, N., Baron, F., Brummelaar, T. T., Davies, C. L., Ennis, J., Gardner, T., Labdon, A., Lanthermann, C., M ́erand, A., Rich, E., Schaefer, G. H., and Setterholm, B. R., “Imaging the Inner Astronomical Unit of the Herbig Be Star HD 190073,” 947, 68 (Apr. 2023).

[13] Bourdarot, G., Berger, J. P., Lesur, G., Perraut, K., Malbet, F., Millan-Gabet, R., Le Bouquin, J. B., Garcia-Lopez, R., Monnier, J. D., Labdon, A., Kraus, S., Labadie, L., and Aarnio, A., “FU Orionis disk outburst: Evidence for a gravitational instability scenario triggered in a magnetically dead zone,” 676, A124 (Aug. 2023).

[14] Zarrilli, S. A., Kraus, S., Kreplin, A., Monnier, J. D., Gardner, T., M ́erand, A., Morrell, S., Davies, C. L., Labdon, A., Ennis, J., Setterholm, B., Le Bouquin, J.-B., Anugu, N., Lanthermann, C., Schaefer, G., and ten Brummelaar, T., “Characterising the orbit and circumstellar environment of the high-mass binary MWC 166 A,” 665, A146 (Sept. 2022).

[15] Lanthermann, C., Le Bouquin, J. B., Sana, H., M ́erand, A., Monnier, J. D., Perraut, K., Frost, A. J., Mahy, L., Gosset, E., De Becker, M., Kraus, S., Anugu, N., Davies, C. L., Ennis, J., Gardner, T., Labdon, A., Setterholm, B., ten Brummelaar, T., and Schaefer, G. H., “Multiplicity of northern bright O-type stars with optical long baseline interferometry. Results of the pilot survey,” 672, A6 (Apr. 2023).

[16] De Furio, M., Gardner, T., Monnier, J., Meyer, M. R., Kratter, K., Schaefer, G., Anugu, N., Davies, C. L., Kraus, S., Lanthermann, C., Le Bouquin, J.-B., and Ennis, J., “The Small Separation A-star Companion Population: First Results with CHARA/MIRC-X,” 941, 118 (Dec. 2022).

[17] Torres, G., Schaefer, G. H., Monnier, J. D., Anugu, N., Davies, C. L., Ennis, J., Farrington, C. D., Gardner, T., Klement, R., Kraus, S., Labdon, A., Lanthermann, C., Le Bouquin, J.-B., Setterholm, B. R., and ten Brummelaar, T., “The Orbits and Dynamical Masses of the Castor System,” 941, 8 (Dec. 2022).

[18] Torres, G., Schaefer, G. H., Stefanik, R. P., Latham, D. W., Jones, J., Lanthermann, C., Monnier, J. D., Kraus, S., Anugu, N., ten Brummelaar, T., Chhabra, S., Codron, I., Ennis, J., Gardner, T., Gutierrez, M., Ibrahim, N., Labdon, A., Mortimer, D., and Setterholm, B. R., “Orbits and dynamical masses for the active Hyades multiple system HD 284163,” 527, 8907–8920 (Jan. 2024).

[19] Gardner, T., Monnier, J. D., Fekel, F. C., Le Bouquin, J.-B., Scovera, A., Schaefer, G., Kraus, S., Adams, F. C., Anugu, N., Berger, J.-P., Ten Brummelaar, T., Davies, C. L., Ennis, J., Gies, D. R., Johnson, K. J. C., Kervella, P., Kratter, K. M., Labdon, A., Lanthermann, C., Sahlmann, J., and Setterholm, B. R., “ARMADA. II. Further Detections of Inner Companions to Intermediate-mass Binaries with Microarcsecond Astrometry at CHARA and VLTI,” 164, 184 (Nov. 2022).

[20] Lam, R., Sandquist, E. L., Schaefer, G. H., Farrington, C. D., Monnier, J. D., Anugu, N., Lanthermann, C., Klement, R., Ennis, J., Setterholm, B. R., Gardner, T., Kraus, S., Davies, C. L., and Orosz, J. A., “Precise Age for the Binary Star System 12 Com in the Coma Berenices Cluster,” 166, 29 (July 2023).

[21] Morales, L. M., Sandquist, E. L., Schaefer, G. H., Farrington, C. D., Klement, R., Bedin, L. R., Libralato, M., Malavolta, L., Nardiello, D., Orosz, J. A., Monnier, J. D., Kraus, S., Le Bouquin, J.-B., Anugu, N., ten Brummelaar, T., Davies, C. L., Ennis, J., Gardner, T., and Lanthermann, C., “The Interferometric Binary Cnc in Praesepe: Precise Masses and Age,” 164, 34 (Aug. 2022).

[22] Lester, K. V., Schaefer, G. H., Fekel, F. C., Gies, D. R., Henry, T. J., Jao, W.-C., Paredes, L. A., Hubbard-James, H.-S., Farrington, C. D., Gordon, K. D., Chojnowski, S. D., Monnier, J. D., Kraus, S., Bouquin, J.-B. L., Anugu, N., ten Brummelaar, T., Davies, C. L., Gardner, T., Labdon, A., Lanthermann, C., and Setterholm, B. R., “Visual Orbits of Spectroscopic Binaries with the CHARA Array. IV. HD 61859, HD 89822, HD 109510, and HD 191692,” 164, 228 (Dec. 2022).

[23] Klement, R., Schaefer, G. H., Gies, D. R., Wang, L., Baade, D., Rivinius, T., Gallenne, A., Carciofi, A. C., Monnier, J. D., M ́erand, A., Anugu, N., Kraus, S., Davies, C. L., Lanthermann, C., Gardner, T., Wysocki, P., Ennis, J., Labdon, A., Setterholm, B. R., and Le Bouquin, J.-B., “Interferometric Detections of sdO Companions Orbiting Three Classical Be Stars,” 926, 213 (Feb. 2022).

[24] Klement, R., Baade, D., Rivinius, T., Gies, D. R., Wang, L., Labadie-Bartz, J., Ticiani dos Santos, P., Monnier, J. D., Carciofi, A. C., M ́erand, A., Anugu, N., Schaefer, G. H., Le Bouquin, J.-B., Davies, C. L., Ennis, J., Gardner, T., Kraus, S., Setterholm, B. R., and Labdon, A., “Dynamical Masses of the Primary Be Star and Secondary sdB Star in the Single-lined Binary κ Dra (B6 IIIe),” 940, 86 (Nov. 2022).

[25] Klement, R., Rivinius, T., Gies, D. R., Baade, D., M ́erand, A., Monnier, J. D., Schaefer, G. H., Lanthermann, C., Anugu, N., Kraus, S., and Gardner, T., “The CHARA Array Interferometric Program on the Multiplicity of Classical Be Stars: New Detections and Orbits of Stripped Subdwarf Companions,” 962, 70 (Feb. 2024).

[26] Wang, L., Gies, D. R., Peters, G. J., G ̈otberg, Y., Chojnowski, S. D., Lester, K. V., and Howell, S. B., “The Detection and Characterization of Be+sdO Binaries from HST/STIS FUV Spectroscopy,” 161, 248 (May 2021).

[27] Gies, D. R., Wang, L., and Klement, R., “Gamma Cas Stars as Be+White Dwarf Binary Systems,” 942, L6 (Jan. 2023).

[28] Kishimoto, M., Anderson, M., ten Brummelaar, T., Farrington, C., Antonucci, R., H ̈onig, S., Millour, F., Tristram, K. R. W., Weigelt, G., Sturmann, L., Sturmann, J., Schaefer, G., and Scott, N., “The Dust Sublimation Region of the Type 1 AGN NGC 4151 at a Hundred Microarcsecond Scale as Resolved by the CHARA Array Interferometer,” 940, 28 (Nov. 2022).

[29] Setterholm, B. R., Monnier, J. D., Le Bouquin, J.-B., Anugu, N., Ennis, J., Jocou, L., Ibrahim, N., Kraus, S., Anderson, M. D., Chhabra, S., Codron, I., Farrington, C. D., Flores, B., Gardner, T., Gutierrez, M., Lanthermann, C., Majoinen, O. W., Mortimer, D. J., Schaefer, G., Scott, N. J., ten Brummelaar, T., and Vargas, N. L., “MYSTIC: a high angular resolution K-band imager at CHARA,” Journal of Astronomical Telescopes, Instruments, and Systems 9, 025006 (Apr. 2023)

References

Charting Quantum Horizons March 2024 - Tucson, AZ

• Review of the current state of capabilities and techniques in optical/IR interferometry
  • Highlight science cases enabled by microarcsecond resolution at optical/IR wavelengths (e.g. exoplanets, stellar physics, young stars/disks, AGN and SMBHs)
• Discuss quantum-enhanced methods for pushing current limitations on spatial resolution
• Establish collaborations between the astronomy and quantum communities to address science requirements and technical challenges

• special session of the annual CHARA meeting
• upcoming optical interferometry workshop (in planning)
• next CHARA meeting: Nice, France (May 2025)

The full Michelson Array would offer

12 total positions, creating 66 possible baselines.

Lanthermann et al. 2022

SILMARIL

Aug 2023 - First fringes

NOAO open access time

• 352 proposals submitted since 2010
• 101 unique OA PIs from 73 distinct institutions

• dedicated to community growth in US and beyond