First light of the VLT planet finder SPHERE - III. New spectrophotometry and astrometry of the HR 8799 exoplanetary system

By A. Zurlo, A. Vigan, R. Galicher, A. Maire, D. Mesa, R. Gratton, G. Chauvin, M. Kasper, C. Moutou, M. Bonnefoy and 63 more. 2015

141 citations recorded by the source corpus.

Context. The planetary system discovered around the young A-type HR 8799 provides a unique laboratory to: a) test planet formation theories; b) probe the diversity of system architectures at these separations, and c) perform comparative (exo)planetology. Aims. We present and exploit new near-infrared images and integral-field spectra of the four gas giants surrounding HR 8799 obtained with SPHERE, the new planet finder instrument at the Very Large Telescope, during the commissioning and science verification phase of the instrument (July–December 2014). With these new data, we contribute to completing the spectral energy distribution (SED) of these bodies in the 1.0–2.5 μm range. We also provide new astrometric data, in particular for planet e, to further constrain the orbits. Methods. We used the infrared dual-band imager and spectrograph (IRDIS) subsystem to obtain pupil-stabilized, dual-band H2H3 (1.593 μm, 1.667 μm), K1K2 (2.110 μm, 2.251 μm), and broadband J (1.245 μm) images of the four planets. IRDIS was operated in parallel with the integral field spectrograph (IFS) of SPHERE to collect low-resolution (R ~ 30), near-infrared (0.94–1.64 μm) spectra of the two innermost planets HR 8799 d and e. The data were reduced with dedicated algorithms, such as the Karhunen-Loeve image projection (KLIP), to reveal the planets. We used the so-called negative planets injection technique to extract their photometry, spectra, and measure their positions. We illustrate the astrometric performance of SPHERE through sample orbital fits compatible with SPHERE and literature data. Results. We demonstrated the ability of SPHERE to detect and characterize planets in this kind of systems, providing spectra and photometry of its components. The spectra improve upon the signal-to-noise ratio of previously obtained data and increase the spectral coverage down to the Y band. In addition, we provide the first detection of planet e in the J band. Astrometric positions for planets HR 8799 bcde are reported for the epochs of July, August, and December 2014. We measured the photometric values in J, H2H3, K1K2 bands for the four planets with a mean accuracy of 0.13 mag. We found upper limit constraints on the mass of a possible planet f of 3–7 MJup . Our new measurements are more consistent with the two inner planets d and e being in a 2d:1e or 3d:2e resonance. The spectra of HR 8799 d and e are well matched by those of L6-8 field dwarfs. However, the SEDs of these objects are redder than field L dwarfs longward of 1.6 μm.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/5c6f9a83ba95666b530a35b7a538de2870998f9a

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In Astronomy and Astrophysics

1. Th. Henning
2. C. Mordasini
3. B. Bowler
4. S. Udry
5. Paul Mollière
6. R. Gratton
7. Anne-Marie Lagrange
8. C. Moutou

In Instrumentation

1. R. Gratton
2. C. Mordasini
3. Th. Henning
4. V. D’Orazi
5. C. Moutou
6. Anthony Boccaletti
7. G. Chauvin
8. S. Udry

Citations in the corpus

• Discovery of a warm, dusty giant planet around HIP 65426 (2017, background): “…compiled from the literature (Burgasser 2014; Best et al. 2015; Mace et al. 2013; Allers & Liu 2013) as well as spectra of young imaged exoplanets and brown dwarfs close to the L/T transition (Patience et al. 2010; Zurlo et al. 2016; De Rosa et al. 2014; Artigau et al. 2015; Gauza et al. 2015).”
• Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e (2020, methodology): “For comparison, the S/N per wavelength step of HR 8799e is about 4 (λ/∆λ ≈ 70), 7 (λ/∆λ ≈ 200), and 11 (λ/∆λ ≈ 1000) for the SPHERE YJH (Zurlo et al. 2016), GPI H (Greenbaum et al. 2018) and GRAVITY K (Gravity Collaboration 2019) band data, respectively.”
• SPHERE: the exoplanet imager for the Very Large Telescope (2019, methodology): “…of IRDIS DBI on its own have been demonstrated in Vigan et al. (2016a), but it becomes most efficient when combined with the IFS for companions in the central part of the SPHERE FoV (e.g., Zurlo et al. 2016; Samland et al. 2017; Delorme et al. 2017; Mesa et al. 2018; Cheetham et al. 2018).”
• Imaging Extrasolar Giant Planets (2016, unknown): “Initial results from the SHINE survey include observations of the brown dwarf GJ 758 B (Vigan et al. 2016), PZ Tel B and HD 1160 B (Maire et al. 2016), HD 106906 (Lagrange et al. 2016), and the HR 8799 planets (Zurlo et al. 2016; Bonnefoy et al. 2016).”