Performance of the near-infrared coronagraphic imager on Gemini-South

Chun, Mark; Toomey, Doug; Wahhaj, Z.; Biller, Beth; Artigau, Étienne; Hayward, Tom; Liu, Mike; Close, Laird M.; Hartung, Markus; Rigaut, François; Ftaclas, C.

doi:10.1117/12.787683

Cited by 40 publications

(23 citation statements)

References 7 publications

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“…Note. Column (2): the instrument used in each observation, including STIS, NICMOS, ACS, and WFPC2 on HST, CIAO (Tamura et al 2000) and HiCIAO on Subaru, NICI (Chun et al 2008) and GPI (Macintosh et al 2008) on Gemini, NACO (Lenzen et al 2003) and SPHERE (Beuzit et al 2008) on VLT, NIRC2 on Keck, and MagAO on Magellan (Morzinski et al 2014). Column (4): "pol"-polarized intensity; "total"-total intensity.…”

Section: Appendix a Scattered-light Disk Samplementioning

confidence: 99%

Spiral Arms in Disks: Planets or Gravitational Instability?

Dong

Najita

Brittain

2018

ApJ

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Spiral arm structures seen in scattered-light observations of protoplanetary disks can potentially serve as signposts of planetary companions. They can also lend unique insights into disk masses, which are critical in setting the mass budget for planet formation but are difficult to determine directly. A surprisingly high fraction of disks that have been well studied in scattered light have spiral arms of some kind (8/29), as do a high fraction (6/11) of wellstudied Herbig intermediate-mass stars (i.e., Herbig stars >1.5 M e ). Here we explore the origin of spiral arms in Herbig systems by studying their occurrence rates, disk properties, and stellar accretion rates. We find that two-arm spirals are more common in disks surrounding Herbig intermediate-mass stars than are directly imaged giant planet companions to mature A and B stars. If two-arm spirals are produced by such giant planets, this discrepancy suggests that giant planets are much fainter than predicted by hot-start models. In addition, the high stellar accretion rates of Herbig stars, if sustained over a reasonable fraction of their lifetimes, suggest that disk masses are much larger than inferred from their submillimeter continuum emission. As a result, gravitational instability is a possible explanation for multiarm spirals. Future observations can lend insights into the issues raised here.

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Section: Appendix a Scattered-light Disk Samplementioning

confidence: 99%

Spiral Arms in Disks: Planets or Gravitational Instability?

Dong

Najita

Brittain

2018

ApJ

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“…NaCo Ks (2.18 μm) and NICI (Chun et al 2008) H-band (1.65 μm) observations failed to reveal the planet (Rameau et al 2013a;Meshkat et al 2013). However, 5σ lower limits of Ks-L = 1.2 ± 0.5 mag and H − L = 3.1 ± 0.5 mag suggest that the planet may have extremely red colors, similar to the young planets HR 8799 bcde and 2M 1207 b (Chauvin et al 2004;Marois et al 2008Marois et al , 2010a, which have very dusty/cloudy atmospheres (Barman et al 2011;Currie et al 2011).…”

Section: Introductionmentioning

confidence: 93%

Near-infrared detection and characterization of the exoplanet HD 95086 b with the Gemini Planet Imager

Galicher¹,

Rameau²,

Bonnefoy³

et al. 2014

A&A

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HD 95086 is an intermediate-mass debris-disk-bearing star. VLT/NaCo 3.8 μm observations revealed it hosts a 5 ± 2 M Jup companion (HD 95086 b) at 56 AU. Follow-up observations at 1.66 and 2.18 μm yielded a null detection, suggesting extremely red colors for the planet and the need for deeper direct-imaging data. In this Letter, we report H-(1.7 μm) and K 1 -(2.05 μm) band detections of HD 95086 b from Gemini Planet Imager (GPI) commissioning observations taken by the GPI team. The planet position in both spectral channels is consistent with the NaCo measurements and we confirm it to be comoving. Our photometry yields colors of H − L = 3.6 ± 1.0 mag and K 1 − L = 2.4 ± 0.7 mag, consistent with previously reported 5-σ upper limits in H and Ks. The photometry of HD 95086 b best matches that of 2M 1207 b and HR 8799 cde. Comparing its spectral energy distribution with the BT-SETTL and LESIA planet atmospheric models yields T eff ∼ 600-1500 K and log g ∼ 2.1-4.5. Hot-start evolutionary models yield M = 5 ± 2 M Jup . Warm-start models reproduce the combined absolute fluxes of the object for M = 4-14 M Jup for a wide range of plausible initial conditions (S init = 8-13 k B /baryon). The color−magnitude diagram location of HD 95086 b and its estimated T eff and log g suggest that the planet is a peculiar L−T transition object with an enhanced amount of photospheric dust.

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“…NICI is a dedicated adaptive optics (AO) instrument tailored expressly for direct imaging of exoplanet companions (Chun et al 2008), combining several techniques to attenuate starlight and suppress speckles for direct detection of faint companions to bright stars: (1) Lyot coronagraphy, (2) dual-channel imaging for Spectral Differential Imaging (SDI; Racine et al 1999;Marois et al 2005;Biller et al 2007), and (3) operation in a fixed Cassegrain rotator mode for Angular Differential Imaging (ADI; Liu 2004; Marois et al 2006;Lafrenière et al 2007). As part of the NICI Planet-finding Campaign, HD 141569 was observed with NICI on 2009-03-07, 2010-04-08, and 2011-05-03.…”

Section: Observations and Data Reductionmentioning

confidence: 99%

The Gemini NICI Planet-Finding Campaign: asymmetries in the HD 141569 disc

Biller

Liu

Rice

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We report here the highest resolution near-IR imaging to date of the HD 141569A disc taken as part of the NICI (near-IR coronagraphic imager) Science Campaign. We recover 4 main features in the NICI images of the HD 141569 disc discovered in previous HST imaging: 1) an inner ring / spiral feature. Once deprojected, this feature does not appear circular. 2) an outer ring which is considerably brighter on the western side compared to the eastern side, but looks fairly circular in the deprojected image.3) an additional arc-like feature between the inner and outer ring only evident on the east side. In the deprojected image, this feature appears to complete the circle of the west side inner ring and 4) an evacuated cavity from 175 AU inwards. Compared to the previous HST imaging with relatively large coronagraphic inner working angles (IWA), the NICI coronagraph allows imaging down to an IWA of 0.3". Thus, the inner edge of the inner ring/spiral feature is well resolved and we do not find any additional disc structures within 175 AU. We note some additional asymmetries in this system. Specifically, while the outer ring structure looks circular in this deprojection, the inner bright ring looks rather elliptical. This suggests that a single deprojection angle is not appropriate for this system and that there may be an offset in inclination between the two ring / spiral features. We find an offset of 4±2 AU between the inner ring and the star center, potentially pointing to unseen inner companions.

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Performance of the near-infrared coronagraphic imager on Gemini-South

Cited by 40 publications

References 7 publications

Spiral Arms in Disks: Planets or Gravitational Instability?

Spiral Arms in Disks: Planets or Gravitational Instability?

Near-infrared detection and characterization of the exoplanet HD 95086 b with the Gemini Planet Imager

The Gemini NICI Planet-Finding Campaign: asymmetries in the HD 141569 disc

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