Accretion Properties of PDS 70b with MUSE*

Hashimoto, Jun; Aoyama, Yuhiko; Konishi, Mihoko; Uyama, Taichi; Takasao, Shinsuke; Ikoma, Masahiro; Tanigawa, Takayuki

doi:10.3847/1538-3881/ab811e

Cited by 58 publications

(122 citation statements)

References 48 publications

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“…If we assume a moderate accretion rate of 10 −8 M yr −1 as in Zhu (2015), it translates into a planet mass of 4 − 13M J . We note that the accretion rates estimated for PDS 70b are orders of magnitude lower (Haffert et al 2019;Hashimoto et al 2020), which then would imply stellar mass for f1. As a consequence, the flux of f1 is likely not to be dominated by thermal emission.…”

Section: Discussionmentioning

confidence: 78%

Possible evidence of ongoing planet formation in AB Aurigae

Boccaletti

Folco

Pantin

et al. 2020

A&A

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Context. Planet formation is expected to take place in the first million years of a planetary system through various processes, which remain to be tested through observations. Aims. With the recent discovery, using ALMA, of two gaseous spiral arms inside the ∼120 au cavity and connected to dusty spirals, the famous protoplanetary disk around AB Aurigae presents a strong incentive for investigating the mechanisms that lead to giant planet formation. A candidate protoplanet located inside a spiral arm has already been claimed in an earlier study based on the same ALMA data. Methods. We used SPHERE at the Very Large Telescope to perform near-infrared high-contrast imaging of AB Aur in polarized and unpolarized light in order to study the morphology of the disk and search for signs of planet formation. Results. SPHERE has delivered the deepest images ever obtained for AB Aur in scattered light. Among the many structures that are yet to be understood, we identified not only the inner spiral arms, but we also resolved a feature in the form of a twist in the eastern spiral at a separation of about 30 au. The twist of the spiral is perfectly reproduced with a planet-driven density wave model when projection effects are accounted for. We measured an azimuthal displacement with respect to the counterpart of this feature in the ALMA data, which is consistent with Keplerian motion on a 4 yr baseline. Another point sxce is detected near the edge of the inner ring, which is likely the result of scattering as opposed to the direct emission from a planet photosphere. We tentatively derived mass constraints for these two features. Conclusions. The twist and its apparent orbital motion could well be the first direct evidence of a connection between a protoplanet candidate and its manifestation as a spiral imprinted in the gas and dust distributions.

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Section: Discussionmentioning

confidence: 78%

Possible evidence of ongoing planet formation in AB Aurigae

Boccaletti

Folco

Pantin

et al. 2020

A&A

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“…5 assumes insteadṀ =Ṁ min = 5 × 10 −7 M J yr −1 in Eq. (4), corresponding to the lower limit on the accretion rate derived by Hashimoto et al (2020). Now, only small masses M p 1.5 M J are allowed since L acc raises everywhere L tot significantly.…”

Section: Constraints From the Luminosity On The Planetary Radius And mentioning

confidence: 91%

“…Later, a second planetary companion, PDS 70 c, was discovered by Haffert et al (2019) in Hα, together with a detection of Hα emission from PDS 70 b (see also Wagner et al 2018). Such measurements of hydrogen emission lines place constraints on the physics of the accretion flow and shock, extinction, and the mass and accretion rate of the planets (Thanathibodee et al 2019;Aoyama & Ikoma 2019;Hashimoto et al 2020).…”

Section: Introductionmentioning

confidence: 98%

MIRACLES: atmospheric characterization of directly imaged planets and substellar companions at 4–5 μm

Stolker

Marleau

Cugno

et al. 2020

A&A

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The circumstellar disk of PDS 70 hosts two forming planets, which are actively accreting gas from their environment. The physical and chemical characteristics of these planets remain ambiguous due to their unusual spectral appearance compared to more evolved objects. In this work, we report the first detection of PDS 70 b in the Brα and M′ filters with VLT/NACO, a tentative detection of PDS 70 c in Brα, and a reanalysis of archival NACO L′ and SPHERE H23 and K12 imaging data. The near side of the disk is also resolved with the Brα and M′ filters, indicating that scattered light is non-negligible at these wavelengths. The spectral energy distribution (SED) of PDS 70 b is well described by blackbody emission, for which we constrain the photospheric temperature and photospheric radius to Teff = 1193 ± 20 K and R = 3.0 ± 0.2 RJ. The relatively low bolometric luminosity, log(L∕L⊙) = −3.79 ± 0.02, in combination with the large radius, is not compatible with standard structure models of fully convective objects. With predictions from such models, and adopting a recent estimate of the accretion rate, we derive a planetary mass and radius in the range of Mp ≈ 0.5–1.5 MJ and Rp ≈ 1–2.5 RJ, independently of the age and post-formation entropy of the planet. The blackbody emission, large photospheric radius, and the discrepancy between the photospheric and planetary radius suggests that infrared observations probe an extended, dusty environment around the planet, which obscures the view on its molecular composition. Therefore, the SED is expected to trace the reprocessed radiation from the interior of the planet and/or partially from the accretion shock. The photospheric radius lies deep within the Hill sphere of the planet, which implies that PDS 70 b not only accretes gas but is also continuously replenished by dust. Finally, we derive a rough upper limit on the temperature and radius of potential excess emission from a circumplanetary disk, Teff ≲ 256 K and R ≲ 245 RJ, but we do find weak evidence that the current data favors a model with a single blackbody component.

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“…However, when they added a circumplanetary disk to their model they found a mass of M b ≈10 M Jup , which is above our upper limit. More recently, Hashimoto et al (2020) measured the width of the Hα line to estimate masses of 12±3 M Jup and 11±5 M Jup for PDS 70 b and c, respectively. We note that their mass estimate depends on the square of the freefall velocity, which is hard to measure directly, and was instead estimated using the accretion-shock model of Aoyama et al (2018) and the assumption that the Hα lines they measured were broadened beyond the instrumental resolution.…”

Section: Evolutionary Modelsmentioning

confidence: 99%

Keck/NIRC2 L’-band Imaging of Jovian-mass Accreting Protoplanets around PDS 70

Wang

Ginzburg

Ren

et al. 2020

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We present L'-band imaging of the PDS 70 planetary system with Keck/NIRC2 using the new infrared pyramid wave front sensor. We detected both PDS 70 b and c in our images, as well as the front rim of the circumstellar disk. After subtracting off a model of the disk, we measured the astrometry and photometry of both planets. Placing priors based on the dynamics of the system, we estimated PDS 70 b to have a semimajor axis of-+ 20 4 3 au and PDS 70 c to have a semimajor axis of-+ 34 6 12 au (95% credible interval). We fit the spectral energy distribution (SED) of both planets. For PDS 70 b, we were able to place better constraints on the red half of its SED than previous studies and inferred the radius of the photosphere to be 2-3R Jup. The SED of PDS 70 c is less well constrained, with a range of total luminosities spanning an order of magnitude. With our inferred radii and luminosities, we used evolutionary models of accreting protoplanets to derive a mass of PDS 70 b between 2 and 4 M Jup and a mean mass accretion rate between 3×10 −7 and 8×10 −7 M Jup /yr. For PDS 70 c, we computed a mass between 1 and 3 M Jup and mean mass accretion rate between 1×10 −7 and 5×10 −7 M Jup /yr. The mass accretion rates imply dust accretion timescales short enough to hide strong molecular absorption features in both planets' SEDs. Unified Astronomy Thesaurus concepts: Exoplanet formation (492); Exoplanet atmospheres (487); Orbit determination (1175); Exoplanet dynamics (490); Coronagraphic imaging (313);

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Accretion Properties of PDS 70b with MUSE*

Cited by 58 publications

References 48 publications

Possible evidence of ongoing planet formation in AB Aurigae

Possible evidence of ongoing planet formation in AB Aurigae

MIRACLES: atmospheric characterization of directly imaged planets and substellar companions at 4–5 μm

Keck/NIRC2 L’-band Imaging of Jovian-mass Accreting Protoplanets around PDS 70

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