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Rigliaco, E., Gratton, R., Mesa, D., D'Orazi, V., Bonnefoy, M., Alcalà, J. M., . . . Weber, L. (2019). Investigating the nature of the extended structure around the Herbig star RCrA using integral field and high-resolution spectroscopy. Astronomy and Astrophysics, 632, Article ID A18.
Open this publication in new window or tab >>Investigating the nature of the extended structure around the Herbig star RCrA using integral field and high-resolution spectroscopy
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2019 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 632, article id A18Article in journal (Refereed) Published
Abstract [en]

Context. We present a detailed analysis of the extended structure detected around the young and close-by Herbig Ae/Be star R CrA. This is a young triple system with an intermediate mass central binary whose separation is of the order of a few tens of the radii of the individual components, and an M-star companion at about 30 au.

Aims. Our aim is to understand the nature of the extended structure by means of combining integral-field and high-resolution spectroscopy.

Methods. We conducted the analysis based on FEROS archival optical spectroscopy data and adaptive optics images and integral-field spectra obtained with SINFONI and SPHERE at the VLT.

Results. The observations reveal a complex extended structure that is composed of at least two components: a non-uniform wide cavity whose walls are detected in continuum emission up to 400 au, and a collimated wiggling-jet detected in the emission lines of helium and hydrogen. Moreover, the presence of [Fe II] emission projected close to the cavity walls suggests the presence of a slower moving wind, most likely a disk wind. The multiple components of the optical forbidden lines also indicate the presence of a high-velocity jet co-existing with a slow wind. We constructed a geometrical model of the collimated jet flowing within the cavity using intensity and velocity maps, finding that its wiggling is consistent with the orbital period of the central binary. The cavity and the jet do not share the same position angle, suggesting that the jet is itself experiencing a precession motion possibly due to the wide M-dwarf companion.

Conclusions. We propose a scenario that closely agrees with the general expectation of a magneto-centrifugal-launched jet. These results build upon the extensive studies already conducted on R CrA.

Keywords
stars: pre-main sequence, protoplanetary disks, Herbig-Haro objects, ISM: jets and outflows, ISM: individual objects: R CrA
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-180679 (URN)10.1051/0004-6361/201936707 (DOI)000515109600001 ()
Available from: 2020-04-06 Created: 2020-04-06 Last updated: 2022-02-26Bibliographically approved
Mesa, D., Keppler, M., Cantalloube, F., Rodet, L., Charnay, B., Gratton, R., . . . Wildi, F. (2019). VLT/SPHERE exploration of the young multiplanetary system PDS70. Astronomy and Astrophysics, 632, Article ID A25.
Open this publication in new window or tab >>VLT/SPHERE exploration of the young multiplanetary system PDS70
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2019 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 632, article id A25Article in journal (Refereed) Published
Abstract [en]

Context. PDS 70 is a young (5.4 Myr), nearby (similar to 113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) allowed us to detect a planetary mass companion, PDS 70 b, within the disk cavity. Moreover, observations in H-alpha with MagAO and MUSE revealed emission associated to PDS 70 b and to another new companion candidate, PDS 70 c, at a larger separation from the star. PDS 70 is the only multiple planetary system at its formation stage detected so far through direct imaging.

Aims. Our aim is to confirm the discovery of the second planet PDS 70 c using SPHERE at VLT, to further characterize its physical properties, and search for additional point sources in this young planetary system.

Methods. We re-analyzed archival SPHERE NIR observations and obtained new data in Y, J, H and K spectral bands for a total of four different epochs. The data were reduced using the data reduction and handling pipeline and the SPHERE data center. We then applied custom routines (e.g., ANDROMEDA and PACO) to subtract the starlight.

Results. We re-detect both PDS 70 b and c and confirm that PDS 70 c is gravitationally bound to the star. We estimate this second planet to be less massive than 5 M-Jup and with a T-eff around 900 K. Also, it has a low gravity with log g between 3.0 and 3.5 dex. In addition, a third object has been identified at short separation (similar to 0.12 '') from the star and gravitationally bound to the star. Its spectrum is however very blue, meaning that we are probably seeing stellar light reflected by dust and our analysis seems to demonstrate that it is a feature of the inner disk. We cannot however completely exclude the possibility that it is a planetary mass object enshrouded by a dust envelope. In this latter case, its mass should be of the order of a few tens of M-circle plus. Moreover, we propose a possible structure for the planetary system based on our data, and find that this structure cannot be stable on a long timescale.

Keywords
instrumentation: spectrographs, methods: data analysis, techniques: imaging spectroscopy, planetary systems, stars: individual: PDS70
National Category
Physical Sciences
Identifiers
urn:nbn:se:su:diva-180678 (URN)10.1051/0004-6361/201936764 (DOI)000515111200001 ()
Available from: 2020-04-06 Created: 2020-04-06 Last updated: 2022-02-26Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0666-3847

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