Detection of H$\alpha$ emission from PZ Tel B using SPHERE/ZIMPOL

Abstract

H$\alpha$ is a powerful tracer of accretion and chromospheric activity, which has been detected in the case of young brown dwarfs and even recently in planetary mass companions (e.g. PDS70 b and c). H$\alpha$ detections and characterisation of brown dwarf and planet companions can further our knowledge of their formation and evolution, and expanding such a sample is therefore our primary goal. We used the Zurich IMaging POLarimeter (ZIMPOL) of the SPHERE instrument at the Very Large Telescope (VLT) to observe the known $38-72$M${}_{\mathrm{J}}$ companion orbiting PZ Tel, obtaining simultaneous angular differential imaging observations in both continuum and narrow H$\alpha$ band. We detect H$\alpha$ emission from the companion, making this only the second H$\alpha$ detection of a companion using the SPHERE instrument. We used our newly added astrometric measurements to update the orbital analysis of PZ Tel B, and we used our photometric measurements to evaluate the H$\alpha$ line flux. Given the estimated bolometric luminosity, we obtained an H$\alpha$ activity (log$({\mathrm{L}}_{\mathrm{H}\alpha }/{\mathrm{L}}_{\mathrm{bol}})$) between $-4.16$ and $-4.31$. The H$\alpha$ activity of PZ Tel B is consistent with known average activity levels for M dwarf of the same spectral type. Given the absence of a known gaseous disk and the relatively old age of the system (24 Myr), we conclude that the H$\alpha$ emission around PZ Tel B is likely due to chromospheric activity.

arXiv comment9 pages, 4 figures, to be published in Astronomy & Astrophysics

References in corpus (38)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• Gaia Data Release 2. Summary of the contents and survey properties
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• Angular Differential Imaging: a Powerful High-Contrast Imaging Technique
• The MUSE second-generation VLT instrument
• Evolutionary models for low-mass stars and brown dwarfs: uncertainties and limits at very young ages
• A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood
• Improving the Efficiency of Markov Chain Monte Carlo for Analyzing the Orbits of Extrasolar Planets
• Spectroscopic Properties of Cool Stars in the SDSS: An Analysis of Magnetic Activity and a Search for Subdwarfs
• Accreting Protoplanets in the LkCa 15 Transition Disk
• The Gemini NICI Planet-Finding Campaign: The Frequency of Planets around Young Moving Group Stars
• Magellan Adaptive Optics Imaging of PDS 70: Measuring the Mass Accretion Rate of a Young Giant Planet within a Gapped Disk
• The Gemini NICI Planet-Finding Campaign: Discovery of a Close Substellar Companion to the Young Debris Disk Star PZ Tel
• Discovery of H-alpha Emission from the Close Companion Inside the Gap of Transitional Disk HD142527
• SPHERE / ZIMPOL high resolution polarimetric imager. I. System overview, PSF parameters, coronagraphy, and polarimetry
• First light of the VLT planet finder SPHERE. II. The physical properties and the architecture of the young systems PZ Tel and HD 1160 revisited
• Direct exoplanet detection and characterization using the ANDROMEDA method: Performance on VLT/NaCo data
• Optical atmospheric extinction over Cerro Paranal
• H-alpha Activity of Old M Dwarfs: Stellar Cycles and Mean Activity Levels For 93 Low-Mass Stars in the Solar Neighborhood
• Accretion onto Planetary Mass Companions of Low-Mass Young Stars
• No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals
• Spectroscopic Confirmation of Young Planetary-Mass Companions on Wide Orbits
• Gas and dust in the Beta Pictoris Moving Group as seen by the Herschel Space Observatory
• A search for accreting young companions embedded in circumstellar disks: High-contrast H$\alpha$ imaging with VLT/SPHERE
• VLT/SPHERE robust astrometry of the HR8799 planets at milliarcsecond-level accuracy Orbital architecture analysis with PyAstrOFit
• Resolving the planet-hosting inner regions of the LkCa 15 disk
• Astrometric follow-up observations of directly imaged sub-stellar companions to young stars and brown dwarfs
• Thermodynamics of Giant Planet Formation: Shocking Hot Surfaces on Circumplanetary Disks
• Short-Term H-alpha Variability in M Dwarfs
• SPHERE / ZIMPOL observations of the symbiotic system R Aqr. I. Imaging of the stellar binary and the innermost jet clouds
• Direct detection of a substellar companion to the young nearby star PZ Telescopii
• Chromospheric Variability in SDSS M Dwarfs. II. Short-Timescale H-alpha Variability
• Accretion signatures in the X-shooter spectrum of the substellar companion to SR12
• Benchmark cool companions: Ages and abundances for the PZ Tel system
• First spectroscopic observations of the sub-stellar companion of the young debris disk star PZ Telescopii
• Orbital fitting of imaged planetary companions with high eccentricities and unbound orbits -- Application to Fomalhaut b and PZ Telescopii B

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