Imaging & Spectroscopy

Exploring The Directly Imaged HD 1160 System Through Spectroscopic Characterisation And High-cadence Variability Monitoring

By Keith Cowing
Status Report
May 23, 2024
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Exploring The Directly Imaged HD 1160 System Through Spectroscopic Characterisation And High-cadence Variability Monitoring
Left panel: A single frame of data from the 3.69 μm wavelength channel, overplotted with the apertures and annuli used to obtain flux and background measurements for the host star HD 1160 A (in orange) and companion HD 1160 B (in purple). The dashed lines indicate the background annuli. Each image uses a different arbitrary logarithmic colour scale, and both are north-aligned, where north is up and east is to the left. Right panel: the final LBT/ALES+dgvAPP360 image of the HD 1160 system from the second night, produced by taking the median combination of all frames in the 3.59-3.99 μm range over both time and wavelength. This image covers a total integration time of 10800 s (3 h). — astro-ph.SR

The time variability and spectra of directly imaged companions provide insight into their physical properties and atmospheric dynamics.

We present follow-up R~40 spectrophotometric monitoring of red companion HD 1160 B at 2.8-4.2 μm using the double-grating 360° vector Apodizing Phase Plate (dgvAPP360) coronagraph and ALES integral field spectrograph on the Large Binocular Telescope Interferometer. We use the recently developed technique of gvAPP-enabled differential spectrophotometry to produce differential light curves for HD 1160 B.

We reproduce the previously reported ~3.2 h periodic variability in archival data, but detect no periodic variability in new observations taken the following night with a similar 3.5% level precision, suggesting rapid evolution in the variability of HD 1160 B. We also extract complementary spectra of HD 1160 B for each night. The two are mostly consistent, but the companion appears fainter on the second night between 3.0-3.2 μm. Fitting models to these spectra produces different values for physical properties depending on the night considered. We find an effective temperature Teff = 2794+115−133 K on the first night, consistent with the literature, but a cooler Teff = 2279+79−157 K on the next.

We estimate the mass of HD 1160 B to be 16-81 MJup, depending on its age. We also present R = 50,000 high-resolution optical spectroscopy of host star HD 1160 A obtained simultaneously with the PEPSI spectrograph. We reclassify its spectral type to A1 IV-V and measure its projected rotational velocity v sin i = 96+6−4 km s−1. We thus highlight that gvAPP-enabled differential spectrophotometry can achieve repeatable few percent level precision and does not yet reach a systematic noise floor, suggesting greater precision is achievable with additional data or advanced detrending techniques.

Ben J. Sutlieff, Jayne L. Birkby, Jordan M. Stone, Annelotte Derkink, Frank Backs, David S. Doelman, Matthew A. Kenworthy, Alexander J. Bohn, Steve Ertel, Frans Snik, Charles E. Woodward, Ilya Ilyin, Andrew J. Skemer, Jarron M. Leisenring, Klaus G. Strassmeier, Ji Wang, David Charbonneau, Beth A. Biller

Comments: 22 pages, 12 figures, accepted for publication in MNRAS
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2405.12271 [astro-ph.SR] (or arXiv:2405.12271v1 [astro-ph.SR] for this version)
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Submission history
From: Ben Sutlieff
[v1] Mon, 20 May 2024 18:00:00 UTC (2,565 KB)


Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻