J/A+A/712/L13 Optical spectroscopy of WISPIT 2 (Swastik+, 2026)
A quiet host in an active planet-Forming disk: Optical spectroscopy of WISPIT 2.
Swastik C., Bestha M., Sonith L.S., Facchini S., Sivarani T., Banyal R.K.,
Wahhaj Z., Choudhary A., Gopinathan M., Saraf P., Mallik A., Navaneeth M.P.,
Biswas S., Khushbu K.
<Astron. Astrophys. 712, L13 (2026)>
=2026A&A...712L..13S 2026A&A...712L..13S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Spectra, optical
Keywords: planets and satellites: gaseous planets - stars: abundances
Abstract:
WISPIT 2 is a young pre-main-sequence star hosting a multi-ringed
transition disk and two directly imaged accreting protoplanets, the
closest known analogue to PDS 70, yet its central star has no
published optical spectrum. Population-synthesis models predict that
stellar accretion can be strongly suppressed once two or more giant
planets have formed, so characterising the atmospheric and accretion
properties of such hosts is essential.
We present the first optical spectrum of WISPIT 2 and use it to derive
the host atmospheric parameters, test its youth spectroscopically, and
constrain its stellar accretion state relative to PDS 70 and to the
embedded planets. We analysed low-resolution HFOSC spectra (R about
1200 for Grism 7 and R about 2200 for Grism 8) from the 2-m Himalayan
Chandra Telescope with iSpec, validating the pipeline at HFOSC
resolution against Gaia FGK Benchmark Stars and K-type
pre-main-sequence templates from the public Manara et al. library. The
Halpha residual filling was measured relative to synthetic
photospheric profiles and compared with the chromospheric-noise level
of Manara et al. (2013A&A...551A.107M 2013A&A...551A.107M, Cat. J/A+A/551/A107).
Halpha remains in net absorption but is partially filled in by
emission. The weak residual filling, at 1.5-2.0 sigma, lies about 1dex
below the chromospheric-noise level, consistent with chromospheric
emission and no detectable accretion. We place a 95 percent upper
limit of dMacc/dt<3.6x10-11M☉/yr, below even the lowest
epoch of PDS 70 monitoring and implying a host-to-planet ratio
(dMstar/dt)/(dM2b_/dt)<18. We also measure Teff= 4551±150K and a
first, low-resolution, model-dependent global metallicity
[M/H]=-0.17± 0.16; the surface gravity and Li I equivalent width
support the pre-main-sequence nature of the host.
Both known double-protoplanet hosts, PDS 70 and WISPIT 2, therefore
appear to show strongly suppressed or undetectable stellar accretion.
Larger spectroscopic samples are needed to test whether this is common
in multi-protoplanet transition disks.
Description:
WISPIT 2 was observed on UT 2026-04-14 with HFOSC on the 2-m
Himalayan Chandra Telescope. One 600-s Grism 7 exposure has a useful
range of about 3800-7700 Angstrom at R about 1200. Three Grism 8
exposures of 600, 600, and 300s have a useful range of about
5200-9300 Angstrom at R about 2200.
The spectra were bias-subtracted, flat-fielded, cleaned of cosmic
rays, optimally extracted, wavelength-calibrated with FeAr/FeNe arcs,
and response-corrected using Feige 34.
The spectra contain the IRAF multispec band 1 flux and band 4
one-sigma uncertainty. They are trimmed only to the useful wavelength
ranges quoted in the paper. No wavelength resampling or interpolation
was applied in making these files.
Objects:
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RA (2000) DE Designation(s)
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19 23 17.03 -07 40 55.0 WISPIT 2 = TIC 98898373
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 150 4 List of fits spectra
fits/* . 4 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Nx Number of pixels along X-axis
6 I1 --- Ny Number of pixels along Y-axis
8- 33 A26 "datime" Obs.date Observation date
35- 41 F7.2 0.1nm Wmin First released wavelength
43- 49 F7.2 0.1nm Wmax Last released wavelength
51- 57 F7.5 0.1nm dW Wavelength resolution
59- 60 I2 Kibyte size Size of FITS file
62-100 A39 --- FileName Name of FITS file, in subdirectory fits
102-150 A49 --- Title Title of the FITS file
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Acknowledgements:
Chowbay Swastik,
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 20-Jul-2026