J/ApJ/945/L7 JWST/MIRI MRS sp. of EX Lup taken in quiescence (Kospal+, 2023)
JWST/MIRI spectroscopy of the disk of the young eruptive star EX Lup in
quiescence.
Kospal A., Abraham P., Diehl L., Banzatti A., Bouwman J., Chen L.,
Cruz-Saenz de Miera F., Green J.D., Henning T., Rab C.
<Astrophys. J., 945, L7 (2023)>
=2023ApJ...945L...7K 2023ApJ...945L...7K
ADC_Keywords: Spectra, infrared; Stars, variable; Stars, pre-main sequence
Keywords: Protoplanetary disks ; Eruptive variable stars ; Low mass stars ;
Infrared spectroscopy
Abstract:
EX Lup is a low-mass pre-main-sequence star that occasionally shows
accretion-related outbursts. Here, we present JWST/MIRI
medium-resolution spectroscopy obtained for EX Lup 14 yr after its
powerful outburst. EX Lup is now in quiescence and displays a Class II
spectrum. We detect a forest of emission lines from molecules
previously identified in infrared spectra of classical T Tauri disks:
H2O, OH, H2, HCN, C2H2, and CO2. The detection of organic molecules
demonstrates that they are back after disappearing during the large
outburst. Spectral lines from water and OH are for the first time
deblended and will provide a much-improved characterization of their
distribution and density in the inner disk. The spectrum also shows
broad emission bands from warm, submicron-size amorphous silicate
grains at 10 and 18µm. During the outburst, in 2008, crystalline
forsterite grains were annealed in the inner disk within 1au, but
their spectral signatures in the 10µm silicate band later
disappeared. With JWST we rediscovered these crystals via their 19.0,
20.0, and 23.5µm emission, the strength of which implies that the
particles are at ∼3au from the star. This suggests that crystalline
grains formed in 2008 were transported outwards and now approach the
water snowline, where they may be incorporated into planetesimals.
Containing several key tracers of planetesimal and planet formation,
EX Lup is an ideal laboratory to study the effects of variable
luminosity on the planet-forming material and may provide an
explanation for the observed high crystalline fraction in solar system
comets.
Description:
We obtained JWST's Mid-Infrared Instrument (MIRI) medium-resolution
spectrometer (MRS) spectroscopy of EX Lup on 2022 August 23 (GO 2209,
PI: P. Abraham). We used all four channels and all three sub-bands,
covering 4.9-28um at a spectral resolution of 3500-1500. We observed a
separate background 193.5" away from EX Lup, centered at
RA(J2000)=16:03:12.63,DE(J2000)=-40:15:30.42. Exposure time was 344.1s
for the science target and 41.6s for the background.
The final spectrum is plotted in Figure 1. As representative values,
we reached signal-to-noise ratios (S/Ns) of 120 at 9.0um, 100 at
15.5um, and 60 at 25.0um on the continuum.
Objects:
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RA (ICRS) DE Designation(s)
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16 03 05.49 -40 18 25.4 EX Lup = V* EX Lup
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig1.dat 27 10721 JWST/MIRI MRS spectrum of EX Lup
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See also:
J/ApJS/147/305 : IUE atlas of pre-main-sequence stars (Valenti+, 2003)
J/ApJ/678/985 : c2d Spitzer survey of interstellar ices. I. (Boogert+, 2008)
J/A+A/507/881 : Emission lines in EX Lup optical spectrum (Sipos+, 2009)
J/ApJS/201/11 : MIR spectral variability atlas of YSOs (Kospal+, 2012)
J/PASP/125/477 : Gas Survey of Protoplanetary Systems. I. (Dent+, 2013)
J/A+A/630/A58 : Full infrared spectrum of molecular hydrogen (Roueff+, 2019)
J/A+A/636/A74 : HARPS radial velocity database (Trifonov+, 2020)
J/A+A/641/A33 : EX Lup SPHERE and SINFONI images (Rigliaco+, 2020)
J/AJ/163/174 : IRTF/VLT M-band spectroscopic survey (Banzatti+, 2022)
J/AJ/165/72 : IR water vapor em. from planet-forming disks (Banzatti+, 2023)
J/MNRAS/526/4885 : Stable accretion of EX Lup & TW Hya (Sicilia-Aguilar+, 2023)
J/A+A/684/A73 : Polarimetric Diff. Imaging with VLT/NACO (de Regt+, 2024)
J/A+A/691/A18 : EX Lup ESPaDOnS and SPIRou spectra (Pouilly+, 2024)
Byte-by-byte Description of file: fig1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.4 um lambda [4.9/28] Wavelength
9- 16 F8.6 Jy Flux [0.18/1.16] Flux
18- 27 A10 --- Channel MIRI MRS channel (ch1 to ch4) and
sub-band (short, medium, or long) (1)
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Note (1): JWST/MIRI IFU channels (flight-measured):
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FOV name Sub-band λ-range Resolving power
name (µm) (λ/Δλ)
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channel1 short 4.90- 5.74 3320-3710
medium 5.66- 6.63 3190-3750
long 6.53- 7.65 3100-3610
channel2 short 7.51- 8.77 2990-3110
medium 8.67-10.13 2750-3170
long 10.01-11.70 2860-3300
channel3 short 11.55-13.47 2530-2880
medium 13.34-15.57 1790-2640
long 15.41-17.98 1980-2790
channel4 short 17.70-20.95 1460-1930
medium 20.69-24.48 1680-1770
long 24.40-27.90 1630-1330
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Feb-2025