J/A+A/708/A312 VLT/ERIS spectra 12 star with exoplanets (Hayoz+, 2026)
Observational constraints on the chemical tracers of planet formation history.
A systematic survey of 13 directly-imaged low-mass companions with VLT/ERIS.
Hayoz J., Bonse M.J., Garvin E.O., Cugno G., Dannert F., Kuehnle H.,
De Rosa R.J., Agudo Berbel A., Cao Y., Orban de Xivry G., Stolker T.,
Davies R., Absil O., Schmid H.M., Quanz S.P., Godoy N., Balmer W.O.,
Bowler B.P., Palma-Bifani P., Currie T., Chauvin G., Agapito G.,
Baruffolo A., Black M., Bonaglia M., Briguglio R., Carbonaro L., Cresci G.,
Dallilar Y., Deysenroth M., Di Antonio I., Di Cianno A., Di Rico G.,
Doelman D., Dolci M., Eisenhauer F., Esposito S., Fantinel D., Ferruzzi D.,
Feuchtgruber H., Foerster Schreiber N.M., Gao X., Genzel R., Gillessen S.,
Glauser A.M., Grani P., Hartl M., Henry D., Huber H., Keller C.,
Kenworthy M., Kravchenko K., Lightfoot J., Lunney D., Lutz D., MacIntosh M.,
Mannucci F., Ott T., Pearson D., Puglisi A., Rabien S., Rau C., Riccardi A.,
Salasnich B., Shimizu T., Snik F., Sturm E., Tacconi L., Taylor W.,
Valentini A., Waring C., Wiezorrek E., Xompero M.
<Astron. Astrophys. 708, A312 (2026)>
=2026A&A...708A.312H 2026A&A...708A.312H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Spectra, infrared
Keywords: techniques: high angular resolution -
techniques: imaging spectroscopy -
planets and satellites: atmospheres -
planets and satellites: formation - infrared: planetary systems
Abstract:
Constraining the link between the atmospheric composition of giant
exoplanets and their formation history is a key goal of exoplanet
studies. In particular, the atmospheric C/O ratio, metallicity, and CO
isotopologue ratio - which are readily measurable with direct
spectroscopic observations - are believed to be chemical tracers of
the birth location of substellar and planetary companions.
We aim to collect observational constraints for planet formation
theories by performing a large and systematic survey of the
atmospheric C/O ratio, metallicity, and isotopologue ratio.
We collected new K-band moderate-resolution R=11000 spectroscopic
observations of 13 directly-imaged planetary-mass companions spanning
the molecular snowlines of CO2, CO, and CH4 and with masses 4-30MJ
with VLT/ERIS/SPIFFIER.
Additionally, we gathered a large portion of the available archival
observations for these targets, amounting to 40 spectra and 140
photometric fluxes.
We performed spectral fits using self-consistent grid models and
freely parametrisable models. We obtained robust estimates of the key
atmospheric parameters by aggregating the results from the different
models, thereby reducing modelling systematics.
Using molecular mapping, we detect H2O and CO in 12 of our targets, as
well as 13CO in HR 2562 B. With our multimodel spectral fitting
strategy, we obtain stellar to superstellar C/O ratios - ranging
between 0.4 and 0.8 - and predominantly superstellar metallicities -
between -0.5 and 1.5dex - across all targets. We measure a substantial
enrichment of 13CO for HR 2562 B with
12CO/13CO=12.0+4.5-3.3. If corroborated by independent
observations, it could indicate that the companion might have formed
beyond the CO snowline and later migrated inwards to its current
location. We find an anti-correlation (R=-0.58) between the
atmospheric C/O ratio and the companion mass, consolidating previous
results.
Description:
This catalog presents new K-band VLT/ERIS/SPIFFIER spectra of 12 young
and low-mass companions. Additionally, this catalog includes a large
portion of the photometric and spectroscopic archival data available
for these companions. Together, all these datasets should facilitate
follow-up atmospheric retrieval studies on any or all of these
companions.
Objects:
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RA (2000) DE Designation(s)
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06 19 12.91 -58 03 15.5 AB Pic = HD 44627
05 27 04.76 -11 54 03.4 AF Lep = HR 1817
11 04 09.09 -76 27 19.3 CT Cha = Hen 3-566
06 50 01.01 -60 14 56.9 HR 2562 = HD 50571
23 07 28.71 +21 08 03.3 HR 8799 = HR 8799
16 26 28.03 -25 26 47.7 ROXs 12 = TIC 175595883
16 01 55.45 -21 58 49.3 HIP 78530 = HD 143567
16 31 15.01 -24 32 43.7 ROXs 42 B = WDS J16312-2434B
16 08 43.72 -23 41 07.5 HIP 79098 AB = HIP 79098
02 19 22.11 -39 25 22.5 2MASS J02192210-3925225 = TIC 77111651
12 56 02.13 -12 57 21.9 VHS J125601.92-125723.9 = TIC 2470992
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
phot.dat 249 103 List of photometric data for all 12 companions
analysed in the paper (table E2)
speceris.dat 161 12 List of ERIS/SPIFFIER spectroscopic data for
all 12 companions analysed in the paper
(table E1)
specarch.dat 275 55 List of archival spectroscopic data for all 12
companions analysed in the paper
spe/* . 12 Individual ERIS/SPIFFIER spectra
spa/* . 43 Individual archival spectra
spac/* . 3 Individual archival spectra
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Byte-by-byte Description of file: phot.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Index Index of the row
5- 29 A25 --- Name Name of the object
31- 32 I2 h RAh Right ascension (J2000)
34- 35 I2 min RAm Right ascension (J2000)
37- 42 F6.3 s RAs Right ascension (J2000)
44 A1 --- DE- Declination sign (J2000)
45- 46 I2 deg DEd Declination (J2000)
48- 49 I2 arcmin DEm Declination (J2000)
51- 56 F6.3 arcsec DEs Declination (J2000)
58- 64 A7 --- Obs Observatory
66- 96 A31 --- Filter Name of the filter
98-101 F4.2 um EffWvl Effective wavelength of the filter
103-106 F4.2 um EffWidth Effective width of the filter
108-112 F5.2 mag mag Apparent magnitude of the object
114-117 F4.2 mag e_mag Error of the apparent magnitude of
the object
119-140 E22.16 W/m2/um Flux Photometric flux of the object
142-163 E22.16 W/m2/um e_Flux Error of the photometric flux of the object
165-186 A22 --- Ref Reference paper for the photometry
188-249 A62 --- ADSlink ADS link to the paper
--------------------------------------------------------------------------------
Byte-by-byte Description of file: speceris.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Index Index of the row
4- 28 A25 --- Name Name of the object
30- 31 I2 h RAh Right ascension (J2000)
33- 34 I2 min RAm Right ascension (J2000)
36- 41 F6.3 s RAs Right ascension (J2000)
43 A1 --- DE- Declination sign (J2000)
44- 45 I2 deg DEd Declination (J2000)
47- 48 I2 arcmin DEm Declination (J2000)
50- 55 F6.3 arcsec DEs Declination (J2000)
57- 59 A3 --- Obs Observatory
61- 64 A4 --- Inst Instrument
66- 71 A6 --- Band Band
73- 84 A12 um WaveInt Wavelength interval
86- 92 F7.1 --- Res Spectral resolution
94-102 A9 --- Ref Reference paper for the spectroscopy
104-161 A58 --- FileName Name of the file containing the spectrum
with subdirectory
--------------------------------------------------------------------------------
Byte-by-byte Description of file: specarch.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Index Index of the row
4- 28 A25 --- Name Name of the object
30- 31 I2 h RAh Right ascension (J2000)
33- 34 I2 min RAm Right ascension (J2000)
36- 41 F6.3 s RAs Right ascension (J2000)
43 A1 --- DE- Declination sign (J2000)
44- 45 I2 deg DEd Declination (J2000)
47- 48 I2 arcmin DEm Declination (J2000)
50- 55 F6.3 arcsec DEs Declination (J2000)
57- 62 A6 --- Obs Observatory
64- 79 A16 --- Inst Instrument
81- 92 A12 --- Band Band
94-105 A12 um WaveInt Wavelength interval
107-114 F8.1 --- Res Spectral resolution
116-139 A24 --- Ref Reference paper for the spectroscopy
141-212 A72 --- FileName Name of the file containing the spectrum
with subdirectory
214-275 A62 --- ADSlink ADS link to the paper
--------------------------------------------------------------------------------
Byte-by-byte Description of file: spe/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Index Index of the row
6- 23 F18.16 um lambda Wavelength
25- 47 E23.20 --- Flux Flux
49- 71 F23.17 --- e_Flux Error
--------------------------------------------------------------------------------
Byte-by-byte Description of file: spa/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Index Index
5- 23 F19.16 um lambda Wavelength
25- 46 E22.16 W/m2/um Flux Flux
48- 69 E22.16 W/m2/um e_Flux Flux error
--------------------------------------------------------------------------------
Byte-by-byte Description of file: spac/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- Index Index
5- 22 F18.16 um lambda Wavelength
24- 46 E23.16 W/m2/um Flux Flux
48- 70 E23.16 --- cov-0 Column of the covariance matrix
72- 94 E23.16 --- cov-1 Column of the covariance matrix
96-118 E23.16 --- cov-2 Column of the covariance matrix
120-142 E23.16 --- cov-3 Column of the covariance matrix
144-166 E23.16 --- cov-4 Column of the covariance matrix
168-190 E23.16 --- cov-5 Column of the covariance matrix
192-214 E23.16 --- cov-6 Column of the covariance matrix
216-238 E23.16 --- cov-7 Column of the covariance matrix
240-262 E23.16 --- cov-8 Column of the covariance matrix
264-286 E23.16 --- cov-9 Column of the covariance matrix
288-310 E23.16 --- cov-10 Column of the covariance matrix
312-334 E23.16 --- cov-11 Column of the covariance matrix
336-358 E23.16 --- cov-12 Column of the covariance matrix
360-382 E23.16 --- cov-13 Column of the covariance matrix
384-406 E23.16 --- cov-14 Column of the covariance matrix
408-430 E23.16 --- cov-15 Column of the covariance matrix
432-454 E23.16 --- cov-16 Column of the covariance matrix
456-478 E23.16 --- cov-17 Column of the covariance matrix
480-502 E23.16 --- cov-18 Column of the covariance matrix
504-526 E23.16 --- cov-19 Column of the covariance matrix
528-550 E23.16 --- cov-20 Column of the covariance matrix
552-574 E23.16 --- cov-21 Column of the covariance matrix
576-598 E23.16 --- cov-22 Column of the covariance matrix
600-622 E23.16 --- cov-23 Column of the covariance matrix
624-646 E23.16 --- cov-24 Column of the covariance matrix
648-670 E23.16 --- cov-25 Column of the covariance matrix
672-694 E23.16 --- cov-26 Column of the covariance matrix
696-718 E23.16 --- cov-27 Column of the covariance matrix
720-742 E23.16 --- cov-28 Column of the covariance matrix
744-766 E23.16 --- cov-29 Column of the covariance matrix
768-790 E23.16 --- cov-30 Column of the covariance matrix
792-814 E23.16 --- cov-31 Column of the covariance matrix
816-838 E23.16 --- cov-32 Column of the covariance matrix
840-862 E23.16 --- cov-33 ? Column of the covariance matrix
864-886 E23.16 --- cov-34 ? Column of the covariance matrix
888-910 E23.16 --- cov-35 ? Column of the covariance matrix
912-934 E23.16 --- cov-36 ? Column of the covariance matrix
936-958 E23.16 --- cov-37 ? Column of the covariance matrix
960-982 E23.16 --- cov-38 ? Column of the covariance matrix
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Acknowledgements:
Jean Hayoz, jeanhayoz94(at)gmail.com
(End) Patricia Vannier [CDS] 25-Jan-2026