J/MNRAS/543/420 YSOs parameters and abundances. I. Orion (Lopez-Valdivia+, 2025)
Atmospheric parameters and chemical abundances of young stars with APOGEE.
I. Orion star-forming region.
Lopez-Valdivia R., Adame L., Roman-Zuniga C.G., Hernandez J., Sanchez E.,
Herrnandez-Aburto I., Fernandez-Trincado J.G., Zagala Lagunas E., Carigi L.,
Mendez-Delgado J.E., Kounkel M., Serna J., Lane R.R., Stassun K.G.,
Villanova S., Kim J.S., Wolk S.J., Stringfellow G.S., Tan J.C.,
Roman-Lopes A., Rojas-Ayala B., Pandey R.
<Mon. Not. R. Astron. Soc. 543, 420-434 (2025)>
=2025MNRAS.543..420L 2025MNRAS.543..420L (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Protostars ; Abundances
Keywords: stars: abundances - stars: fundamental parameters -
stars: pre-main-sequence - infrared: stars
Abstract:
We derive atmospheric parameters and chemical abundances in young G-,
K-, and M-type stars (temperatures between 6500 and 3100K) using
infrared APOGEE-2 spectra. Atmospheric parameters were determined for
548 young stars in the Orion complex (Orion A, B, OB1, and λ
Ori) using the TONALLI code. For 340 slow rotators (vsini≤30km/s,
we derived C, Mg, Si, K, Ti, and Fe abundances using 19 atomic lines,
MARCS model atmospheres, and BACCHUS. To mitigate the impact of
circumstellar material, we excluded stars with infrared excess
identified via 2MASS and WISE photometry. We find sub-solar [X/H]
abundance ratios, consistent across elements and among all four
groups, suggesting a chemically homogeneous Orion complex. We computed
α/Fe] from [Mg/Fe], [Si/Fe], and [Ti/Fe], obtaining a median
of -0.14±0.04, about 0.10dex lower than the value for nearby
main-sequence stars (-0.04±0.04) at similar [Fe/H]. This result
aligns with predictions from Galactic chemical evolution models.
Furthermore, the median [C/H] abundance we derived for Orion agrees
with previous estimations based on the analysis of the ionized gas of
the Orion nebula. This work sets the stage for extending the analysis
to stars with circumstellar material and higher rotational velocities,
which will not only improve our understanding of Orion, but also
provide critical insight into the formation and evolution of young
stars, as well as the chemical evolution of the Milky Way.
Description:
This catalog presents the atmospheric parameters for 548 G, K, and M
pre-main-sequence stars of Orion. For more than 300 of these stars,
the catalog also contains chemical abundances of at least two elements
among the six studied.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 281 548 Atmospheric parameters for 548 G, K, and M
pre-main-sequence stars of Orion
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name 2MASS identification number,
2MHHMMSSss+DDMMSSs
20- 28 F9.6 deg RAdeg Right Ascencion (J2000)
30- 36 F7.4 deg DEdeg Declination (J2000)
38- 44 F7.2 K Teff25 Effective temperature at percentile 25
46- 51 F6.1 K Teff50 Effective temperature at percentile 50
53- 59 F7.2 K Teff75 Effective temperature at percentile 75
61- 64 F4.2 [cm/s2] logg25 Surface gravity at percentile 25
66- 69 F4.2 [cm/s2] logg50 Surface gravity at percentile 50
71- 74 F4.2 [cm/s2] logg75 Surface gravity at percentile 75
76- 80 F5.2 --- [M/H]25 Overall metallicity at percentile 25
82- 86 F5.2 --- [M/H]50 Overall metallicity at percentile 50
88- 92 F5.2 --- [M/H]75 Overall metallicity at percentile 75
94- 98 F5.2 --- alpha25 alpha elements abundance at percentile 25
100-104 F5.2 --- alpha50 alpha elements abundance at percentile 50
106-110 F5.2 --- alpha75 alpha elements abundance at percentile 75
112-116 F5.2 km/s v25 Projected rotational velocity at
percentile 25
118-122 F5.2 km/s v50 Projected rotational velocity at
percentile 50
124-128 F5.2 km/s v75 Projected rotational velocity at
percentile 75
130-134 F5.2 --- [C/H] ? Mean [C/H] abundance
136-140 F5.3 --- e_[C/H] ? Lower error on carbon abundance
142-146 F5.3 --- E_[C/H] ? Upper error on carbon abundance
148-150 F3.1 --- o_[C/H] ? Number of lines used in carbon abundance
determination
152-157 F6.3 --- [Mg/H] ? Mean [Mg/H] abundance
159-163 F5.3 --- e_[Mg/H] ? Lower error on magnesium abundance
165-169 F5.3 --- E_[Mg/H] ? Upper error on magnesium abundance
171-173 F3.1 --- o_[Mg/H] ? Lines used in magnesium abundance
determination
175-180 F6.3 --- [Si/H] ? Mean [Si/H] abundance
182-186 F5.3 --- e_[Si/H] ? Lower error on silicon abundance
188-192 F5.3 --- E_[Si/H] ? Upper error on silicon abundance
194-196 F3.1 --- o_[Si/H] ? Lines used in silicon abundance
determination
198-203 F6.3 --- [K/H] ? Mean [K/H] abundance
205-209 F5.3 --- e_[K/H] ? Lower error on potassium abundance
211-215 F5.3 --- E_[K/H] ? Upper error on potassium abundance
217-219 F3.1 --- o_[K/H] ? Lines used in potassium abundance
determination
221-225 F5.2 --- [Ti/H] ? Mean [Ti/H] abundance
227-231 F5.3 --- e_[Ti/H] ? Lower error in titanium abundance
233-237 F5.3 --- E_[Ti/H] ? Upper error in titanium abundance
239-241 F3.1 --- o_[Ti/H] ? Lines used in titanium abundance
determination
243-248 F6.3 --- [Fe/H] ? Mean [Fe/H] abundance
250-254 F5.3 --- e_[Fe/H] ? Lower error in iron abundance
256-260 F5.3 --- E_[Fe/H] ? Upper error in iron abundance
262-264 F3.1 --- o_[Fe/H] ? Lines used in iron abundance determination
266-268 F3.1 km/s vmic ? Microturbulence velocity
270-275 F6.3 --- [alpha/Fe] ? alpha-elements to iron abundance ratio
277-281 F5.3 --- e_[alpha/Fe] ? Error in alpha-elements to iron abundance
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Acknowledgements:
Ricardo Lopez-Valdivia, rlopezv(at)astro.unam.mx
(End) Patricia Vannier [CDS] 01-Sep-2025