%ALópez-Valdivia, Ricardo%AMace, Gregory%AHan, Eunkyu%ASawczynec, Erica%AHernández, Jesús%APrato, L.%AJohns-Krull, Christopher%AOh, Heeyoung%ALee, Jae-Joon%AKraus, Adam%ALlama, Joe%AJaffe, Daniel%BJournal Name: The Astrophysical Journal; Journal Volume: 943; Journal Issue: 1; Related Information: CHORUS Timestamp: 2024-01-16 12:06:40 %D2023%IDOI PREFIX: 10.3847 %JJournal Name: The Astrophysical Journal; Journal Volume: 943; Journal Issue: 1; Related Information: CHORUS Timestamp: 2024-01-16 12:06:40 %K %MOSTI ID: 10392920 %PMedium: X; Size: Article No. 49 %TThe IGRINS YSO Survey. III. Stellar Parameters of Pre-main-sequence Stars in Ophiuchus and Upper Scorpius %XAbstract

We used the Immersion GRating Infrared Spectrometer (IGRINS) to determine fundamental parameters for 61 K- and M-type young stellar objects (YSOs) located in the Ophiuchus and Upper Scorpius star-forming regions. We employed synthetic spectra and a Markov chain Monte Carlo approach to fit specificK-band spectral regions and determine the photospheric temperature (T), surface gravity (logg), magnetic field strength (B), projected rotational velocity (vsini), andK-band veiling (rK). We determinedBfor ∼46% of our sample. Stellar parameters were compared to the results from Taurus-Auriga and the TW Hydrae association presented in Paper I of this series. We classified all the YSOs in the IGRINS survey with infrared spectral indices from Two Micron All Sky Survey and Wide-field Infrared Survey Explorer photometry between 2 and 24μm. We found that Class II YSOs typically have lowerloggandvsini, similarB, and higherK-band veiling than their Class III counterparts. Additionally, we determined the stellar parameters for a sample of K and M field stars also observed with IGRINS. We have identified intrinsic similarities and differences at different evolutionary stages with our homogeneous determination of stellar parameters in the IGRINS YSO survey. Consideringloggas a proxy for age, we found that the Ophiuchus and Taurus samples have a similar age. We also find that Upper Scorpius and TWA YSOs have similar ages, and are more evolved than Ophiuchus/Taurus YSOs.

%0Journal Article