J/AJ/164/201 Accretion in 9 Orion OB1b T-Tauri stars (Pittman+, 2022) ================================================================================ Towards a Comprehensive View of Accretion, Inner Disks, and Extinction in Classical T Tauri Stars; An ODYSSEUS Study of the Orion OB1b Association. Pittman C.V., Espaillat C.C., Robinson C.E., Thanathibodee T., Calvet N., Wendeborn J., Hernandez J., Manara C.F., Walter F., Abraham P., Alcala J.M., Alencar S.H.P., Arulanantham N., Cabrit S., Eisloffel J., Fiorellino E., France K., Gangi M., Grankin K., Herczeg G.J., Kospal A., Mendigutia I., Serna J., Venuti L. =2022AJ....164..201P ================================================================================ ADC_Keywords: Associations, stellar; Stars, pre-main sequence; Accretion; Spectra, ultraviolet; Spectra, optical; Spectra, infrared Keywords: Pre-main sequence stars ; Stellar accretion ; Stellar accretion disks ; Protoplanetary disks ; Reddening law ; Interstellar extinction ; Hubble Space Telescope ; Very Large Telescope Abstract: The coevolution of T-Tauri stars and their surrounding protoplanetary disks dictates the timescales of planet formation. In this paper, we present magnetospheric accretion and inner disk wall model fits to near-UV (NUV) to near-IR (NIR) spectra of nine classical T-Tauri stars in Orion OB1b as part of the Outflows and Disks around Young Stars: Synergies for the Exploration of ULLYSES Spectra (ODYSSEUS) survey. Using NUV-optical spectra from the Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Director's Discretionary Program and optical-NIR spectra from the PENELLOPE VLT Large Programme, we find that the accretion rates of these targets are relatively high for the region's intermediate age of 5.0Myr; rates are in the range of (0.5-17.2)x10^-8^M{sun}/yr, with a median value of 1.2x10^-8^M{sun}/yr. The NIR excesses can be fit with 1200-1800K inner disk walls located at 0.05-0.10au from the host stars. We discuss the significance of the choice in extinction law, as the measured accretion rate depends strongly on the adopted extinction value. This analysis will be extended to the complete sample of T-Tauri stars being observed through ULLYSES to characterize accretion and inner disks in star-forming regions of different ages and stellar populations. Description: The Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) program began observations with a sample of eight coevolution of T-Tauri stars (CTTSs) in the Orion OB1b subassociation and two weak-lined TTSs (WTTSs; non-accreting sources) in the 25 Ori cluster. Each target was observed with both Hubble Space Telescope (HST) and the Very Large Telescope (VLT) contemporaneously. Objects: ----------------------------------------------------- RA (ICRS) DE Designation(s) ----------------------------------------------------- 05 34 00.00 -01 30 00.0 Orion OB1b = Ass Ori OB 1b 05 24 44.82 +01 50 47.2 25 Ori = * 25 Ori ----------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table3.dat 176 9 Best-fit accretion shock model parameters of Orion OB1 CTTS table4.dat 40 9 Periods and inclinations of Orion OB1 CTTS table7.dat 42 9 Accretion column temperatures table8.dat 95 9 Accretion column mass flux rates fig1.dat 62 9 Model parameters for the 9 sources -------------------------------------------------------------------------------- See also: II/362 : I-band variability of YSOs (Sergison+, 2020) J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995) J/AJ/129/907 : New Ori OB1 members (Briceno+, 2005) J/ApJ/756/171 : HST far-UV survey H2 emission of T Tau stars (France+, 2012) J/A+A/551/A107 : X-shooter spectra of 24 young stellar objects (Manara+, 2013) J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013) J/A+A/570/A82 : Mapping accretion variability in NGC 2264 (Venuti+, 2014) J/A+A/600/A20 : Lupus YSOs X-shooter spectroscopy (Alcala+, 2017) J/A+A/605/A86 : Pre-main sequence stars VLT/X-Shooter spectra (Manara+, 2017) J/A+A/599/A23 : Accretion-rotation connection in NGC 2264 (Venuti+, 2017) J/AJ/157/85 : The CIDA Variability Survey of Orion OB1. II. (Briceno+, 2019) J/AJ/157/196 : Close companions around young stars (Kounkel+, 2019) J/AJ/160/268 : Infrared photometry of binaries Orion OB1 (Tokovinin+, 2020) Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- ID Object identifier 11- 14 F4.2 mag AV [0.05/1.44] V band extinction 16- 19 F4.2 mag E_AV [0.02/0.05] Upper uncertainty in AV 21- 24 F4.2 mag e_AV [0.02/0.4] Lower uncertainty in AV 26- 29 F4.2 Rsun Rad [0.84/3.26] Stellar radius 31- 34 F4.2 Rsun E_Rad [0.07/0.4] Upper uncertainty in Rad 36- 39 F4.2 Rsun e_Rad [0.07/0.4] Lower uncertainty in Rad 41- 44 F4.2 Lsun Lum [0.12/1.18] Stellar luminosity 46- 49 F4.2 Lsun e_Lum [0.03/0.3] Uncertainty in Lum 51- 56 F6.4 Lsun Lacc [0.06/0.61] Accretion luminosity 58- 63 F6.4 Lsun E_Lacc [0.00/0.04] Upper uncertainty in Lacc 65- 70 F6.4 Lsun e_Lacc [0.00/0.23] Lower uncertainty in Lacc 72- 77 F6.3 10-8Msun/yr dMass [0.53/17.2] Accretion rate 79- 83 F5.3 10-8Msun/yr E_dMass [0.01/1] Upper uncertainty in dMass 85- 89 F5.3 10-8Msun/yr e_dMass [0.01/7] Lower uncertainty in dMass 91- 97 F7.5 --- f1E10 [0.0001/0.24] 1e^10^ accretion column stellar surface fraction covered 99-104 F6.4 --- E_f1E10 [0.0004/0.02] Upper uncertainty in f1E10 106-112 F7.5 --- e_f1E10 [7e-05/0.03] Lower uncertainty in f1E10 114-120 F7.5 --- f1E11 [9e-05/0.02] 1e^11^ accretion column stellar surface fraction covered 122-128 F7.5 --- E_f1E11 [0.0001/0.03] Upper uncertainty in f1E11 130-136 F7.5 --- e_f1E11 [3e-05/0.003] Lower uncertainty in f1E11 138-146 F9.7 --- f1E12 [4e-05/0.03] 1e^12^ accretion column stellar surface fraction covered 148-155 F8.6 --- E_f1E12 [7e-06/0.002] Upper uncertainty in f1E12 157-165 F9.7 --- e_f1E12 [2e-06/0.01] Lower uncertainty in f1E12 167-171 I5 K Tshock [4800/10542] Shock temperature 173-176 I4 K e_Tshock [14/1910] Uncertainty in Tshock -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- ID Object identifier 11- 14 F4.1 km/s vsini [3.2/18.4] Projected rotational velocity 16- 18 F3.1 km/s e_vsini [0.8/2] Uncertainty in vsini 20- 22 F3.1 d Per [4.3/7.1] Period 24- 27 F4.1 km/s Vel [8.3/23.5] Stellar rotational velocity 29- 31 F3.1 km/s e_Vel [0.5/2] Uncertainty in Vel 33- 36 F4.1 deg i [9.3/52.4]? Inclination 38- 40 F3.1 deg e_i [2/8]? Uncertainty in i -------------------------------------------------------------------------------- Byte-by-byte Description of file: table7.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- ID Object identifier 11- 14 I4 K T1E10 [3938/4675] 1e^10^ accretion column temperature 16- 16 I1 K e_T1E10 [1/2] Uncertainty in T1E10 18- 21 I4 K T1E11 [6310/6880] 1e^11^ accretion column temperature 23- 23 I1 K e_T1E11 [1/3] Uncertainty in T1E11 25- 29 I5 K T1E12 [10679/10973] 1e^12^ accretion column temperature 31- 31 I1 K e_T1E12 [2/3] Uncertainty in T1E12 33- 37 I5 K Tshock [4800/10542] Weighted-average shock temperature 39- 42 I4 K e_Tshock [14/1910] Uncertainty in Tshock (1) -------------------------------------------------------------------------------- Note (1): The error on Tshock comes from the propagated accretion column temperature and filling factor uncertainties. Since the filling factor uncertainties are not symmetric, the larger of the two uncertainties is used in the error propagation. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table8.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- ID Object identifier 11-14 F4.2 --- Mass/Rad [0.08/0.77] Ratio of stellar mass to radius 16-21 F6.4 10-8Msun/yr dM1E10 [0.0007/1] 10^10^ accretion column model accretion rate 23-28 F6.4 10-8Msun/yr E_dM1E10 [0.002/0.3] Upper uncertainty in Mdot1E10 30-35 F6.4 10-8Msun/yr e_dM1E10 [0.0004/0.4] Lower uncertainty in Mdot1E10 37-42 F6.4 10-8Msun/yr dM1E11 [0.001/2.1] 10^11^ accretion column model accretion rate 44-48 F5.3 10-8Msun/yr E_dM1E11 [0.01/0.7] Upper uncertainty in Mdot1E11 50-55 F6.4 10-8Msun/yr e_dM1E11 [0.001/0.6] Lower uncertainty in Mdot1E11 57-63 F7.4 10-8Msun/yr dM1E12 [0.025/15.1] 10^12^ accretion column model accretion rate 65-69 F5.3 10-8Msun/yr E_dM1E12 [0.004/2] Upper uncertainty in Mdot1E12 71-76 F6.4 10-8Msun/yr e_dM1E12 [0.001/5] Lower uncertainty in Mdot1E12 78-83 F6.3 10-8Msun/yr dMTot [0.529/17.2] Total accretion rate 85-89 F5.3 10-8Msun/yr E_dMTot [0.018/1.0] Upper uncertainty in MdotTot 91-95 F5.3 10-8Msun/yr e_dMTot [0.016/4.0] Lower uncertainty in MdotTot -------------------------------------------------------------------------------- Byte-by-byte Description of file: fig1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- ID Object identifier 11-14 F4.2 mag AV [0.05/1.43] V band extinction 16-19 F4.2 Rsun Rad [0.84/3.26] Stellar radius 21-29 F9.6 10-8Msun/yr dMass [0.52/17.3] Accretion rate 31-38 F8.6 --- f1E10 [4e-5/0.24] 1e^10^ accretion column stellar surface fraction covered 40-47 F8.6 --- f1E11 [4e-5/0.02] 1e^11^ accretion column stellar surface fraction covered 49-56 F8.6 --- f1E12 [4e-5/0.03] 1e^12^ accretion column stellar surface fraction covered 58-62 I5 K Tshock [4802/10650] Weighted-average shock temperature -------------------------------------------------------------------------------- Nomenclature Notes: History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Coralie Fix [CDS], 17-Jan-2023