Accretion in the Rho-Oph pre-main sequence stars

Abstract

The aim of this paper is to provide a measurement of the mass accretion rate in a large, complete sample of objects in the core of the star forming region Rho-Oph. The sample includes most of the objects (104 out of 111) with evidence of a circumstellar disk from mid-infrared photometry; it covers a stellar mass range from about 0.03 to 3 Msun and it is complete to a limiting mass of ~0.05 Msun. We used J and K-band spectra to derive the mass accretion rate of each object from the intensity of the hydrogen recombination lines, Pab or Brg. For comparison, we also obtained similar spectra of 35 diskless objects. The results show that emission in these lines is only seen in stars with disks, and can be used as an indicator of accretion. However, the converse does not hold, as about 50% of our disk objects do not have detectable line emission. The measured accretion rates show a strong correlation with the mass of the central object (Macc ~ Mstar^1.8+-0.2) and a large spread, of two orders of magnitude at least, for any interval of Mstar. A comparison with existing data for Taurus shows that the objects in the two regions have similar behaviour, at least for objects more massive than ~0.1Msun. The implications of these results are briefly discussed.

A&A in press, 16 pages including tables, 5 figures

References in corpus (18)

• Very Low Mass Stars and Brown Dwarfs in Taurus-Auriga
• The Origin of T Tauri X-ray Emission: New Insights from the Chandra Orion Ultradeep Project
• Observational Constraints on the Formation and Evolution of Binary Stars
• Accretion in Young Stellar/Substellar Objects
• Accretion in Brown Dwarfs: an Infrared View
• Evolution of protoplanetary disks: Constraints from DM Tauri and GM Aurigae
• ISOCAM observations of the rho Ophiuchi cloud: Luminosity and mass functions of the pre-main sequence embedded cluster
• Low-Mass Star Formation and the Initial Mass Function in the Rho Ophiuchi Cloud Core
• Measuring Accretion in Young Substellar Objects: Approaching the Planetary Mass Regime
• Optical Spectroscopy of the Surface Population of the rho Ophiuchi Molecular Cloud: The First Wave of Star Formation
• Exploring Brown Dwarf Disks in rho Oph
• A Multiplicity Survey of the Rho Ophiuchi Molecular Clouds
• Evidence for J and H-band excess in classical T Tauri stars and the implications for disk structure and estimated ages
• The stellar mass-accretion rate relation in T Tauri stars and brown dwarfs
• Near-Infrared Classification Spectroscopy: J-Band Spectra of Fundamental MK Standards
• A Search for Close Binaries in the Rho Ophiuchus Star-Forming Region
• A Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the Rho Ophiuchi Cloud Core
• Stellar Properties of Pre-Main Sequence Stars from High Resolution Near-IR Spectra

Cited by in corpus (256)

• The Disk Substructures at High Angular Resolution Project (DSHARP): I. Motivation, Sample, Calibration, and Overview
• Protoplanetary Disk Structures in Ophiuchus
• Resolved Images of Large Cavities in Protoplanetary Transition Disks
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• High Resolution Submillimeter Constraints on Circumstellar Disk Structure
• Protoplanetary Disk Structures in Ophiuchus II: Extension to Fainter Sources
• X-Shooter spectroscopy of young stellar objects: IV -- Accretion in low-mass stars and sub-stellar objects in Lupus
• UV excess measures of accretion onto young very low-mass stars and brown dwarfs
• Radiation-Hydrodynamic Models of X-Ray & EUV Photoevaporating Protoplanetary Discs
• Spiral Density Waves in a Young Protoplanetary Disk
• A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus
• On the theory of disc photoevaporation
• Structure and evolution of pre-main sequence circumstellar disks
• Accretion-Driven Turbulence as Universal Process: Galaxies, Molecular Clouds, and Protostellar Disks
• Star and protoplanetary disk properties in Orion's suburbs
• Time-Evolution of Viscous Circumstellar Disks due to Photoevaporation by FUV, EUV and X-ray Radiation from the Central Star
• Accretion Rates in Herbig Ae stars
• Dust grain growth in rho-Ophiuchi protoplanetary disks
• A Spitzer survey of mid-infrared molecular emission from protoplanetary disks I: Detection rates
• A spectroscopic survey of Herbig Ae/Be stars with X-Shooter I: Stellar parameters and accretion rates
• The Formation and Early Evolution of Low-mass Stars and Brown Dwarfs
• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• Transitional Disks as Signposts of Young, Multiplanet Systems
• LkH$\alpha$ 330: Evidence for dust clearing through resolved submillimeter imaging
• A decreased probability of habitable planet formation around low-mass stars
• Evidence for dust clearing through resolved submillimeter imaging
• A Spitzer Survey of Mid-Infrared Molecular Emission from Protoplanetary Disks II: Correlations and LTE Models
• Evidence for a correlation between mass accretion rates onto young stars and the mass of their protoplanetary disks
• Magnetorotational Instability Driven Accretion in Protoplanetary Disks
• X-shooter spectroscopy of young stellar objects: I - Mass accretion rates of low-mass T Tauri stars in σOrionis
• Dust depleted inner disks in a large sample of transition disks through long-baseline ALMA observations
• The structure and dynamics of molecular gas in planet-forming zones: A CRIRES spectro-astrometric survey
• Accretion disks in luminous young stellar objects
• X-Shooter study of accretion in Chamaeleon I: II. A steeper increase of accretion with stellar mass for very low mass stars?
• ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet
• Gas density drops inside dust cavities of transitional disks around young stars observed with ALMA
• On the gas content of transitional disks: a VLT/X-Shooter study of accretion and winds
• X-Shooter spectroscopy of young stellar objects: II. Impact of chromospheric emission on accretion rate estimates
• Disk Evolution in the three Nearby Star-Forming Regions of Taurus, Chamaeleon, and Ophiuchus
• The Nature of Transition Circumstellar Disks I. The Ophiuchus Molecular Cloud
• Scaling Relations Associated with Millimeter Continuum Sizes in Protoplanetary Disks
• Mapping accretion and its variability in the young open cluster NGC 2264: a study based on u-band photometry
• Accretion rates and accretion tracers of Herbig Ae/Be stars
• X-Shooter study of accretion in Chamaeleon I
• Detection of [Ne II] Emission from Young Circumstellar Disks
• Metallicity, planet formation, and disc lifetimes
• Temperaments of young stars: Rapid mass-accretion rate changes in T Tauri and Herbig Ae stars
• The Ophiuchus DIsc Survey Employing ALMA (ODISEA)-III: the evolution of substructures in massive discs at 3-5 au resolution
• Measuring Protoplanetary Disk Accretion with H I Pf-beta
• Protoplanetary Disk Masses from Stars to Brown Dwarfs
• Super-Earth masses sculpted by pebble isolation around stars of different masses
• Multiple Gaps in the Disk of the Class I Protostar GY 91
• A New Look at T Tauri Star Forbidden Lines: MHD Driven Winds from the Inner Disk
• Young Stellar Objects in Lynds 1641: Disks, Accretion, and Star Formation History
• Two new HATNet hot Jupiters around A stars, and the first glimpse at the occurrence rate of hot Jupiters from TESS
• Accretion onto Planetary Mass Companions of Low-Mass Young Stars
• A Disk Around the Planetary-Mass Companion GSC 06214-00210 b: Clues About the Formation of Gas Giants on Wide Orbits
• Infall-Driven Protostellar Accretion and the Solution to the Luminosity Problem
• Stellar Mass Dependent Disk Dispersal
• Accretion in protoplanetary disks: the imprint of core properties
• The accretion rates and mechanisms of Herbig Ae/Be stars
• HST measures of Mass Accretion Rates in the Orion Nebula Cluster
• A systematic survey for eruptive young stellar objects using mid-infrared photometry
• Homogeneous Analysis of the Dust Morphology of Transition Disks Observed with ALMA: Investigating dust trapping and the origin of the cavities
• T Tauri candidates and accretion rates using IPHAS: method and application to IC1396
• Single peaked CO emission line profiles from the inner regions of protoplanetary disks
• Assembling the Building Blocks of Giant Planets around Intermediate Mass Stars
• Brown dwarf disks with ALMA: evidence for truncated dust disks in Ophiuchus
• The structure of disks around intermediate-mass young stars from mid-infrared interferometry. Evidence for a population of group II disks with gaps
• Protoplanetary disc `isochrones' and the evolution of discs in the $\dot{M}-M_{\mathrm{d}}$ plane
• On the origin of [NeII] 12.81 micron emission from pre-main sequence stars: Disks, jets, and accretion
• Measuring tiny mass accretion rates onto young brown dwarfs
• The Lifetime of Protoplanetary Disks in a Low-Metallicity Environment
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds: VII. Ophiuchus Observed with MIPS
• Constraints from Dust Mass and Mass Accretion Rate Measurements on Angular Momentum Transport in Protoplanetary Disks
• On the origin of the spiral morphology in the Elias 2-27 circumstellar disc
• Photometric determination of the mass accretion rates of pre-main sequence stars. I. Method and application to the SN1987A field
• Direct Imaging of Bridged Twin Protoplanetary Disks in a Young Multiple Star
• Observations of Solids in Protoplanetary Disks
• Probing stellar accretion with mid-infrared hydrogen lines
• The protoplanetary disk population in the rho-Ophiuchi region L1688 and the time evolution of Class II YSOs
• The (w)hole survey: an unbiased sample study of transition disk candidates based on Spitzer catalogs
• Magnetocentrifugally Driven Flows from Young Stars and Disks. VI. Accretion with a Multipole Stellar Field
• Demographics of Transition Discs in Ophiuchus and Taurus
• The role of disc self-gravity in the formation of protostars and protostellar discs
• Mass Accretion onto T Tauri Stars
• Spin Evolution of Accreting Young Stars. I. Effect of Magnetic Star-Disk Coupling
• PENELLOPE: the ESO data legacy program to complement the Hubble UV Legacy Library of Young Stars (ULLYSES) I. Survey presentation and accretion properties of Orion OB1 and $\sigma$-Orionis
• Dusty Disks around White Dwarfs I: Origin of Debris Disks
• KELT-17b: A hot-Jupiter transiting an A-star in a misaligned orbit detected with Doppler tomography
• U-band study of the accretion properties in the sigma Ori star-forming region
• Protoplanetary Disk Sizes and Angular Momentum Transport
• Classical T Tauri-like Outflow Activity in the Brown Dwarf Mass Regime
• Dippers and Dusty Disks Edges: A Unified Model
• High resolution spectroscopy of Ne II emission from young stellar objects
• Multi-wavelength diagnostics of accretion in an X-ray selected sample of CTTSs
• Mapping H-band Scattered Light Emission in the Mysterious SR21 Transitional Disk
• A continuum of accretion burst behavior in young stars observed by K2
• A Census of the Stellar Populations in the Sco-Cen Complex
• A Tale of Planet Formation: From Dust to Planets
• `Tail-end' Bondi-Hoyle accretion in young star clusters: Implications for disks, planets, and stars
• Photometric determination of the mass accretion rates of pre-main sequence stars. II. NGC346 in the Small Magellanic Cloud
• X-Shooter study of accretion in $\rho$-Ophiucus: very low-mass stars and brown dwarfs
• Relation between the luminosity of young stellar objects and their circumstellar environment
• The onset of X-ray emission in young stellar objects: a Chandra observation of the Serpens star-forming region
• POISSON project - II - A multi-wavelength spectroscopic and photometric survey of young protostars in L 1641
• LAMP: The Long-term Accretion Monitoring Program of T Tauri stars in Chamaeleon-I
• The Separation/Period Gap in the Distribution of Extrasolar Planets around Stars with Masses M >= 1.2 Msolar
• Transitional disks and their origins: an infrared spectroscopic survey of Orion A
• New Constraints From Dust Lines On The Surface Densities Of Protoplanetary Disks
• Emission Line Variability of the Accreting Young Brown Dwarf 2MASSW J1207334-393254: From Hours to Years
• Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates
• POISSON project - I - Emission lines as accretion tracers in young stellar objects: results from observations of Chamaeleon I and II sources
• V1094 Sco: a rare giant multi-ringed disk around a T Tauri star
• The Chamaeleon II low-mass star-forming region: radial velocities, elemental abundances, and accretion properties
• Mass accretion rates in self-regulated disks of T Tauri stars
• Disks and Outflows in CO Rovibrational Emission from Embedded, Low-Mass Young Stellar Objects
• Deep near-IR variability survey of pre-main-sequence stars in Rho Ophiuchi
• Sub-stellar Companions and Stellar Multiplicity in the Taurus Star-Forming Region
• The TEXES Survey For H2 Emission From Protoplanetary Disks
• On the mass accretion rate and infrared excess in Herbig Ae/Be Stars
• The low-mass population of the Rho Ophiuchi molecular cloud
• The outburst of an embedded low-mass YSO in L1641
• WL 17: A Young Embedded Transition Disk
• KMOS study of the mass accretion rate from Class I to Class II in NGC 1333
• Near 3:2 and 2:1 mean motion resonances formation in the systems observed by Kepler
• The Bimodality of Accretion In T Tauri Stars and Brown Dwarfs
• Periodic and Aperoidic Variability in the Molecular Cloud ρOphiuchus
• The hybrid disks: a search and study to better understand evolution of disks
• POISSON project - III - Investigating the evolution of the mass accretion rate
• HAT-P-67b: An Extremely Low Density Saturn Transiting an F-Subgiant Confirmed via Doppler Tomography
• Search for associations containing young stars (SACY) VIII. An updated census of spectroscopic binary systems showing hints of non-universal multiplicity among these associations
• An ALMA and MagAO Study of the Substellar Companion GQ Lup B
• Pre-main sequence stars in the Cepheus flare region
• A Multi-Wavelength Analysis of Dust and Gas in the SR 24S Transition Disk
• Resolving structure of the disk around HD100546 at 7 mm with ATCA
• A Survey for New Stars and Brown Dwarfs in the Ophiuchus Star-forming Complex
• The Peculiar Periodic YSO WL 4 in Rho Ophiuchus
• Is the spiral morphology of the Elias 2-27 circumstellar disc due to gravitational instability?
• On the origin of the correlations between the accretion luminosity and emission line luminosities in pre-main sequence stars
• The Mdot - M* relation of pre-main sequence stars: a consequence of X-ray driven disc evolution
• ALMA observations of Elias 2-24: a protoplanetary disk with multiple gaps in the Ophiuchus Molecular Cloud
• 2MASS 22344161+4041387AB: A Wide, Young, Accreting, Low-mass Binary in the LkHa233 Group
• Are Elias 2-27's spiral arms driven by self-gravity, or by a companion? A comparative spiral morphology study
• Physical Conditions of Accreting Gas in T Tauri Star Systems
• Photometric determination of the mass accretion rate of pre-main sequence stars. IV. Recent star formation in NGC 602
• Mass accretion to young stars triggered by flaring activity in circumstellar disks
• Accretion properties of T Tauri stars in sigma Ori
• Classical T Tauri stars with VPHAS$+$: I: H$\alpha$ and $u$-band accretion rates in the Lagoon Nebula M8
• Accretion bursts in young stars driven by cluster environment
• X-ray view of IC348 in the light of an updated cluster census
• Predicting the Configuration of Planetary System: KOI-152 Observed by Kepler
• Photometric determination of the mass accretion rates of pre-main sequence stars. III. Results in the Large Magellanic Cloud
• Accretion signatures in the X-shooter spectrum of the substellar companion to SR12
• Herbig Stars: A Quarter Century of Progress
• Substellar Objects in Nearby Young Clusters (SONYC) II: The Brown Dwarf Population of Rho Ophiuchi
• The Preservation of Super Earths and the Emergence of Gas Giants after Their Progenitor Cores have Entered the Pebble Isolation Phase
• Interpreting Near Infrared Hydrogen Line Ratios in T Tauri Stars
• A high resolution mid-infrared survey of water emission from protoplanetary disks
• Strongly misaligned triple system in SR 24 revealed by ALMA
• Short and long term near-infrared spectroscopic variability of eruptive protostars from VVV
• Accretion in rho-Ophiuchi brown dwarfs: infrared hydrogen line ratios
• Photometric determination of the mass accretion rates of pre-main sequence stars. V. Recent star formation in the 30 Dor nebula
• GIARPS High-resolution Observations of T Tauri stars (GHOsT). III. A pilot study of stellar and accretion properties
• Growth of Jupiter: Formation in Disks of Gas and Solids and Evolution to the Present Epoch
• Submillimeter Array Observations of the RX J1633.9-2442 Transition Disk: Evidence for Multiple Planets in the Making
• Medium resolution near-infrared spectroscopy of Massive Young Stellar Objects
• The influence of the environment on the spin evolution of low-mass stars. I. External photoevaporation of circumstellar disks
• The Evolution of Circumstellar Disks in Ophiuchus Binaries
• Results from Droxo. I. The variability of fluorescent Fe 6.4 keV emission in the young star Elias 29: High-energy electrons in the star's accretion tubes?
• Results from DROXO. III. Observation, source list and X-ray properties of sources detected in the "Deep Rho Ophiuchi XMM-Newton Observation"
• Long-term Evolution of Photoevaporating Protoplanetary Disks
• Spatially Resolved Mid-IR Imaging of the SR 21 Transition Disk
• Testing external photoevaporation in the $\sigma$-Orionis cluster with spectroscopy and disk mass measurements
• Observational diagnostics of gas in protoplanetary disks
• Forming Habitable Planets around Dwarf Stars: Application to OGLE-06-109L
• Near Infrared Observations of GQ Lup b Using the Gemini Integral Field Spectrograph NIFS
• An Observational Study for Grain Dynamics in the AS 209 Disk with Submillimeter Polarization
• Protoplanetary dust porosity and FU Orionis Outbursts: Solving the mystery of Earth's missing volatiles
• Disc evolution and the relationship between $L_{\mathrm{acc}}$ and $L_{\ast }$ in T Tauri stars
• LBT/LUCIFER near-infrared spectroscopy of PV Cephei. An outbursting young stellar object with an asymmetric jet
• The Spitzer Survey of Interstellar Clouds in the Gould Belt. IV. Lupus V and VI Observed with IRAC and MIPS
• Determining Dust Properties in Protoplanetary Disks: SED-derived Masses and Settling With ALMA
• Results from DROXO. II. - [Ne II] and X-ray emission from Rho Ophiuchi young stellar objects
• Proper motion survey and kinematic analysis of the Rho Ophiuchi embedded cluster
• What Sets the Radial Locations of Warm Debris Disks?
• An Inner Disk in the Large Gap of the Transition Disk SR 24S
• Strong Biases in Estimating the Time Dependence of Mass Accretion Rates in Young Stars
• Sejong Open Cluster Survey (SOS). II. IC 1848 Cluster in the H II Region W5 West
• Pre-main sequence accretion in the low metallicity Galactic star-forming region Sh 2-284
• Sejong Open Cluster Survey (SOS). III. The Young Open Cluster NGC 1893 in the H II Region W8
• Testing the models of X-ray driven photoevaporation with accreting stars in the Orion Nebula Cluster
• Near Mean-motion Resonances in the Systems Observed by Kepler: Affected by Mass Accretion and Type I Migration
• X-Shooter spectroscopy of young stellar objects - VI - HI line decrements
• The enigmatic young brown dwarf binary FU Tau: accretion and activity
• Migration and Growth of Protoplanetary Embryos III: Mass and Metallicity Dependence for FGKM main-sequence stars
• Evidence for early disk-locking among low-mass members of the Orion Nebula Cluster
• The Structure of the DoAr 25 Circumstellar Disk
• On the time evolution of the $M_{\mathrm{d}}-M_{\star }$ and $\dot{M}-M_{\star }$ correlations for protoplanetary discs: the viscous timescale increases with stellar mass
• Potential Drivers of Mid-Infrared Variability in Young Stars: testing physical models with multi-epoch near-infrared spectra of YSOs in ρ Oph
• On the properties of discs around accreting brown dwarfs
• A sub-AU outwardly truncated accretion disk around a classical T Tauri star
• Constraining accretion signatures of exoplanets in the TW Hya transitional disk
• Evolutionary tracks of massive stars during formation
• Photo-reverberation Mapping of a Protoplanetary Accretion Disk around a T Tauri Star
• Resonances of Multiple Exoplanets and Implications for Their Formation
• Finding proto-spectroscopic binaries: Precise multi-epoch radial velocities of 7 protostars in rho-Ophiuchus
• S and VV Corona Australis: Spectroscopic Variability in Two Young Binary Star Systems
• Accretion onto a binary from a polar circumbinary disc
• Investigating 2MASS J06593158-0405277: a FUor burst in a triple system?
• Spectroscopy and Linear Spectropolarimetry of the early Herbig Be Stars PDS 27 and PDS 37
• On the accretion properties of young stellar objects in the L1615/L1616 cometary cloud
• Spatially resolved H_2 emission from a very low-mass star
• Residual Gas & Dust Around Transition Objects and Weak T Tauri Stars
• A deep X-ray view of the Class I YSO Elias 29 with XMM-Newton and NuSTAR
• Astrophysics in 2006
• Constraints on the height of the inner disk rim in pre-main-sequence stars
• ALMA observations of the early stages of substellar formation in the Lupus 1 and 3 molecular clouds
• Accretion variability in RU Lup
• Probing the Temperature Structure of Optically Thick Disks Using Polarized Emission of Aligned Grains
• Photometric determination of the mass accretion rates of pre-main sequence stars. VII. The low-density cluster NGC 376 in the Small Magellanic Cloud
• Classical T-Tauri stars with VPHAS+: II: NGC 6383 in Sh 2-012
• X-ray deficiency on strong accreting T Tauri stars - Comparing Orion with Taurus
• Modeling Planetary System Formation with N-Body Simulations: Role of Gas Disk and Statistics Comparing to Observations
• Optical and Near-Infrared Excesses are Correlated in T Tauri Stars
• The Mid-Infrared Polarization of the Herbig Ae Star WL 16: An Interstellar Origin?
• SUBARU Near-Infrared Imaging Polarimetry of Misaligned Disks Around The SR24 Hierarchical Triple System
• On the lifetime of discs around late type stars
• Understanding the angular momentum evolution of T Tauri and Herbig Ae/Be stars
• The intermediate-mass star-forming region Lynds 1340. An optical view
• A long-lasting quiescence phase of the eruptive variable V1118 Ori
• How Flow Isolation May Set the Mass Scale for Super-Earth Planets
• A multiwavelength view of the protostellar binary IRAS04325+2402: a case for turbulent fragmentation
• The young star population of L1188
• Inner warm disk of ESO H$\alpha$ 279A revealed by NA I and CO overtone emission lines
• Accretion bursts in young intermediate-mass stars make planet formation challenging
• The nature of the embedded intermediate-mass T Tauri star DK Cha
• Disks, accretion and outflows of brown dwarfs
• Probing accretion and stellar properties in the Orion Nebula with VLT/X-Shooter
• Evolution of a Viscous Protoplanetary Disk with Convectively Unstable Regions. II. Accretion Regimes and Long-Term Dynamics
• The curious case of PDS 11: a nearby, >10 Myr old, classical T Tauri binary system
• Angular momentum transport via gravitational instability in the Elias 2-27 disc
• Star Formation in the Starburst Cluster in NGC 3603
• Infrared Search for Young Brown Dwarf Companions around Young Stellar Objects in the rho Ophiucus Molecular Cloud and the Serpens Molecular Cloud
• Estimation of Stellar Parameters and Mass Accretion Rate of Classical T Tauri Stars from LAMOST DR6
• Improving Accretion Diagnostics for Young Stellar Objects with Mid-infrared Hydrogen lines from JWST/MIRI
• The accretion luminosity of Class I protostars
• Occurrence rates of accreting companions from a new method for computing emission-line survey sensitivity: application to the H-alpha Giant Accreting Protoplanet Survey
• High CO/H2 ratios supports an exocometary origin for a CO-rich debris disk
• HI line analysis of Herbig Ae/Be stars using X-Shooter spectra
• Planet Formation Around M-dwarfs: From Young Disks to Planets
• Science with MATISSE
• Identification and spectroscopic characterization of 128 new Herbig stars
• Evolution of the Accretion Rate of Young Intermediate Mass Stars: Implications for Disk Evolution and Planet Formation
• Keck Observations in the INfrared of Taurus and $\rho$ Oph Exoplanets And Ultracool dwarfs (KOINTREAU) II: Two Young Bound Companions to Ophiuchus Stars