J/AJ/170/19ivo://CDS.VizieR/J/AJ/170/19CDSLuhman K.L.2026-03-27T15:27:28Z2026-03-27T14:59:30ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frstar-forming-regionsdwarf-starsspectroscopyinfrared-astronomyvisible-astronomyphotometrymorgan-keenan-classificationlate-type-starsI present infrared spectroscopy of 37 brown dwarf candidates in the Upper Scorpius (Upper Sco) association, 35 of which are classified as young and cool, making them likely members. This sample includes many of the faintest spectroscopically confirmed members (K=16-17mag), which should have masses down to ~0.007-0.01M_{sun}_ for the range of ages in Upper Sco (7-14Myr). Using my updated membership catalog for Upper Sco, I have estimated the initial mass function (IMF) for a field in the center of the association that encompasses ~80% of the known members. I have derived IMFs in the same manner for previous membership samples in three other star-forming populations, consisting of IC 348, Taurus, and Chameleon I. When using logarithmic mass bins, the substellar IMFs for Upper Sco and the other young regions are roughly flat down to the completeness limits of ~0.01M_{sun}_. These IMFs are broadly similar to mass functions recently measured for the solar neighborhood. Finally, I have used W1-W2 colors to search for excess emission from circumstellar disks among the late-type objects in my new census of Upper Sco. I measure an excess fraction of 52/200 for members with spectral types of M6.25-M9.5, which is similar to results from previous membership catalogs. For the L-type members, it is difficult to detect the small W2 excess emission produced by typical disks around brown dwarfs because of the large uncertainties in spectral types, which preclude accurate estimates of the photospheric colors. Thus, W2 photometry provides poor constraints on the presence of disks for the L-type members of Upper Sco.2025AJ....170...19Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/170/19CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/117 : MK Classifications of Close Visual Binaries (Corbally, 1984)III/135A : Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989)II/240 : The DENIS database first release (Epchtein+, 1999)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)II/328 : AllWISE Data Release (Cutri+ 2013)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)II/367 : The VISTA Hemisphere Survey (VHS) catalog DR5 (McMahon+, 2020)I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)II/365 : The CatWISE2020 catalog (updated version 28-Jan-2021) (Marocco+, 2021)I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)J/A+A/333/619 : Upper Scorpius OB association Lithium survey (Preibisch+ 1998)J/AJ/117/354 : OB associations from Hipparcos (de Zeeuw+, 1999)J/ApJ/525/466 : Young low-mass stars and brown dwarfs in IC 348 (Luhman+, 1999)J/AJ/120/479 : Low-mass stars in the Upper Sco association (Ardila+, 2000)J/A+A/372/173 : ISOCAM observations of the rho Ophiuchi cloud (Bontemps+, 2001)J/A+A/378/116 : Classification & vsini of Vega-type and PMS stars (Mora+, 2001)J/AJ/121/1040 : PMS members of upper Scorpius OB association (Preibisch+, 2001)J/AJ/124/404 : Upper Scorpius OB assoc. Lithium surv. II. (Preibisch, 2002)J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)J/AJ/126/2971 : UBVRI photometry of 131 Herbig Ae/Be (Vieira+, 2003)J/ApJ/651/L49 : Upper Sco OB association IRAC observations (Carpenter+, 2006)J/MNRAS/373/95 : ZYJHK survey of Upper Sco association (Lodieu+, 2006)J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)J/AJ/131/3016 : Low-mass objects in Upper Scorpius (Slesnick+, 2006)J/A+A/460/695 : Search for Associations Containing Young stars (Torres+, 2006)J/MNRAS/374/372 : ZYJHK photometry in Upper Sco (Lodieu+, 2007)J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)J/ApJ/688/377 : Low-mass objects in Upper Scorpius. II. (Slesnick+, 2008)J/ApJ/699/1196 : JHKs light curves of 2MASS J05352184-0546085 (Gomez+, 2009)J/ApJ/703/1511 : Wide binaries in Taurus and Upper Sco (Kraus+, 2009)J/ApJ/712/925 : Transition circumstellar disks in Ophiuchus (Cieza+, 2010)J/ApJS/190/100 : NIR proper motion survey using 2MASS (Kirkpatrick+, 2010)J/MNRAS/418/1231 : New brown dwarfs in upper Sco (Dawson+, 2011)J/A+A/527/A24 : Spectra of low-mass stars in Upper Sco (Lodieu+, 2011)J/ApJ/746/154 : Improved kinematic plx for Sco-Cen members (Pecaut+, 2012)J/ApJ/754/30 : VISTA IR phot. of {sigma} Ori cluster (Pena Ramirez+, 2012)J/MNRAS/435/2474 : USco ZYJHK1K2 photometry and proper motions (Lodieu+, 2013)J/A+A/562/A127 : NIR integral field spec. of 15 M-L dwarfs (Bonnefoy+, 2014)J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)J/MNRAS/448/2737 : New PMS K/M Stars in Upper Scorpius (Rizzuto+, 2015)J/ApJS/225/10 : Kinematic analysis of M7-L8 dwarfs (Faherty+, 2016)J/MNRAS/461/794 : Scorpius-Centaurus K-Type Stars (Pecaut+, 2016)J/AJ/154/46 : Proper motions & phot. for members of Cha I (Esplin+, 2017)J/AJ/153/46 : Spectroscopy of candidate members in Taurus (Luhman+, 2017)J/AJ/156/75 : Circumstellar disks in the Upper Sco association (Esplin+, 2018)J/AJ/156/76 : New young stars and brown dwarfs in Upper Sco (Luhman+, 2018)J/AJ/158/54 : New Taurus memb. from stellar to planetary masses (Esplin+, 2019)J/AJ/159/282 : Membership in Ophiuchus & Upper Scorpius complex (Esplin+, 2020)J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)J/MNRAS/503/2265 : VISTA and Subaru/HSC obs. of Upper Scorpius (Lodieu+, 2021)J/A+A/664/A111 : Free-floating planet candidates in Upp Sco & Oph (Bouy+, 2022)J/AJ/163/24 : Stellar populations in the Sco-Cen complex (Luhman, 2022)J/AJ/163/25 : Circumst. disk populations in the Sco-Cen complex (Luhman, 2022)J/AJ/163/26 : Sp. of Sco-Cen memb & sp. classif in other clouds (Luhman+, 2022)J/other/NatAs/6.89 : Upper Scorpius members (Miret-Roig+, 2022)J/A+A/667/A163 : Upper Scorpius and Ophiuchus members (Miret-Roig+, 2022)J/ApJ/951/139 : W filter YSOs detect. VI. sigma Orionis members (Damian+, 2023)J/AJ/165/269 : TW Hya association candidate members (Luhman, 2023)J/A+A/685/A118 : Young (sub)stellar obj. X-Shooter spec (Almendros-Abad+, 2024)J/ApJS/271/55 : A full-sky 20pc census of stars & BDs (Kirkpatrick+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/170/19https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/170/19http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/170/19https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/170/19https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/170/19http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/170/19GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/170/19/table2 (Spectroscopic data for candidate members of Sco-Cen)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/170/19/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/170/19/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/170/19/table2?GETtext/xml+votable180.050000true238.1201-23.27067220.005555555555555556Cone search capability for table J/AJ/170/19/table3 (Adopted members of Upper Sco with spectral classifications at l=343-360 and b=10-30)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/170/19/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/170/19/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/170/19/table3?GETtext/xml+votable180.050000true233.04298-21.966913060.005555555555555556Cone search capability for table J/AJ/170/19/table5 (W2 excess flags for >M6 members of Upper Sco)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/170/19/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/170/19/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/170/19/table5?GETtext/xml+votable180.050000true233.96291194-20.3503550.0055555555555555564/2684 2686 2769 2772 5/10733 10750 11075 11085 11092 11094 11096-11097 11100 6/29320 29323 30722-30723 30732 42851 42854 42857 42862-42863 42901 42903 42906-42909 42911 42913 42918 42924 42929-42931 42938-42939 42941-42943 42962 42964 42967-42969 42972 42992 42994-42995 42998 43004 43006 44289 44293 44323 44325 44336-44338 44348-44350 44372-44373 44380-44382 44392 44396-44398 44404 44408-44410 44421 44433 44481 444853.830199579824256e-20 6.513807192489934e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/170/19?format=asciiOpticalInfrareddefaultJ/AJ/170/19/table2Spectroscopic data for candidate members of Sco-CenrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3? Gaia DR3 (I/355) source namemeta.idnullableNameSource name from UKIDSS (II/319) or VISTA VHS (II/367)meta.id;meta.maincharRAdeg? Gaia DR3 (I/355) right ascension (ICRS at Epoch 2016.0)degpos.eq.ranullableDEdeg? Gaia DR3 (I/355) declination (ICRS at Epoch 2016.0)degpos.eq.decnullableRAUdeg? Right ascension from UKIDSS (II/319) or VISTA VHS (II/367) (J2000)degpos.eq.ranullableFilesLink to the spectrum files in CSV format (added by CDS)meta.ref.urlcharSimbadNameSimbad column added by the CDSmeta.idcharnullableSpTypeSpectral type (1)src.spTypecharDEUdeg? Declination from UKIDSS (II/319) or VISTA VHS (II/367) (J2000)degpos.eq.decnullableYoungYoung? (2)meta.codecharInstrumentInstrument for spectroscopy (3)meta.id;instrcharDateDate of spectroscopytime.epochnullableSpSpectrummeta.ref.urlchar_RAPosition from Simbad (right ascension part)degpos.eq.ra;meta.mainnullable_DEPosition from Simbad (declination part)degpos.eq.dec;meta.mainnullableJ/AJ/170/19/table3Adopted members of Upper Sco with spectral classifications at l=343-360 and b=10-30SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaEDR3? Gaia EDR3 (I/350) source namemeta.idnullableUGCSUKIDSS Galactic Clusters Survey (II/319) source namemeta.idchar2MASS2MASS Point Source Catalog (II/246) source namemeta.id;meta.maincharNameOther source namemeta.idcharRA_ICRSRight ascension (ICRS)degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS)degpos.eq.dec;meta.mainRefReference for right ascension and declination (1)meta.ref;pos.eqcharSpTypeSpectral typesrc.spTypecharr_SpTypeSpectral type reference (2)meta.ref;src.spTypecharAdoptAdopted spectral typesrc.spTypecharJ/AJ/170/19/table5W2 excess flags for >M6 members of Upper ScoCatWISELink to AllWISE (II/328) and CatWISE2020 (II/365) catalogs data for sources within 1.5"meta.ref.urlintnullableSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaEDR3? Gaia EDR3 (I/350) source namemeta.idnullableUGCSUKIDSS Galactic Clusters Survey (II/319) source namemeta.id;meta.mainchar2MASS2MASS Point Source Catalog (II/246) source namemeta.idcharNameOther source namemeta.idcharRA_ICRSRight ascension (ICRS)degpos.eq.ra;meta.mainDE_ICRSDeclination (ICRS)degpos.eq.dec;meta.mainRefReference for right ascension and declination (1)meta.ref;pos.eqcharW1mag[10.9/16.6] WISE W1 magnitudemagphot.mag;em.IR.3-4umfloate_W1mag[0.01/0.06] Error in W1magmagstat.error;phot.mag;em.IR.3-4umfloatW2mag[10.7/16] WISE W2 magnitudemagphot.mag;em.IR.4-8umfloate_W2mag[9e-3/0.12] Error in W2magmagstat.error;phot.mag;em.IR.4-8umfloatExcExcess present in W2? (2)meta.codechar