LAMORIXMM ivo://nasa.heasarc/lamorixmm NASA/GSFC HEASARC Franciosini, Sacco 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The authors studied the X-ray properties of the young (~1-8M yr) open cluster around the hot (O8 III) star Lambda Ori and compared them with those of the similarly-aged Sigma Ori cluster in order to investigate the possible effects of the different ambient environments. They analyzed an XMM-Newton observation of the cluster using EPIC imaging and low-resolution spectral data. They studied the variability of the detected sources, and performed a spectral analysis of the brightest sources in the field using multi-temperature models. The authors detected 167 X-ray sources above a 5-sigma detection threshold the properties of which are listed in this table, of which 58 are identified with known cluster members and candidates, from massive stars down to low-mass stars with spectral types of ~ M5.5. Another 23 sources were identified with new possible photometric candidates. Late-type stars have a median log L<sub>X</sub>/L<sub>bol</sub> ~ -3.3, close to the saturation limit. Variability was observed in ~ 35% of late-type members or candidates, including six flaring sources. The emission from the central hot star Lambda Ori is dominated by plasma at 0.2 - 0.3 keV, with a weaker component at 0.7 keV, consistent with a wind origin. The coronae of late-type stars can be described by two plasma components with temperatures T<sub>1</sub> ~ 0.3-0.8 keV and T<sub>2</sub> ~ 0.8-3 keV, and subsolar abundances Z ~ 0.1-0.3 Z<sub>sun</sub>, similar to what is found in other star-forming regions and associations. No significant difference was observed between stars with and without circumstellar discs, although the smallness of the sample of stars with discs and accretion does not definitive conclusions to be drawn. The authors concluded that the X-ray properties of Lambda Ori late-type stars are comparable to those of the coeval Sigma Ori cluster, suggesting that stellar activity in Lambda Ori has not been significantly affected by the different ambient environment. The lambda Ori cluster was observed by XMM-Newton from 20:46 UT on September 28, 2006 to 12:23 UT on September 29, 2006 (Obs. ID 0402050101), for a total duration of 56ks, using both the EPIC MOS and PN cameras and the RGS instruments. The EPIC cameras were operated in full frame mode with the thick filter. This table was created by the HEASARC in November 2011 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/530/A150">CDS Catalog J/A+A/530/A150</a> files tablea1.dat ('X-ray sources detected in the Lambda Ori Cluster'), table1,dat ('X-ray and optical properties of sources identified with known cluster members and candidates') and table2.dat ('X-ray sources identified with possible new cluster candidates'). It does not include the objects listed in tablea2.dat ('3-sigma upper limits and optical properties of undetected cluster members and candidates'). This is a service provided by NASA HEASARC . 2011A&A...530A.150F https://heasarc.gsfc.nasa.gov/W3Browse/all/lamorixmm.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=lamorixmm& GET text/xml 180 99999 true 83.72170833 9.71155556 0.0166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=lamorixmm GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_lamorixmm&Action=More+Options&Action=Parameter+Search&ConeAdd=1 XMM-NEWTON 0.0166666666666667 X-ray public lamorixmm Lambda Orionis Cluster XMM-Newton X-Ray Point Source Catalog source_number Sequential Identification Number for Each Source in Catalog meta.id;src short nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable count_rate MOS-Equivalent Count Rates in the 0.3-7.8keV Band ct/s phot.count;em.X-ray double nullable count_rate_error RMS Uncertainty in Count Rate ct/s stat.error;phot.count;em.X-ray double nullable alt_name Identification meta.id.assoc char nullable off_set Offset Between X-Ray Source and Optical Identification arcsec pos.angDistance double nullable rmag R Magnitude mag phot.mag;em.opt.R double nullable disk_type Disk Classification src.class char nullable notes Notes for Identification meta.note char nullable mass_2 Mass Solar_Mass phys.mass double nullable notes_2 Notes for Alternative Identification meta.note char nullable lii Galactic Longitude degree pos.galactic.lon double nullable spect_type MK Spectral Type src.spType char nullable class Browse Object Classification src.class short nullable imag I Magnitude mag phot.mag;em.opt.I double nullable mass Mass Solar_Mass phys.mass double nullable off_axis Off-Axis Separation arcmin instr.offset double nullable hmag H Magnitude mag phot.mag;em.IR.H double nullable log_lx_lbol X-Ray-to-Bolometric Luminosity Ratio phys.luminosity;arith.ratio double nullable ks_mag_2 K_s Magnitude mag phot.mag;em.IR.K double nullable alt_name_2 Alternative Identification meta.id char nullable snr Detection Significance stat.snr double nullable log_lx_2 X-Ray Luminosity in the 0.3-7.8keV Band assuming d=400pc log(erg/s) phys.luminosity;em.X-ray double nullable membership_flag Flag [sP] Indicates Membership Code meta.code char nullable bii Galactic Latitude degree pos.galactic.lat double nullable name Source Designation meta.id;meta.main char nullable offset_2 Offset Between X-Ray Source and Alternative Optical Identification arcsec pos.angDistance double nullable log_lx_lbol_2 X-Ray-to-Bolometric Luminosity Ratio phys.luminosity;arith.ratio double nullable note_alt_name Flag [e] Indicates Individual Note Concerning Identification meta.note char nullable vmag V Magnitude mag phot.mag;em.opt.V double nullable ks_mag K_s Magnitude mag phot.mag;em.IR.J double nullable imag_flag Flag [S] Indicates Note Concerning I Magnitude meta.code;phot.mag;em.opt.I char nullable hmag_2 H Magnitude mag phot.mag;em.IR.H double nullable jmag J Magnitude mag phot.mag;em.IR.J double nullable log_lx X-Ray Luminosity in the 0.3-8keV Band log(erg/s) phys.luminosity;em.X-ray double nullable rmag_flag Flag [S] Indicates Note Concerning R Magnitude meta.code;phot.mag;em.opt.R char nullable log_lx_flag Flag [S] Indicates Value Derived from Spectral Fits meta.code;phys.luminosity;em.X-ray char nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable