14480( 5) - 18-Mar-2016 14:51:01 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14480 Version: 5 Check-in Time: 18-Mar-2016 14:51:01 STScI Edit Number: 2 Title Joint XMM-Newton and HST study of the magnetic weak-wind O-star HD 54879 ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Wolf-Rainer Hamann Universitat Potsdam Y CoI: Dr. Norberto Castro National Observatory of Athens N CoI: Dr. Luca Fossati Space Research Institute, Austrian Academy N of Sciences CoI: Dr. Swetlana Hubrig Astrophysikalisches Institut Potsdam N CoI: Dr. Thierry Morel Universite de Liege N CoI: Dr. Lida Oskinova Universitat Potsdam N CoI: Dr. Marcus Schoeller European Southern Observatory - Germany N CoI: Dr. Helge Todt Universitat Potsdam N ------------------------------------------------------------------------------------ Abstract Current massive-star astrophysics struggles with a number of urgent questions: what are the true mass-loss rates, what is the role of magnetic fields, how are X-rays produced? HD54879 provides an important laboratory to study these questions. While a strong magnetic field (2.1 , kG) has been recently detected in this star, it otherwise exhibits a normal spectrum of O9.7 main sequence type. We propose joint XMM and HST observations of HD54879. Analysis of the UV spectrum will establish the parameters of the cool stellar wind, while from the XMM data the hot plasma component will be studied. The new observations will establish a gauge for stellar wind theory and provide a template X-ray spectrum for magnetic massive stars with weak wind. ------------------------------------------------------------------------------------ Observations Description ------------------------ The immediate objective is to obtain the first UV spectrum of HD54879, using the HST STIS spectrograph. This will be the first UV spectrum of a non-peculiar late-type O dwarf with confirmed magnetic field. From these data, we want to infer the stellar wind parameters, especially the mass-loss rate and the wind velocity. The requested observations shall be performed with the E140M echelle grating centered at 1425Ang, and recorded by the FUV MAMA detector. The high spectral resolution is needed to separate the wind lines from the photospheric iron line forest. We aim at a S/N ratio of about 50 at the C IV doublet (~1500Ang). We uploaded the predicted model flux to the HST exposure time calculator (STIS.sp.639603), and obtained an exposure time of 42min. With the small 0.1'' x0.03'' aperture, the total count rate stays below the MAMA bright limit by a factor of two, which is safe since the source is not variable. ------------------------------------------------------------------------------------ 14480( 5) - 18-Mar-2016 14:51:01 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD-54879 STAR, B0-B2 V-IV RA=07H10M8.1495S +/- 0.006", J2000 V = 7.65 DEC=-11D48'9.84" +/- 0.006" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -1.4711025923324985E-4 8.100000000000001E-4 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 14480( 5) - 18-Mar-2016 14:51:01 - [ 3] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD-54879 STIS/CCD ACQ F25ND3 MIRROR 1 4 S (4 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 HD-54879 STIS/CCD ACQ/PEA 0.3X0.05N MIRROR 1 2 S (2 S) K D ------------------------------------------------------------------------------------------------------------------------------------ 3 HD-54879 STIS/CCD ACQ/PEA 0.1X0.03 G430L 4300 1 0.1 S (0.1 K S) ------------------------------------------------------------------------------------------------------------------------------------ 4 HD-54879 STIS/FUV ACCUM 0.1X0.03 E140M 1425 1 580 S -MAMA see below (383 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 HD-54879 STIS/FUV ACCUM 0.1X0.03 E140M 1425 1 580 S -MAMA see below (383 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 HD-54879 STIS/FUV ACCUM 0.1X0.03 E140M 1425 1 550 S -MAMA see below (353 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ HD-54879 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A HD-54879 2 STIS/CCD ACQ/PEA 0.3X0.05 MIRROR none none none none 1 N/A K ND HD-54879 3 STIS/CCD ACQ/PEA 0.1X0.03 G430L 4300 none none none none 1 N/A K HD-54879 4 STIS/FUV ACCUM 0.1X0.03 E140M 1425 none none none none 1 383.0 S -MAMA HD-54879 5 STIS/FUV ACCUM 0.1X0.03 E140M 1425 none none none none 1 383.0 S -MAMA HD-54879 6 STIS/FUV ACCUM 0.1X0.03 E140M 1425 none none none none 1 353.0 S -MAMA 14480( 5) - 18-Mar-2016 14:51:01 - [ 4] Summary Form for Proposal 14480 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 0.1X0.03, 0.3X0.05ND, F25ND3 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements E140M, G430L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD-54879 ------------------------------------------------------------------------------------------------------------------------------------