9576( 5) - 02/06/02 11:55 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9576 Version: 5 Check-in Date: 06-Feb-2002 11:54:42 1.Proposal Title: Establishing an observational baseline for the newly discovered peculiar variable in Monoceros ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO/DD 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Thomas Rauch Universitat Tubingen, Institut fur Astronomie & Astrophysik CoI: M. Asplund Uppsala Astronomical Observatory N CoI: H.-U. Kaeufl European Southern Observatory N CoI: F. Kerber Space Telescope European Coordinating Y Facility CoI: M. Rosa Space Telescope European Coordinating N Facility CoI: R. Williams Space Telescope Science Institute N ------------------------------------------------------------------------------------ 5. Abstract We propose UV spectroscopy using STIS of a newly discovered (Jan 6th) peculiar variable in Monoceros in order to determine its spectral class and the physical parameters of the star. This will establish a baseline for monitoring the future evolution of this object. Low resolution spectra of this possible nova of 10th mag were obtained on Jan 8th and 9th and exhibit a reddened continuum plus a wealth of absorption features and four prominent emission lines exhibiting P-Cyg profiles. Three of these can be identified with Ba II (multiplet 2) at 5855, 6142, and 6497A. In addition, strong Na I 5897A and weak Halpha emission (equivalent width 1A, FWHM 200 km/sec) are present and exhibit P-Cyg profiles. Other features include many absorption lines of Fe II in the region 5000-5600A, O I 7774A, and Ca II 8598, 8542A. Evidently the spectrum is highly unusual for a nova. The mere existence of Ba emission lines tells us that this is a very special but highly evolved star and the object has been suggested to be a peculiar slow nova or a post-AGB star which has just suffered a final helium flash. Thus, it might be similar to Sakurai's object. It would then offer the unique opportunity to observe the very early phases of a final helium flash, something which could not be achieved in the case of Sakurai's object. ------------------------------------------------------------------------------------ 9576( 5) - 02/06/02 11:55 - [ 2] Observations Description ------------------------ We plan to perform long-slit spectroscopy of the newly discovered peculiar variable in Monoceros in the NUV (G230LB) configuration. This covers the range 1680--3060 A and enables the determination of the spectral type and the stellar parameters. The determination of the luminosity class is essential, because of the presently still unknown nature of this object. Recently the object brightened by more than 3 mags to mV = 7. The observation can be performed during one orbit. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- This is a true Target of Opportunity and needs to be scheduled as soon as possible. ------------------------------------------------------------------------------------ 9576( 5) - 02/06/02 11:55 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V838MON STAR, NOVA-LIKE RA=07H 4M 4.79S +/- 0.3", DEC=- J2000 V = 7.0+/-0.5 03D 50' 50.2" +/- 0.3", PLATE- ID=00TT Coordinate Source: GUIDE_STAR_CATALOG Comments: The above coordinate is from http://pixela.stsci.edu/htbin/rcat_request.com. In GSC II it's object S10023301078. The Identification is based on our own astrometry using 20 GSC stars on a CCD frame, which gave RA: 07h04m04.823, DEC: - 03d50'50.64", RMS 0.15". The GSC object seems to be a blend of two stars. Two other independent coordinate measurements are available: a) RA 07h04m04.801, DEC: - 03d50'50.77" based on 29 Tycho-2 stars (IAU Circ. 7786), b) RA: 07h04m04.85s, DEC: -03d50'51.1" using 30 USNO-A2.0 stars (IAU Circ. 7785). The field around the target is rather crowded with faint stars on the DSS. Within 1.5 arcmin no object brighter 14th mag is visible so the standard ACQ procedure should have no difficulty in picking up the target. 9576( 5) - 02/06/02 11:55 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 V838MON STIS/C ACQ F25ND3 MIRROR 1 0.2 S CD Comments: V838 Mon has undergone brightening of more than 3 mags between Feb 2nd to 5th. It seems to be stabilizing now. The most reliable photometric data put the star at 7.0 +/- 0.5 for Feb 06th. As the spectral energy distribution of the object is not known, we prefer F25ND3 (0.2s) for a safe ACQ of the target. With the above set up changes in brightness of up the 1.5 mag brighter and more than 2 mag fainter can be accomodated. ------------------------------------------------------------------------------------------------------------------------------------ 20 V838MON STIS/C ACCUM 52X0.2 G230LB 2375 1 60 S CD ------------------------------------------------------------------------------------------------------------------------------------ 30 V838MON STIS/C ACCUM 52X0.2 G230LB 2375 1 662 S CD ------------------------------------------------------------------------------------------------------------------------------------ 40 V838MON STIS/C ACCUM 52X0.2 G230LB 2375 1 662 S CD ------------------------------------------------------------------------------------------------------------------------------------ 50 V838MON STIS/C ACCUM 52X0.2 G230LB 2375 1 662 S CD ------------------------------------------------------------------------------------------------------------------------------------ 9576( 5) - 02/06/02 11:55 - [ 5] Summary Form for Proposal 9576 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND3 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G230LB ------------------------------------------------------------------------------------------------------------------------------------ Target Names V838MON ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2375 ------------------------------------------------------------------------------------------------------------------------------------