6126( 0) - 07/18/95 20:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6126 Version: ********** Check-in Date: ********** 1.Proposal Title: Evolution of Binary Neutron Stars and Their White Dwarf Companions ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Hot Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Roger Foster Naval Research Laboratory CoI: Dr. Scott Lundgren Naval Research Laboratory Y CoI: Fernando Camilo Princeton University N ------------------------------------------------------------------------------------ 6. Abstract Understanding the age and evolutionary history of millisecond pulsars can be greatly enhanced by careful multi-color photometry of the white dwarf companions to binary millisecond pulsars. Twenty two millisecond pulsars have been identified with low- mass companions, the majority being 0.1 to 0.6 Msun white dwarfs. We have selected the six most promising pulsar-white dwarf systems for study with HST. Photometry in B, V, and I filters will be used to determine the cooling age of the dwarf star independent of evolutionary arguments made from timing measurements of the pulsar. In several cases the estimated companion mass, determined from the luminosity, will place significant upper bounds on the neutron star mass, potentially revealing clues about both the supernova explosion which created the neutron star, and the later accretion which spun it up to millisecond periods. Astrometric observations of the white dwarfs will serve as a first epoch of proper motion measurements important for distinguishing between supernova and accretion induced collapse models for millisecond pulsar formation. Finally, the astrometry will enable us to measure the rotation of the optical reference frame relative to the radio and dynamical reference frames made from independent pulsar observations. ------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 2] Observations Description ------------------------ We propose to image 2 pulsar companions in 3 colors and 4 companions in 2 colors each. In order to accurately fit for reddening and temperature, we require signal to noise ratios on the order of 20. From Palomar observations currently being reduced, PSR J1713+0747 and PSR J2145-0750 are barely detected at m_v~ 24.5-25. From their comparable ages and estimated white dwarf masses, the other pulsars are expected to have comparable luminosities. Hence, they could be up to 1 magnitude fainter due to larger distance, smaller size, or higher age. To reach the desired signal, we require 1 orbit for 2 colors or 2 orbits for 3 colors per object. Due to reddening, low white dwarf temperature, and lower telescope sensitivity, the B filter requires the longest integration. We propose two 7.5 minute exposures each for the V and I filters in the first orbit and two 20 minute exposures with the B filter in the second orbit. These exposures give 400-600 counts for a signal to noise ratio of 15-20 integrated over the point spread function (combined sky background (4), dark current (2), and read noise (25) counts amount to about 280 over the point spread function). The limiting magnitude would be 27 for each filter, significantly fainter than expected for any of the objects. For the objects in this project, the fraction of neutron star spin-down energy impinging on the companion is not sufficient to cause substantial heating. Hence, none of the recently discovered systems are expected to show orbital variability of the companion luminosity. The PSR 1957+20 system, which does show optical variability over the orbit (Fruchter et al 1988) has more spin-down energy and a smaller orbit than the recently discovered systems. Even if the energy was sufficient in the new systems, the chance is small that the spin and orbital axes are oriented favorably, such that the pulsar beam intercepts the companion. Consequently, we can safely make each observations for each filter at different orbital phase values. Real Time Justification ----------------------- None. Radio timing observations are ongoing and will continue for all of these objects. J0034-0534 and J2145-0750 are monitored by Bailes at Parkes observatory. J1023+1004, J2019+2425, and J2229+2643 are observed at Arecibo observatory by Camilo. Foster observes J1640+2224 and J1713+0747 at Arecibo and Wolszczan monitors them at Bonn. Typically each source is observed monthly to monitor fluctuations from the fitted timing and orbital model. With a long enough time baseline these observations will be used to fit for positions and proper motions, to compare with the optical results. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-2145- STAR, BINARY PULSAR RA=21H 45M 50.440S +/- 0.005S, J2000 V=25. +/- 1. 0750 DEC=-7D 50' 17.9" +/- 0.2" 2 STAR-0034- STAR, BINARY PULSAR RA=00H 34M 21.826S +/- 0.002S, J2000 V=25. +/- 1. 0534 DEC=-05D 34' 36.56" +/- 0.03" 3 STAR- STAR, BINARY PULSAR RA=10H 22M 58.095S +/- 0.15S, J2000 V=24.5 +/- 1. 1022+1001 DEC=+10D 01' 55.8" +/- 5" Comments: The new name reflects improvements in the position from radio timing of the pulsar. An improved position with accuracy better than 1 arcsecond will be provided by April 1995. 4 STAR- STAR, BINARY PULSAR RA=16H 40M 16.742S +/- 0.001S, J2000 V=26. +/- 1. 1640+2224 DEC=+22D 24' 09.015" +/- 0.003" 5 STAR- STAR, BINARY PULSAR RA=17H 13M 49.527S +/- 0.001S, J2000 V=25. +/- 1. 1713+0747 DEC=+07D 47' 37.556" +/- 0.001" 6 STAR- STAR, BINARY PULSAR RA=20H 19M 31.951S +/- 0.001S, J2000 V=25. +/- 1. 2019+2425 DEC=+24D 25' 15.366" +/- 0.01" 6126( 0) - 07/18/95 20:13 - [ 5] Visit: 01 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-2145- WFPC2 IMAGE PC1 F439W 1 2150S EXPAND 0750 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR-2145- WFPC2 IMAGE PC1 F814W 1 950S EXPAND 0750 ------------------------------------------------------------------------------------------------------------------------------------ 3 STAR-2145- WFPC2 IMAGE PC1 F555W 1 1200S EXPAND 0750 ------------------------------------------------------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 6] Visit: 02 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR- WFPC2 IMAGE PC1 F439W 1 2150S EXPAND 1713+0747 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR- WFPC2 IMAGE PC1 F814W 1 950S EXPAND 1713+0747 ------------------------------------------------------------------------------------------------------------------------------------ 3 STAR- WFPC2 IMAGE PC1 F555W 1 1200S EXPAND 1713+0747 ------------------------------------------------------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 7] Visit: 03 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR-0034- WFPC2 IMAGE PC1 F814W 1 900S EXPAND 0534 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR-0034- WFPC2 IMAGE PC1 F555W 1 1100S EXPAND 0534 ------------------------------------------------------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 8] Visit: 04 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR- WFPC2 IMAGE PC1 F814W 1 900S EXPAND 1022+1001 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR- WFPC2 IMAGE PC1 F555W 1 1100S EXPAND 1022+1001 ------------------------------------------------------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 9] Visit: 05 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR- WFPC2 IMAGE PC1 F814W 1 900S EXPAND 1640+2224 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR- WFPC2 IMAGE PC1 F555W 1 1100S EXPAND 1640+2224 ------------------------------------------------------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 10] Visit: 06 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 STAR- WFPC2 IMAGE PC1 F814W 1 900S EXPAND 2019+2425 ------------------------------------------------------------------------------------------------------------------------------------ 2 STAR- WFPC2 IMAGE PC1 F555W 1 1100S EXPAND 2019+2425 ------------------------------------------------------------------------------------------------------------------------------------ 6126( 0) - 07/18/95 20:13 - [ 11] Summary Form for Proposal 6126 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Hot Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements EXPAND ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F439W F814W F555W ------------------------------------------------------------------------------------------------------------------------------------ Target Names STAR-2145-0750 STAR-1713+0747 STAR-0034-0534 STAR-1022+1001 STAR-1640+2224 STAR-2019+2425 ------------------------------------------------------------------------------------------------------------------------------------