Precise mass and radius values for the white dwarf and low mass M dwarf in the pre-cataclysmic binary NN Serpentis

Details Precise mass and radius values for the white dwarf and low mass M dwarf in the pre-cataclysmic binary NN Serpentis Precise mass and radius values for the white dwarf and low mass M dwarf in the pre-cataclysmic binary NN Serpentis

2009-09-23

arxiv.org/abs/0909.4307v2

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

20 pages, 17 figures, 8 tables, minor changes, accepted for publication in MNRAS

Scientific paper

10.1111/j.1365-2966.2009.16072.x

We derive precise system parameters for the pre-cataclysmic binary, NN Ser. From light curve fitting we find an orbital inclination of i = 89.6 +/- 0.2 deg. From the HeII absorption line we find K_{WD}= 62.3 +/- 1.9 km/s. The irradiation-induced emission lines from the surface of the secondary star give a range of observed radial velocities. The corrected values give a radial velocity of K_{sec}= 301 +/- 3 km/s, with an error dominated by the systematic effects of the model. This leads to a binary separation of a = 0.934 +/- 0.009 R_{sun}, radii of R_{WD} = 0.0211 +/- 0.0002 R_{sun} and R_{sec} = 0.149 +/- 0.002 R_{sun} and masses of M_{WD} = 0.535 +/- 0.012 M_{sun} and M_{sec} = 0.111 +/- 0.004 M_{sun}. The masses and radii of both components of NN Ser were measured independently of any mass-radius relation. For the white dwarf, the measured mass, radius and temperature show excellent agreement with a `thick' hydrogen layer of fractional mass M_{H}/{M}_{WD} = 10^{-4}. The measured radius of the secondary star is 10% larger than predicted by models, however, correcting for irradiation accounts for most of this inconsistency, hence the secondary star in NN Ser is one of the first precisely measured very low mass objects to show good agreement with models. ULTRACAM r', i' and z' photometry taken during the primary eclipse determines the colours of the secondary star as (r'-i')_{sec}= 1.4 +/- 0.1 and (i'-z')_{sec} = 0.8 +/- 0.1 which corresponds to a spectral type of M4 +/- 0.5. This is consistent with the derived mass, demonstrating that there is no detectable heating of the unirradiated face, despite intercepting radiative energy from the white dwarf which exceeds its own luminosity by over a factor of 20.

Affiliated with

Also associated with

No associations

Rating

Precise mass and radius values for the white dwarf and low mass M dwarf in the pre-cataclysmic binary NN Serpentis does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Precise mass and radius values for the white dwarf and low mass M dwarf in the pre-cataclysmic binary NN Serpentis, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Precise mass and radius values for the white dwarf and low mass M dwarf in the pre-cataclysmic binary NN Serpentis will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-424477