The Library

A census of AM CVn stars : three new candidates and one confirmed 48.3-minute binary

Tools

Rau, Arne, Roelofs, Gijs H. A., Groot, P. J., Marsh, T. R., Nelemans, G., Steeghs, D., Salvato, M. and Kasliwal, M. M.. (2010) A census of AM CVn stars : three new candidates and one confirmed 48.3-minute binary. Astrophysical Journal, Vol.708 (No.1). pp. 456-461. ISSN 0004-637X

Preview

Text
WRAP_Steeghs_AM_CVn_0909.4542v1.pdf - Accepted Version
Download (849Kb) | Preview

Official URL: http://dx.doi.org/10.1088/0004-637X/708/1/456

Abstract

We present three new candidate AM CVn binaries, and one confirmed new system, from a spectroscopic survey of color-selected objects from the Sloan Digital Sky Survey (SDSS). All four systems were found from their helium emission lines in low-resolution spectra taken on the Hale telescope at Palomar, the Nordic Optical Telescope, and the William Herschel Telescope on La Palma. The ultra-compact binary nature of SDSS J090221.35+381941.9 was confirmed using phase-resolved spectroscopy at the Keck-I telescope. From the characteristic radial velocity "S-wave" observed in the helium emission lines, we measure an orbital period of 48.31 +/- 0.08 minutes. The continuum emission can be described with a blackbody or a helium white dwarf atmosphere of T-eff similar to 15,000 K, in agreement with theoretical cooling models for relatively massive accretors and/or donors. The absence in the spectrum of broad helium absorption lines from the accreting white dwarf suggests that the accreting white dwarf cannot be much hotter than 15,000 K, or that an additional component such as the accretion disk contributes substantially to the optical flux. Two of the candidate systems, SDSS J152509.57+360054.5 and SDSS J172102.48+273301.2, do show helium absorption in the blue part of their spectra in addition to the characteristic helium emission lines. This in combination with the high effective temperatures of similar to 18,000 K and similar to 16,000 K suggests both to be at orbital periods below similar to 40 minutes. The third candidate, SDSS J164228.06+193410.0, exhibits remarkably strong helium emission on top of a relatively cool (T-eff similar to 12,000 K) continuum, indicating an orbital period above similar to 50 minutes.

Item Type:

Journal Article

Subjects:

Q Science > QB Astronomy

Divisions:

Faculty of Science > Physics

Library of Congress Subject Headings (LCSH):

Double stars, White dwarf stars

Journal or Publication Title:

Astrophysical Journal

Publisher:

IOP Publishing

ISSN:

0004-637X

Official Date:

1 January 2010

Dates:

Date	Event
1 January 2010	Published

Volume:

Vol.708

Number:

No.1

Number of Pages:

Page Range:

pp. 456-461

DOI:

10.1088/0004-637X/708/1/456

Status:

Peer Reviewed

Publication Status:

Published

Access rights to Published version:

Restricted or Subscription Access

Funder:

United States. National Aeronautics and Space Administration (NASA), Nederlandse Organisatie voor Wetenschappelijk Onderzoek [Netherlands Organisation for Scientific Research] (NWO), Science and Technology Facilities Council (Great Britain) (STFC), W. M. Keck Foundation

Grant number:

680.50.0610 (NWO), NNX08AK66G (NASA)

Related URLs:

Other Repository

References:

Anderson S.F., Haggard, D., Homer, L., et al., 2005, AJ 130, 2230
Bildsten, L., Shen, K. J., Weinberg, N. N., & Nelemans, G. 2007,
ApJ, 662, L95
Bildsten, L., Townsley, D. M., Deloye, C. J., & Nelemans, G. 2006,
ApJ, 640, 466
Cropper, M., Harrop-Allin, M. K., Mason, K. O., Mittaz, J. P. D.,
Potter, S. B., & Ramsay, G. 1998, MNRAS, 293, L57
Deloye, C. J., Bildsten, L., & Nelemans, G. 2005, ApJ, 624, 934
Deloye, C. J., Taam, R. E., Winisdoerffer, C., & Chabrier, G. 2007,
MNRAS, 381, 525
Groot, P. J., Nelemans, G., Steeghs, D., & Marsh, T. R. 2001, ApJ,
558, L123
Israel, G. L., Hummel, W., Covino, S., Campana, S., Appenzeller,
I., Gassler, W., Mantel, K.-H., Marconi, G., Mauche, C. W.,
Munari, U., Negueruela, I., Nicklas, H., Rupprecht, G., Smart,
R. L., Stahl, O., & Stella, L. 2002, A&A, 386, L13
Koester, D. 2008, in Mem.S.A.I., lectures at the School of
Astrophysics "F. Lucchin", Tarquinia, astro-ph/0812.0482
Marsh, T. R. 1999, MNRAS, 304, 443
Marsh, T. R. & Horne, K. 1988, MNRAS, 235, 269
Marsh, T. R., Horne, K., & Rosen, S. 1991, ApJ, 366, 535
Morales-Rueda, L., Marsh, T. R., Steeghs, D., Unda-Sanzana, E.,
Wood, J. H., & North, R. C. 2003, A&A, 405, 249
Nather, R. E., Robinson, E. L., & Stover, R. J. 1981, ApJ, 244,
269
Nelemans, G. 2005, in Astronomical Society of the Pacific
Conference Series, Vol. 330, The Astrophysics of Cataclysmic
Variables and Related Objects, ed. J.-M. Hameury & J.-P.
Lasota, 27
Nelemans, G., Portegies Zwart, S. F., Verbunt, F., & Yungelson,
L. R. 2001, A&A, 368, 939
Nelemans, G., Yungelson, L. R., & Portegies Zwart, S. F. 2004,
MNRAS, 349, 181
Oke, J. B. 1990, AJ, 99, 1621
Oke, J. B., Cohen, J. G., Carr, M., Cromer, J., Dingizian, A.,
Harris, F. H., Labrecque, S., Lucinio, R., Schaal, W., Epps, H.,
& Miller, J. 1995, PASP, 107, 375
Oke, J. B. & Gunn, J. E. 1982, PASP, 94, 586
Podsiadlowski, P., Han, Z., & Rappaport, S. 2003, MNRAS, 340,
1214
Roelofs, G. H. A., Groot, P. J., Marsh, T. R., Steeghs, D., Barros,
S. C. C., & Nelemans, G. 2005, MNRAS, 361, 487
Roelofs, G. H. A., Groot, P. J., Marsh, T. R., Steeghs, D., &
Nelemans, G. 2006a, MNRAS, 365, 1109
Roelofs, G. H. A., Groot, P. J., Nelemans, G., Marsh, T. R., &
Steeghs, D. 2006b, MNRAS, 371, 1231
Roelofs, G. H. A., Groot, P. J., Benedict, G. F., McArthur, B. E.,
Steeghs, D., Morales-Rueda, L., Marsh, T. R., & Nelemans, G.
2007a, ApJ, 666, 1174
Roelofs, G. H. A., Groot, P. J., Steeghs, D., Marsh, T. R., &
Nelemans, G. 2007b, MNRAS, 382, 1643
Roelofs, G. H. A., Nelemans, G. & Groot, P. J., 2007c, MNRAS,
382, 685
Roelofs, G. H. A., Groot, P. J., Nelemans, G., Marsh, T. R., &
Steeghs, D. 2007d, MNRAS, 379, 176
Roelofs, G. H. A. 2007, PhD Thesis, Radboud University Nijmegen,
The Netherlands, ISBN 978-90-9021724-6
Roelofs, G. H. A., Groot, P. J., Steeghs, D., Rau, A., de Groot,
E., Marsh, T. R., Nelemans, G., Liebert, J., & Woudt, P. 2009,
MNRAS, 394, 367
Ruiz, M. T., Rojo, P. M., Garay, G., & Maza, J. 2001, ApJ, 552,
679
Schlegel, D. J., Finkbeiner, D. P., Davis, M. 1998, ApJ, 500, 525
Stroeer, A., Vecchio, A., & Nelemans, G. 2005, ApJ, 633, L33
York, D. G. et al. 2000, AJ, 120, 1579