A Caltech Library Service

Physical properties of AM CVn stars: New insights from Gaia DR2

Ramsay, G. and Green, M. J. and Marsh, T. R. and Kupfer, T. and Breedt, E. and Korol, V. and Groot, P. J. and Knigge, C. and Nelemans, G. and Steeghs, D. and Woudt, P. and Aungwerojwit, A. (2018) Physical properties of AM CVn stars: New insights from Gaia DR2. Astronomy and Astrophysics, 620 . Art. No. A141. ISSN 0004-6361.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


AM CVn binaries are hydrogen deficient compact binaries with an orbital period in the 5–65 min range and are predicted to be strong sources of persistent gravitational wave radiation. Using Gaia Data Release 2, we present the parallaxes and proper motions of 41 out of the 56 known systems. Compared to the parallax determined using the HST Fine Guidance Sensor we find that the archetype star, AM CVn, is significantly closer than previously thought. This resolves the high luminosity and mass accretion rate which models had difficulty in explaining. Using Pan-STARRS1 data we determine the absolute magnitude of the AM CVn stars. There is some evidence that donor stars have a higher mass and radius than expected for white dwarfs or that the donors are not white dwarfs. Using the distances to the known AM CVn stars we find strong evidence that a large population of AM CVn stars has yet to be discovered. As this value sets the background to the gravitational wave signal of LISA this is of wide interest. We determine the mass transfer rate for 15 AM CVn stars and find that the majority has a rate significantly greater than expected from standard models. This is further evidence that the donor star has a greater size than expected.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Ramsay, G.0000-0001-8722-9710
Green, M. J.0000-0002-0948-4801
Marsh, T. R.0000-0002-2498-7589
Kupfer, T.0000-0002-6540-1484
Breedt, E.0000-0001-6180-3438
Groot, P. J.0000-0002-4488-726X
Woudt, P.0000-0002-6896-1655
Additional Information:© ESO 2018. Received 17 September 2018 / Accepted 14 October 2018. This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. We extracted GALEX data from Multi-Mission archive at the Space Telescope Science Institute (MAST). The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Centre for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. The national facility capability for SkyMapper has been funded through ARC LIEF grant LE130100104 from the Australian Research Council, awarded to the University of Sydney, the Australian National University, Swinburne University of Technology, the University of Queensland, the University of Western Australia, the University of Melbourne, Curtin University of Technology, Monash University and the Australian Astronomical Observatory. SkyMapper is owned and operated by The Australian National University’s Research School of Astronomy and Astrophysics. The survey data were processed and provided by the SkyMapper Team at ANU. The SkyMapper node of the All-Sky Virtual Observatory (ASVO) is hosted at the National Computational Infrastructure (NCI). Development and support the SkyMapper node of the ASVO has been funded in part by Astronomy Australia Limited (AAL) and the Australian Government through the Commonwealth’s Education Investment Fund (EIF) and National Collaborative Research Infrastructure Strategy (NCRIS), particularly the National eResearch Collaboration Tools and Resources (NeCTAR) and the Australian National Data Service Projects (ANDS). This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration 2018). Armagh Observatory and Planetarium is core funded by the Northern Ireland Executive through the Dept for Communities. MJG acknowledges funding from an STFC studentship via grant number ST/N504506/1. A.A. acknowledges the support of the National Research Council of Thailand (grant number R2561B087).
Funding AgencyGrant Number
Gaia Multilateral AgreementUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Australian Research CouncilLE130100104
Science and Technology Facilities Council (STFC)ST/N504506/1
National Research Council of ThailandR2561B087
Subject Keywords:accretion, accretion disks / stars: distances / white dwarfs
Record Number:CaltechAUTHORS:20190102-155140098
Persistent URL:
Official Citation:Physical properties of AM CVn stars: New insights from Gaia DR2 G. Ramsay, M. J. Green, T. R. Marsh, T. Kupfer, E. Breedt, V. Korol, P. J. Groot, C. Knigge, G. Nelemans, D. Steeghs, P. Woudt and A. Aungwerojwit A&A, 620 (2018) A141 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92020
Deposited By: George Porter
Deposited On:03 Jan 2019 19:33
Last Modified:09 Mar 2020 13:18

Repository Staff Only: item control page