---
res:
  bibo_abstract:
  - Ultracompact binary systems, consisting of two compact objects in an orbit $\lesssim
    0.5 {\rm R}_\odot$, should exhibit measurable rates of orbital period change ($\dot{P}
    \ne 0$) due to the emission of gravitational waves (GWs). Measurements of $\dot{P}$
    have so far been limited to the shortest-period ultracompact binaries ($\lesssim
    20$  min). Among the AM CVn-type subclass, several works have proposed the presence
    of extra angular momentum loss beyond GW emission, with magnetic braking being
    a widely discussed mechanism. If present, this magnetic braking would dominate
    the angular momentum loss of AM CVn-type binaries with orbital periods $\gtrsim
    30$ min. In this work, we present a long-term eclipse timing study of two AM CVn-type
    binaries, YZ LMi and Gaia14aae, with respective orbital periods of 28.3 min and
    49.7 min and continuous observations since 2006 and 2015. Both systems show $\dot{P}$
    consistent with zero within $2\sigma$. Their $3\sigma$ upper limits are $1.1 \times
    10^{-13}\, {\rm s \, s}^{-1}$ and $9.7 \times 10^{-14}\, {\rm s \, s}^{-1}$, respectively.
    These non-detections are most simply explained by a scenario in which secular
    angular momentum loss is not substantially stronger than GW emission at all orbital
    periods, but is combined with deviations from the secular $\dot{P}$ whose time-scales
    span decades but whose amplitude is $\lesssim 10^{-13}\, {\rm s \, s}^{-1}$. Our
    non-detections of $\dot{P}$ represent a limit on the strength of any enhanced
    angular momentum loss beyond pure GW emission.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Matthew J
      foaf_name: Green, Matthew J
      foaf_surname: Green
  - foaf_Person:
      foaf_givenName: Thomas R
      foaf_name: Marsh, Thomas R
      foaf_surname: Marsh
  - foaf_Person:
      foaf_givenName: Joannes C
      foaf_name: van Roestel, Joannes C
      foaf_surname: van Roestel
      foaf_workInfoHomepage: http://www.librecat.org/personId=4d122fc8-6083-11f0-87a5-97d68b860333
  - foaf_Person:
      foaf_givenName: Tin Long Sunny
      foaf_name: Wong, Tin Long Sunny
      foaf_surname: Wong
  - foaf_Person:
      foaf_givenName: Diogo
      foaf_name: Belloni, Diogo
      foaf_surname: Belloni
  - foaf_Person:
      foaf_givenName: Mukremin
      foaf_name: Kilic, Mukremin
      foaf_surname: Kilic
  - foaf_Person:
      foaf_givenName: Elmé
      foaf_name: Breedt, Elmé
      foaf_surname: Breedt
  - foaf_Person:
      foaf_givenName: Alex
      foaf_name: Brown, Alex
      foaf_surname: Brown
  - foaf_Person:
      foaf_givenName: Chris M
      foaf_name: Copperwheat, Chris M
      foaf_surname: Copperwheat
  - foaf_Person:
      foaf_givenName: Anurak
      foaf_name: Chakpor, Anurak
      foaf_surname: Chakpor
  - foaf_Person:
      foaf_givenName: V S
      foaf_name: Dhillon, V S
      foaf_surname: Dhillon
  - foaf_Person:
      foaf_givenName: Noel Castro
      foaf_name: Segura, Noel Castro
      foaf_surname: Segura
  - foaf_Person:
      foaf_givenName: Martin J
      foaf_name: Dyer, Martin J
      foaf_surname: Dyer
  - foaf_Person:
      foaf_givenName: James
      foaf_name: Garbutt, James
      foaf_surname: Garbutt
  - foaf_Person:
      foaf_givenName: Dan
      foaf_name: Jarvis, Dan
      foaf_surname: Jarvis
  - foaf_Person:
      foaf_givenName: Vasu
      foaf_name: Kengkriangkrai, Vasu
      foaf_surname: Kengkriangkrai
  - foaf_Person:
      foaf_givenName: Mark R
      foaf_name: Kennedy, Mark R
      foaf_surname: Kennedy
  - foaf_Person:
      foaf_givenName: Paul
      foaf_name: Kerry, Paul
      foaf_surname: Kerry
  - foaf_Person:
      foaf_givenName: Thomas
      foaf_name: Kupfer, Thomas
      foaf_surname: Kupfer
  - foaf_Person:
      foaf_givenName: S P
      foaf_name: Littlefair, S P
      foaf_surname: Littlefair
  - foaf_Person:
      foaf_givenName: James
      foaf_name: McCormac, James
      foaf_surname: McCormac
  - foaf_Person:
      foaf_givenName: James
      foaf_name: Munday, James
      foaf_surname: Munday
  - foaf_Person:
      foaf_givenName: Steven G
      foaf_name: Parsons, Steven G
      foaf_surname: Parsons
  - foaf_Person:
      foaf_givenName: Eleanor
      foaf_name: Pike, Eleanor
      foaf_surname: Pike
  - foaf_Person:
      foaf_givenName: Ingrid
      foaf_name: Pelisoli, Ingrid
      foaf_surname: Pelisoli
  - foaf_Person:
      foaf_givenName: Pablo
      foaf_name: Rodríguez-Gil, Pablo
      foaf_surname: Rodríguez-Gil
  - foaf_Person:
      foaf_givenName: David I
      foaf_name: Sahman, David I
      foaf_surname: Sahman
  - foaf_Person:
      foaf_givenName: Amalie
      foaf_name: Yates, Amalie
      foaf_surname: Yates
  bibo_doi: 10.1093/mnras/stag673
  bibo_issue: '3'
  bibo_volume: 548
  dct_date: 2026^xs_gYear
  dct_isPartOf:
  - http://id.crossref.org/issn/0035-8711
  - http://id.crossref.org/issn/1365-2966
  dct_language: eng
  dct_publisher: Oxford University Press@
  dct_subject:
  - 'binaries: close – stars'
  - dwarf novae – novae
  - cataclysmic variables – white dwarfs
  dct_title: No period change in two long-period AM CVn binaries@
...