Geminga: A cooling superfluid neutron star
Geminga: A cooling superfluid neutron star
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Geminga：冷却超流体中子星
DOI：
10.1086/174236
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
D. Page
中科院分区：
文献类型：
--
作者：
D. Page
我们比较了最近对Geminga的温度估计和中子星冷却模型。由于它的年龄(大约3.4x10(Exp 5)年)，Geminga处于光子冷却时代。结果表明，它的表面温度(约5.2×10(Exp 5)K)可以用两种中微子冷却方案来理解，即通过修正的URCA过程的慢中微子冷却或通过直接URCA过程或某些奇异物质的快速中微子冷却，因此不允许我们区分这两种相互竞争的方案。然而，对于这两种情况，只有在恒星核心的大部分(如果不是全部)存在重子配对的情况下，才能与观测到的温度一致。在中微子缓慢冷却的情况下，早期的中微子冷却不足以解释观察到的低温，在目前的光子冷却时代，核心中广泛的配对是必要的，以减少比热和提高冷却速度。在所有快速中微子冷却的情况下，整个核心都需要配对来控制巨大的早期中微子发射，如果没有配对抑制，目前的表面温度将比观测到的低得多。我们还评论了最近对PSR0656+14和PSR1055-52的温度估计，它们属于同一光子冷却时代。如果假设所有中子星都经历了快速的中微子冷却，那么这两个天体也提供了它们核心中广泛存在重子配对的证据；但观测的不确定性也允许更保守的解释，即中微子发射缓慢，根本没有配对。然而，我们认为，慢中微子冷却模型(标准模型)的观测证据实际上非常模糊，只有在快速中微子冷却的情况下，才能用合理的理论先验来解释所有中子星的表面温度。在这种情况下，Geminga、PSR0656+14和PSR1055-52都显示出重子配对到它们的中心的证据。
We compare the recent temperature estimate for Geminga with neutron star cooling models. Because of its age (approximately 3.4 x 10(exp 5) yr), Geminga is in the photon cooling era. We show that its surface temperature (approximately 5.2 x 10(exp 5) K) can be understood by both types of neutrino cooling scenarios, i.e., slow neutrino cooling by the modified Urca process or fast neutrino cooling by the direct Urca process or by some exotic matter, and thus does not allow us to discriminate between these two competing schemes. However, for both types of scenarios, agreement with the observed temperature can only be obtained if baryon pairing is present in most, if not all, of the core of the star. Within the slow neutrino cooling scenario, early neutrino cooling is not sufficient to explain the observed low temperature, and extensive pairing in the core is necessary to reduce the specific heat and increase the cooling rate in the present photon cooling era. Within all the fast neutrino cooling scenarios, pairing is necessary throughout the whole core to control the enormous early neutrino emission which, without pairing suppression, would result in a surface temperature at the present time much lower than observed. We also comment on the recent temperature estimates for PSR 0656+14 and PSR 1055-52, which pertain to the same photon cooling era. If one assumes that all neutron stars undergo fast neutrino cooling, then these two objects also provide evidence for extensive baryon pairing in their core; but observational uncertainties also permit a more conservative interpretation, with slow neutrino emission and no pairing at all. We argue though that observational evidence for the slow neutrino cooling model (the 'standard' model) is in fact very dim and that the interpretation of the surface temperature of all neutron stars could be done with a reasonable theoretical a priori within the fast neutrino cooling scenarios only. In this case, Geminga, PSR 0656+14, and PSR 1055-52 all show evidence of baryon pairing down to their very centers.