Millisecond Pulsar Catalogue

List of rotation and accretion powered millisecond pulsars

compiled by Alessandro Patruno
last updated 5 Aug 2014

If you spot a mistake please submit a correction with this form:

NOTES

The pulsars are shown with their spin period in ascending order. The AMXPs are instead displayed at the end of the table.

The criteria used for sources selections are the following:

  • Spin period < 30 ms
  • Surface Magnetic Field < 1e11 G

[The source B1718-19 (spin P~1 s) is not included even if this is a Redback]

An ASCII version of the table is available upon request

Resources: ATNF pulsar catalogue
P. Freire’s globular cluster catalogue
D. Lorimer’s Catalogue
A. Patruno & A. Watts 2012 “Accreting Millisecond X-Ray Pulsars”
M. Roberts 2012 “Surrounded by Spiders”

Source Type Notation:

MSP = millisecond pulsar in the field
MSP-GC = millisecond pulsar in globular cluster
RB-F = Redback in the field
RB-GC = Redback in globular cluster
BW-F = Black Widow in the field
BW-GC = Black Widow in globular cluster
AMXP = Accreting Millisecond X-Ray Pulsar
MSP-DNS= millisecond pulsar with neutron star companion
MSP-planet = millisecond pulsar with planetary size companion
MSP-triple = millisecond pulsar in a triple system (MSP + 2 WDs)

Legend:

P = spin period (in seconds); PDOT = spin period derivative; DM = dispersion measure; DIST = distance [kiloparsecs]; A1 = projected orbital semimajor axis [in light-seconds]; PB = orbital period [days]; ECC = eccentricity; MIN MASS = minimum companion mass in Solar mass units; TYPE = pulsar type;

 

NAME P
[s]
PDOT DM DIST
[kpc]
A1
[lt-s]
PB
[d]
Ecc Min
Mass [Msun]
TYPE
J1748-2446ad 0.00139595 0 235.6 * 1.1028 1.09443 0 0.16 RB-GC
B1937+21 0.001557806472 1.051212E-19 71.0398 5.00 * * * * MSP
B1957+20 0.001607401684 1.68515E-20 29.1168 1.53 0.0892253 0.3819666069 0.00000 0.021423 BW-F
J1747-4036 0.00165 * 152.9 5.74 * * * * MSP
J1810+17 0.00166 * 39.7 2.49 * 0.15 * 0.044 BW-F
J1748-2446O 0.00167663 0 236.38 * 0.112 0.2595 0 0.04 BW-GC
J1023+0038 0.0016879874440059 1.2E-20 14.325 1.37 0.3433494 0.1980962019 * 0.134647 RB-F
J1227-4853 0.001690 * 48.5 * NA 0.288 * * RB-F
J1748-2446P 0.00172862 0 238.79 * 1.272 0.3626 0 0.44 RB-GC
J1902-5110 0.00174 * 36.3 2.11 * * * * MSP
J1301+0833 0.00184 * 13.2 0.91 * 0.27 * 0.024 BW-F
J1843-1113 0.001845666292 9.59E-21 59.96 1.97 * * * * MSP
J1723-2837 0.001855732795729 7.5E-21 19.688 1.00 1.225807 0.615436473 * 0.235930 RB-F
J0034-0534 0.001877181884 4.966E-21 13.76517 0.98 1.437769 1.589281801 1.4E-5 0.141098 MSP
J0955-61 0.00199 * 160.7 * * * * * MSP
J2052+12 0.00199 * 42.0 * * * * * MSP
J1431-4715 0.0020 * 59.4 * * * * * MSP
J1649+80 0.002010 * 31.0 * * * * * MSP
J1748-2446Y 0.00204816 0 239.11 * 1.16 1.17 0 0.16 MSP-GC
J1543-5149 0.002056960392 1.61E-20 50.92 1.46 6.480281 8.06077304 2.12E-5 0.223275 MSP
J1748-2446V 0.00207251 0 239.11 * 0.567 0.5036 0 0.14 MSP-GC
J0023-7203J 0.00210063 -9.7922e-21 24.5848 * 0.04040 0.12066 <0.00004 0.024 BW-GC
J1513-25 0.002120 * 46.9 * 0.053 0.197 * * MSP
J1805+06 0.00213 * 64.9 * * * * * MSP
J1903+0327 0.002149912364 1.88208E-20 297.5245 6.45 105.5934643 95.174118753 0.436678409 0.887294 MSP
J1544+4937 0.00215928839043292 2.933E-21 23.2258 2.30 0.0328680 0.1207729895 * 0.016967 BW-F
J1342+2822C 0.002166 0 26.5 * * * * * MSP-GC
J2241-5236 0.0021866997715528 6.64E-21 11.41085 0.68 0.02579537 0.1456722395 0E-5 0.011721 BW-F
J1446-4701 0.00219469577985001 9.8102E-21 55.83202 2.03 0.0640118 0.27766607732 2.11E-5 0.018988 BW-F
J0024-7204Y 0.00219666 0 24.2 * 0.67176 0.52194 0.0 0.16 MSP-GC
J1748-2446E 0.0021978 0 236.84 * 23.6 60.06 0.02 0.25 MSP-GC
J1748-2446L 0.0022447 0 237.74 * * * * * MSP-GC
J2256-1023 0.00229 * 13.8 0.91 * 0.21 * 0.034 BW-F
J1701-3006F 0.0022947270806719 2.221E-19 113.291 6.90 0.0573400 0.2054870422 0.0E-4 0.020807 BW-GC
J2017-16 0.002310 * 25.4 * * * * * MSP
J0218+4232 0.002320 * 61.2 * 1.984 2.029 * * MSP
J1017-7156 0.00233851444011854 2.2194E-21 94.22407 0.26 4.83004509 6.511905 0.00014204 0.189065 MSP
J1731-1847 0.002344559583 2.49E-20 106.56 4.04 0.1201594 0.311134124 10.0E-5 0.033268 BW-F
J0024-7204W 0.00235234 0 24.3 * 0.2435 0.1330 0.0 0.14 RB-GC
J0155+18 0.00236 * 19.8 * * * * * MSP
J2043+1711 0.002379878960 5.24E-21 20.70987 1.13 1.6239614 1.482290809 3.34E-6 0.169028 MSP
J1858-2216 0.00238 * 26.6 1.35 * 46.1 * * MSP
J1342+2822B 0.002389420757786 1.858E-20 26.148 10.40 1.875655 1.417352298 * 0.204240 MSP-GC
J1124-36 0.00241 * 44.9 4.40 * 0.225 * 0.027 BW-F
J2205+60 0.00241 * 103.7 * * * * * MSP
J1658-5317 0.00244 * 30.9 1.24 * * * * MSP
J1824-2452F 0.002451 0 123.8 * * * * * MSP-GC
J1748-2446Z 0.00246259 0 238.85 * 3.5304 3.48807 0.7608 0.25 MSP-GC
J1518+0204C 0.002484 0 29.3 * 0.057 0.087 0.0 0.04 BW-GC
J1641+3627E 0.002487 0 30.3 * 0.17 0.213 0.0 0.0195 BW-GC
J1921+01 0.002500 * 104.9 * 0 0 * * MSP
J1135+75 0.00251 * 29.2 * * * * * MSP
J0251+26 0.00254 * 20.2 * * * * * MSP
J1342+2822A 0.002545 0 26.5 * * * * * MSP-GC
J0557+15 0.00256 * 102.7 * 4.035 4.847 * * MSP
J1909+21 0.00256 * 61.9 * * * * * MSP
J1311-3430 0.002560371031 2.0964E-20 37.84 3.72 0.010581 0.0651157335 * 0.008210 BW-F
J0101-6422 0.0025731519721683 5.16E-21 11.926 0.73 1.701046 1.787596706 0E-6 0.155329 MSP
J0248+42 0.00260 * 48.2 * * * * * MSP
J1546-3747A 0.002605672246 * 92.17 7.66 1.38325 1.3467116 * 0.152356 MSP
J2114+54 0.002610 * 77.4 * 0.044 0.135 * * MSP
J2215+51 0.00261 * 69.2 3.30 * 0.18 * 0.22 RB-F
J2310-05 0.00261 * 15.5 * * * * * MSP
J0024-7204F 0.00262358 6.45e-20 24.379 * * * * * MSP-GC
J1938+20 0.002630 * 237.1 * 8.31 16.256 * * MSP
J1125-6014 0.002630380739 4.01E-21 52.951 1.94 8.339198 8.75260353 7.9E-7 0.278278 MSP
J0024-7204O 0.0026433432972417 3.0353E-20 24.363 4.00 0.045151 0.1359743050 * 0.021584 BW-GC
J1745+1017 0.0026521296710897 2.729E-21 23.970 1.36 0.088172 0.730241444 * 0.013692 BW-F
J1811-2405 0.00266059331683918 1.33774E-20 60.6005 1.70 5.7056616 6.2723020692 1.64E-6 0.233365 MSP
J1327-0755 0.0026779231971205 1.773E-20 27.91215 2.17 6.645774 8.439086019 8.5E-7 0.221958 MSP
J1832-0836 0.0027191120623197 8.62E-21 28.18 1.40 * * * * MSP
J0621+25 0.00272 * 83.6 4.25 * * * * MSP
J0605+37 0.00273 * 21.0 1.16 * 55.6 * * MSP
J0337+1715 0.00273258863244 1.7666E-20 21.3162 1.30 1.21752844 1.629401788 0.00069178 0.116203 MSP-triple
J1906+01 0.002790 * 126.9 0.625 0.609 * * * MSP
J1748-2446Q 0.002812 0 234.50 * 28.602 30.295 0.722 0.53 MSP-GC
J0024-7204S 0.00283041 -1.2054e-19 24.353 * 0.76627 1.20172 0.00039 0.10 MSP-GC
J0636+5128 0.00286 * 11.1 0.009 0.067 * * * MSP
J0742+6620 0.00288 * 15.0 3.978 4.7672012 * * * MSP
J2339-0533 0.00288 * 8.72 * 0.612 0.193 * 0.26 RB-F
J2017+0603 0.002896215815562 8.3E-21 23.918 1.32 2.1929239 2.198481129 2.3E-6 0.176041 MSP
J1909-3744 0.002947108068 1.402542E-20 10.3934 1.26 1.89799106 1.533449474590 1.301E-7 0.195357 MSP
J0102+4839 0.002960 * 53.5 4.03 1.856 1.672 * * MSP
J1748-2446K 0.00296965 0 234.81 * * * * * MSP-GC
J2229+2643 0.0029778192947556 1.46E-21 23.019 1.43 18.912513 93.0158934 0.0002556 0.122075 MSP
J1518+0204D 0.002988 0 29.3 * 1.6 1.22 0.0 0.2 MSP-GC
J1748-2446X 0.00299926 0 240.03 * 5.1071 4.99850 0.3024 0.29 MSP-GC
J1823-3021D 0.00302 0 86.9 * * * * * MSP-GC
J0023+09 0.00305 * 14.3 0.95 * 0.14 * 0.016 BW-F
J0024-7204N 0.00305395 -2.187e-20 24.57 * * * * * MSP-GC
B1821-24A 0.00305431 1.55e-18 120 * * * * * MSP-GC
J1807-2459A 0.00305945 0 134.0 * 0.01220 0.07109 0.0 0.010 BW-GC
J0613-0200 0.003061844086 9.5913E-21 38.77919 0.90 1.0914444 1.1985125753 0.55E-5 0.128556 MSP
J1536-4948 0.00308 * 38.0 1.34 * * * * MSP
J1400-14 0.003084232817 0.0E-19 4.934 0.27 8.419236 9.5476162 * 0.263524 MSP
J1012-42 0.00310 71.6 * * * * * * MSP
J1125-5825 0.00310221391893416 6.08990E-20 124.7946 2.98 33.6383599 76.40321683 0.00025724 0.263128 MSP
J1641+3627D 0.003118 0 30.6 * 0.92 0.591 0.0 0.18 MSP-GC
J2214+3000 0.003119226579 1.40E-20 22.557 1.32 0.0590800 0.416632943 0E-4 0.013334 BW-F
J0740+41 0.00314 * 21.0 * * * * * MSP
J0614-3329 0.003148669579439 1.75E-20 37.049 2.96 27.638787 53.5846127 0.0001801 0.275254 MSP
J1614-2230 0.0031508076534271 9.6216E-21 34.4865 1.77 11.2911975 8.6866194196 1.29E-6 0.396862 MSP
J0307+7443 0.00316 * 6.35 0.34 16.108 37.108 * * MSP
J1640+2224 0.00316331581791380 0.28276E-20 18.4260 1.19 55.3297198 175.46066194 0.000797262 0.246983 MSP
J1946+3417 0.003170139227806 0.0000037E-15 110 6.41 * 27 0.14 * MSP
J1518+0204E 0.003182 0 29.3 * 1.2 1.10 0.0 0.18 MSP-GC
J1816+4510 0.00319 * 38.9 * * 0.36 * 0.16 RB-F
J1905+0154A 0.003193 0 193.692 * 0.5886 0.81255 0.0 0.090 MSP-GC
J1628-3205 0.00321 * 42.1 1.54 * 0.21 * 0.16 RB-F
J0024-7204H 0.00321034 -1.83e-21 24.36 * 2.15281 2.35770 0.07056 0.19 MSP-GC
J1710+4923 0.00322 * 7.1 * 75.4 36.5 NA NA MSP
J1836-2354B 0.00323227 0 93.7 * * * * * MSP-GC
J1701-3006E 0.00323374 0 113.78 * 0.0701 0.15848 0.0 0.035 BW-GC
J1911-5958A 0.00326619 3.07e-21 33.68 * 1.20605 0.83711 <0.00001 0.22 MSP-GC
J1748-2446U 0.00328914 0 235.46 * 5.97248 3.57026 0.60498 0.45 MSP-GC
J0340+41 0.00329 * 49.6 2.67 * * * * MSP
J1748-2446af 0.00330434 0 237.34 * * * * * MSP-GC
J1630+37 0.00332 * 14.1 0.85 * 12.5 * * MSP
J1836-2354A 0.00335434 0 89.1 * 0.0464 0.20276 0.0 0.020 BW-GC
J1103-5403 0.003392709659 3.7E-21 103.915 3.16 * * * * MSP
J1036-83 0.00341 27.1 * * * * * * MSP
J1701-3006D 0.0034177704450548 1.257E-19 14.224 6.90 0.9880185 1.1179034034 0.0004122 0.121516 MSP-GC
J2317+1439 0.003445251071 2.42E-21 21.907 1.89 2.3139483 2.459331464 0.0000005 0.172079 MSP
J2317+1439 0.0034452510710225 2.42E-21 21.907 1.89 2.3139483 2.459331464 0.0000005 0.172079 MSP
J0751+1807 0.003478770783 7.7860E-21 30.2489 0.40 0.3966127 0.263144266723 7.1E-7 0.128346 MSP
J0024-7204R 0.00348046 0 24.4 * 0.0334 0.0662 0.0 0.030 BW-GC
J0024-7204I 0.00348499 -4.587e-20 24.42 * 0.03844 0.22979 <0.0004 0.015 BW-GC
J1721-2457 0.003496633782 5.542E-21 47.758 1.56 * * * * MSP
B1639+36B 0.00352807 0 29.5 * 1.389 1.25911 <0.001 0.19 MSP-GC
J0024-7204E 0.00353632915276031 9.8509E-20 24.230 4.00 1.9818423 2.256844820 0.0003152 0.154893 MSP-GC
J1216-6410 0.003539375658423 1.62E-21 47.40 1.71 2.937091 4.03672718 6.8E-6 0.155852 MSP
J1933-6211 0.003543431438847 0.37E-20 11.499 0.63 12.281575 12.81940650 1.2E-6 0.323653 MSP
J1850+0124 0.003559763768 1.09E-20 118.89 2.97 34.00102 84.949858 6.90E-5 0.246062 MSP
J1748-2446M 0.00356957 0 238.65 * 0.596 0.4431 0 0.16 MSP-GC
J2234+06 0.003570 * 10.8 * 14 32 0.13 0.19 MSP
J1545-4550 0.00357528861884712 5.25E-20 68.4 2.01 3.8469053 6.203064928* 1.3E-5 0.153107 MSP
J1514-4946 0.00359 * 31.5 1.27 * * * * MSP
J1855-14 0.003590 * 109.2 * 0 0 * * MSP
J1701-3006B 0.00359385 -3.4978e-19 113.44 * 0.25277 0.14455 <0.00007 0.14 RB-GC
J1600-3053 0.00359792850865547 9.5004E-21 52.3262 2.40 8.801652 14.3484577709 17.369E-5 0.204856 MSP
J1902-70 0.00360 * 19.5 1.12 * * * * MSP
J1944+2236 0.003617993078 7.5E-21 185.45 8.46 * * * * MSP
J1911+0102A 0.00361852 -6.58e-21 202.678 * 0.03766 0.140996 <0.00013 0.020 BW-GC
J1801-1417 0.003625096660 5.31E-21 57.21 1.80 * * * * MSP
J1911-1114 0.0036257455713977 1.416E-20 30.9750 1.59 1.762875 2.71655761 1.9E-5 0.119864 MSP
J1828+0625 0.00363 * 22.4 1.18 * 6.0 * * MSP
J2234+0944 0.00363 * 17.8 * 0.068 0.420 * 0.016 BW-F
J0024-7204P 0.00364302 0 24.3 * 0.0380 0.1472 0.0 0.02 BW-GC
J1740-5340 0.00365033 1.68e-19 71.8 * 1.65284 1.35406 <0.0001 0.22 RB-GC
J1748-2446ae 0.00365859 0 238.75 * 0.0406 0.17073 0 0.019 BW-GC
J0023-7205M 0.00367664 -3.844e-20 24.42 * * * * * MSP-GC
J1231-1411 0.003683878711 2.280E-20 8.090 0.45 2.042633 1.860143882 4E-6 0.183932 MSP
J1147-66 0.00372 * 133.8 4.26 * * * * MSP
J1641+3627C 0.003722 0 30.1 * * * * * MSP-GC
J2129-5721 0.003726348482 2.08534E-20 31.853 0.40 3.5005674 6.625493093 1.21E-5 0.132090 MSP
J1801-0857C 0.003739 0 182.4 * * * * * MSP-GC
J1741+1351 0.0037471544 * 24.0 1.41 11.03 16.335 * 0.238883 MSP
J1302-32 0.00377 * 26.2 1.86 * * * * MSP
J1905+0400 0.0037844047882356 4.9052E-21 25.6923 1.33 * * * * MSP
J1652-48 0.0037851238 * 187.8 4.79 * * * * MSP
J1923+2515 0.003788155519 9.42E-21 18.85766 0.99 * * * * MSP
J1748-2021F 0.00379363 -1.055e-20 220.43 * 9.49757 9.83397 0.0531 0.35 MSP-GC
J1622-03 0.00385 * 10.8 * * * * * MSP
J0610-2100 0.0038613247042986 0.00001235E-15 60.6662 5.64 0.073488 0.2860160010 * 0.021397 BW-F
J1835-3259 0.003889 0 63.35 * * * * * MSP-GC
J1751-2857 0.003914873196 1.126e-20 42.808 1.44 32.528221 110.7464576 0.0001283 0.192849 MSP
J1824-2452I 0.0039318526 0 119.0 * 0.76591 0.45940754 0.0 0.174 RB-GC+AMXP
J2019+2425 0.003934524080 7.0237E-21 17.203 0.91 38.7676297 76.51163479 0.00011109 0.308635 MSP
J1937+16 0.003960 * 105.9 * 0 0 * * MSP
J1957+25 0.003960 * 44.1 * 0.283 0.238 * * MSP
B2127+11F 0.00402704 3.2e-20 65.52 * * * * * MSP-GC
J0024-7204Q 0.00403318 3.402e-20 24.29 * 1.46221 1.18908 0.000085 0.21 MSP-GC
J1824-2452J 0.004039 0 119.2 * 0.0250 0.0974 0.0 0.015 BW-GC
J0024-7204G 0.00404038 -4.215e-20 24.441 * * * * * MSP-GC
J0509+08 0.00406 * 38.3 * * * * * MSP
J1824+10 0.00407 * 59.9 * * * * * MSP
J1744-1134 0.004074545940854022 8.93496E-21 3.13908 0.42 * * * * MSP
J1853+1303 0.00409179738145616 8.7163E-21 30.5701 1.60 40.7695198 115.65378643 2.3691E-5 0.239536 MSP
J1824-2452L 0.0041 0 119.0 * 0.0570 0.22571 0.0 0.022 BW-GC
J1431-5740 0.004110543956 6.42E-21 131.46 4.07 2.269890 2.726855823 4.3E-6 0.156496 MSP
J1824-2452C 0.004159 0 120.7 * 7.356 8.078 0.847 0.30 MSP-GC
J1737-0811 0.004175017312 7.93E-21 55.311 2.38 9.332791 79.517379 5.38E-5 0.065143 MSP
J1844+0115 0.004185543936664 1.07E-20 148.22 3.45 14.173495 50.6458881 0.0002578 0.138203 MSP
J1807-2459B 0.004186 0 137.3 * 28.7895 9.95667 0.7470 1.47 MSP-GC-DNS
J1122+78 0.004200 * 11.2 * * * * * MSP
J1125+7819 0.004200 * 11.2 * 12.192 15.355 * * MSP
J1935+1726 0.004200 * 62.0 * * * * * MSP
J1748-2446W 0.00420518 0 239.14 * 5.869 4.877 0.015 0.34 MSP-GC
J1801-0857D 0.004226532003547 6.9E-21 174.71 10.60 * * * * MSP-GC
J1312+0051 0.00423 * 15.3 1.15 * 38.5 * * MSP
J2047+1053 0.00429 * 34.6 2.23 * 0.12 * 0.035 BW-F
J1950+24 0.004300 * 142.2 * * * * * MSP
J0024-7203U 0.00434283 9.523e-20 24.335 * 0.52695 0.42911 0.00015 0.14 MSP-GC
J0024-7204L 0.00434617 -1.2206e-19 24.38 * * * * * MSP-GC
J0533+67 0.00439 * 57.4 5.80 * * * * MSP
J1823-3021E 0.004394 0 91.4 * * * * * MSP-GC
J1803-3002B 0.004397 0 192.6 * * * * * MSP-GC
J1813-2617 0.004430 * 122.5 * * * * * MSP
J1748-2446ag 0.00444803 0 237.75 * * * * * MSP-GC
J1824-2452K 0.004461 0 119.8 * 2.6050 3.91034 0.00152 0.16 MSP-GC
J1850+02 0.004480 * 540.5 * * * * * MSP
J1708-3506 0.004505158948 2.3E-20 146.8 3.50 33.584233 149.13318 0.0002445 0.161026 MSP
J2051-0827 0.0045086417449716 1.2737E-20 20.7449 1.28 0.045052 0.0991102506 0.0000 0.026657 BW-F
J2042+02 0.004530 * 9.3 * * * * * MSP
J0024-7204Z 0.004554 0 24.47 * * * * * MSP-GC
J1713+0747 0.004570136525 8.5289E-21 15.9915 1.05 32.34242099 67.8251298718 0.0000749406 0.275268 MSP
J1910-5959E 0.00457177 -4.37e-19 33.29 * * * * * MSP-GC
J1643-1224 0.004621641516 1.84628E-20 62.4121 0.42 25.072614 147.01739776 50.578E-5 0.119111 MSP
J1911+1347 0.004625962465 1.712E-20 30.99 1.60 * * * * MSP
J1824-2452H 0.004629 0 121.5 * 0.7195 0.435 0.0 0.20 RB-GC
J1709+2313 0.0046311962778409 0.00000363E-15 25.3474 1.83 15.288544 22.71189238 0.0000187 0.269165 MSP
J0931-19 0.004640 * 41.5 NA NA NA NA NA MSP
B2127+11E 0.00465144 1.78e-19 66.51 * * * * * MSP-GC
J1048+23 0.004670 * 16.7 * * * * * MSP
J1239+3232 0.004700 * 16.8 * 0 0 * * MSP
J1826-24 0.00470 * 81.9 * * * * * MSP
J1748-2446D 0.00471398 0 243.83 * * * * * MSP-GC
J0024-7204X 0.004771 0 24.0 * * * * * MSP-GC
J1725-3853 0.004791822704 5E-20 158.2 3.44 * * * * MSP
B2127+11D 0.0048028 -1.075e-18 67.28 * * * * * MSP-GC
J2322+2057 0.004808428209 9.70E-21 13.372 0.78 * * * * MSP
J0024-7204V 0.00481 0 24.1 * 0.85 0.227 0.0 * MSP-GC
J1207-5050 0.00484 * 50.6 2.19 * * * * MSP
J1823-3021F 0.00485 0 86.7 * * * * * MSP-GC
J0030+0451 0.0048654532073692 1.01736E-20 4.333 0.28 * * * * MSP
J1955+2527 0.004872765862 9.12E-21 209.971 9.06 * * * * MSP
J1953+1846A 0.004888 0 117 * 0.0782 0.1766 0.0 0.032 BW-GC
J1900+0308 0.004909239016418 5.9E-21 249.898 5.27 6.716377 12.47602144 * 0.168943 MSP
J1748-2446H 0.00492589 0 238.13 * * * * * MSP-GC
J2124-3358 0.004931114940 2.05705E-20 4.601 0.30 * * * * MSP
J1748-2446ah 0.00496515 0 237.75 * * * * * MSP-GC
J1905+0154B 0.004968 0 192 * * * * * MSP-GC
J1910+1256 0.00498358394056511 9.686E-21 38.0701 1.95 21.1291036 58.466742029 2.3018E-4 0.191675 MSP
J0514-4002 0.00499058 1.17e-21 52.1489 * 36.2966 18.7852 0.88798 1.1 MSP-GC
J1748-2446R 0.00502854 0 237.60 * * * * * MSP-GC
J1142+0119 0.00507 * 19.2 2.04 * 1.58 * * MSP
J1934+22 0.00508 NA 174.1 * * * * * MSP
J1943+22 0.005080 * 174.1 NA NA NA NA NA MSP
J1748-2446ac 0.00508691 0 238.72 * * * * * MSP-GC
J1835-0114 0.005116387644239 0.7E-20 98 2.67 4.654423 6.6925427 1.1E-5 0.178042 MSP
J1748-2446ab 0.00511971 0 238.34 * * * * * MSP-GC
J1750-3703D 0.005139936774902 4.928E-19 230.09 11.70 * * * * MSP-GC
J1024-0719 0.005162204637 1.852E-20 6.48520 0.49 * * * * MSP
J1944+0907 0.0051852019041260 1.713E-20 24.34 1.28 * * * * MSP
J2302+4442 0.005192324646 13.3E-21 13.762 0.75 51.429942 125.935292 0.00050328 0.291704 MSP
J2010-1323 0.005223271015 0.482E-20 22.160 1.29 * * * * MSP
J1701-3006A 0.00524157 -1.3196e-19 115.03 * 3.48372 3.80595 0.00000 0.23 MSP-GC
J1012+5307 0.005255749014 1.71342E-20 9.0233 0.70 0.5818172 0.60467271355 * 0.107084 MSP
J1911-6000C 0.00527733 2.2e-21 33.21 * * * * * MSP-GC
J1732-5049 0.00531255028907845 1.4207E-20 56.822 1.81 3.9828705 5.262997206 8.7E-6 0.178890 MSP
J0024-7204D 0.00535757 -3.429e-21 24.729 * * * * * MSP-GC
B1855+09 0.005362 1.784055E-20 13.300 0.90 9.2307805 12.32719 2.170E-5 0.241445 MSP
J1911+0101B 0.00538432 -2e-21 196.69 * * * * * MSP-GC
J1824-2452E 0.00542 0 119.8 * * * * * MSP-GC
B1820-30A 0.00544 3.385e-18 86.8 * * * * * MSP-GC
J1342+2822D 0.005443 0 26.34 * 38.524 128.752 0.0753 0.21 MSP-GC
J1843-1442 0.005470 * 114.6 * * * * * MSP
J0711-6830 0.00549096850013900 1.49067E-20 18.4066 1.04 * * * * MSP
J1748-2446F 0.00554014 0 239.18 * * * * * MSP-GC
J1120-3618 0.005550 * 45.1 * * * * * MSP
B1516+02A 0.00555359 4.122e-20 30.08 * * * * * MSP-GC
J0023-7204C 0.00575678 -4.985e-20 24.599 * * * * * MSP-GC
J0437-4715 0.005757451924362137 5.729370E-20 2.64476 0.16 3.36669708 5.74104646 1.9180E-5 0.140287 MSP
J1748-2446aa 0.00578804 0 237.42 * * * * * MSP-GC
J1719-1438 0.0057901517700238 8.043E-21 36.862 1.64 0.0018212 0.0907062900 0.0008 0.001129 MSP-
J1453+1902 0.005792302734 1.162E-20 14.049 0.95 * * * * MSP
J1803-3002C 0.00584 0 194.5 * * * * * MSP-GC
J1646-2142 0.00585 * 29.8 1.41 * 23 * * MSP
J1738+0333 0.0058500957646929 2.409E-20 33.778 1.97 0.343430 0.3547907344 4.0E-6 0.089458 MSP
J1824-2452G 0.005909 0 119.4 * 0.0165 0.1046 0.0 0.011 BW-GC
J2033+17 0.0059489575 1.1E-20 25.2 1.38 20.163 56.308 0.00013 0.187192 MSP
J1629-6902 0.006000603443 1.00E-20 29.490 1.36 * * * * MSP
J1750-3703B 0.00607454 1.92e-20 234.391 * 2.8659 3.60511 0.00404 0.19 MSP-GC
J1748-2446S 0.00611664 0 236.26 * * * * * MSP-GC
B1953+29 0.006133166510 2.9720E-20 104.501 5.39 31.4126903 117.34909728 3.3025E-4 0.178033 MSP
B1257+12 0.006218531948 1.143341E-19 10.16550 0.60 0.0000030 25.262 0.0 0.000000 MSP-planet
J1748-2021C 0.00622693 -5.984e-20 226.95 * * * * * MSP-GC
J1552-4937 0.006280 * 114.6 * * * * * MSP
J1824-2452B 0.006547 0 119.5 * * * * * MSP-GC
B2127+11H 0.00674339 2.4e-20 67.15 * * * * * MSP-GC
J2236-5527 0.006907549392921 9.6E-21 20.0 2.03 8.775877 12.68918715 5.02E-5 0.223460 MSP
J1748-2446T 0.00708491 0 237.70 * * * * * MSP-GC
J1549-06 0.00709 * 21.6 1.46 * * * * MSP
J1551-0658 0.007090 * 21.6 * 4.331 5.207 * * MSP
J1803-30 0.007101 0 192 * * * * * MSP-GC
J1801-0857A 0.007176 0 183.0 * * * * * MSP-GC
J1801-3210 0.007453584373 0.265E-20 176.7 5.05 7.809320 20.7716995 3.0E-6 0.137926 MSP
J1045-4509 0.007474224226 1.76603E-20 58.1662 0.23 3.0151325 4.0835292547 2.37E-5 0.158989 MSP
J0024-7204T 0.007588479807364 2.9374E-19 24.39 4.00 1.33850 1.126176767 0.00040 0.167186 MSP-GC
J1405-4656 0.0076 13.9 * * * * * * MSP
J1701-3006C 0.00761285 -3.189e-20 114.56 * 0.19288 0.21500 <0.00006 0.08 MSP-GC
J2129-04 0.00762 * 16.9 1.03 * * * 0.37 RB-F
J1918-0642 0.00764587288390884 2.56944E-20 26.554 1.40 8.3504716 10.9131777486 1.991E-5 0.236399 MSP
J1902+03 0.007790 * 253.7 * * * * * MSP
J1546-59 0.00780 * 168.3 4.67 * * * * MSP
B1516+02B 0.00794694 -3.3e-21 29.47 * 3.04859 6.85845 0.13784 0.13 MSP-GC
J1455-3330 0.007987204796261 2.428E-20 13.5708 0.74 32.362222 76.1745676 0.0001700 0.252541 MSP
J1730-2304 0.00812279804398456 2.01836E-20 9.617 0.51 * * * * MSP
J1910-5959B 0.0083578 -7.99e-19 33.28 * * * * * MSP-GC
J1748-2446C 0.0084361 -6.06e-19 237 * * * * * MSP-GC
J1529-3828 0.00848628211574 2.70E-20 73.62 4.85 29.34054 119.674809 1.686E-4 0.163053 MSP
J1528-3828 0.008490 * 73.6 * 10.645 11.516 * * MSP
J1953+67 0.008570 * 57.0 * * * * * MSP
J1748-2446N 0.0086669 0 238.47 * 1.619 0.3855 0.000045 0.56 MSP-GC
J0645+51 0.00885 * 18.2 * * * * * MSP
J1757-5322 0.008869961227277 2.63E-20 30.817 1.36 2.086527 0.4533112381 4.0E-6 0.556733 MSP
J1910-5959D 0.00903529 9.63e-19 33.32 * * * * * MSP-GC
J1804-2717 0.009343030685703 4.089E-20 24.674 1.17 7.28145 11.1287115 3.5E-5 0.200373 MSP
J1435-6100 0.009347972210248 2.45E-20 113.7 3.25 6.184023 1.3548852170 1.05E-5 0.883724 MSP
J1337-6423 0.009423406713 2.0E-19 260.32 6.30 13.086499 4.78533407 2.00E-5 0.781589 MSP
J1748-2446I 0.00957019 0 238.73 * 1.818 1.328 0.428 0.24 MSP-GC
J0922-52 0.00968 * 122.4 3.76 * * * * MSP
J1748-3009 0.009684273 * 420.2 5.96 1.32008 2.9338198 * 0.083871 MSP
J0824+00 0.009860 * 34.6 * * * * * MSP
B1639+36A 0.0103775 0 30.36 * * * * * MSP-GC
J2140-2310A 0.0110193 -5.181e-20 25.0640 * 0.23494 0.17399 <0.00012 0.11 RB-GC
B1620-26 0.0110758 -5.4693e-20 62.8633 * 64.8095 191.443 0.02532 0.33 MSP-GC-planet
J0900-3144 0.0111096491573889 0.00004912E-15 75.702 0.82 17.248811 18.73763576 1.03E-5 0.357699 MSP
J1525-5544 0.0114 * 126.8 * * * * * MSP
J1748-2446A 0.0115632 -3.4e-20 242.1 * 0.11971 0.07565 0.0 0.10 RB-GC
J1618-39 0.011987313 * 117.5 4.76 10.24 22.8 * 0.172595 MSP
J1802-2124 0.0126475935865227 7.256E-20 149.6258 3.33 3.7188533 0.698889243381 2.47E-6 0.807308 MSP
J1755-3715 0.0128 * 167.4 * * * * * MSP
J2140-2310B 0.013 0 25.09 * >0.1 >0.8 >0.52 >0.02 MSP-GC
J1949+3106 0.013138183343 9.3913E-20 164.1264 7.78 7.288650 1.949535 0.00004306 0.795580 MSP
J1748-2021D 0.0134958 5.8678e-19 224.98 * 0.3972 0.28607 0.00 0.14 RB-GC
J1603-7202 0.014841952249 1.56296E-20 38.0471 1.64 6.8806610 6.3086296703 9.55E-6 0.286590 MSP
J0721-2038 0.01554 * 76.1 9.379 5.461 * * * MSP
J2145-0750 0.01605242391433660 2.97848E-20 8.9977 0.57 10.1641080 6.83893 1.930E-5 0.423197 MSP
J1748-2021E 0.016264003411125 3.124E-19 224.10 8.40 * * * * MSP-GC
J1022+1001 0.016452929950 4.3344E-20 10.2521 0.52 16.7654074 7.8051302826 9.700E-5 0.705295 MSP
J1748-2021B 0.0167601 -3.2913e-19 220.922 * 4.46699 20.5500 0.57016 0.090 MSP-GC
J1914+07 0.018510 * 224.7 * * * * * MSP
J1753-28 0.018620 * 298.4 * * * * * MSP
J1745-0952 0.019376303441 9.246E-20 64.474 2.38 2.378599 4.943453386 9.8E-6 0.107915 MSP
J1952+2630 0.020732360562672 4.2721E-18 315.338 13.67 2.798196 0.39187863896 4.09E-5 0.925732 MSP
J1748-2446ai 0.0212284 0 233.9 * 2.8088 0.85088 0.4400 0.57 MSP-GC
J1933+17 0.021510 * 156.6 * 13.674 5.156 * * MSP
J1748-2446G 0.0216719 0 237.57 * * * * * MSP-GC
J0737-3039A 0.0226993785996239 1.75993E-18 48.920 1.10 1.415032 0.10225156248 0.0877775 1.254327 MSP-DNS
B1802-07 0.0231009 4.7e-19 186.38 * 3.92059 2.61676 0.21206 0.35 MSP-GC
J1622-6617 0.023623444739 6.4E-20 87.94 4.66 0.979380 1.640635183 8.0E-6 0.092021 MSP
J2007+2722 0.024497388545933 9.611E-19 127.0 6.85 * * * * MSP
J0407+1607 0.025701739194 7.9E-20 35.65 4.07 106.45026 669.0704 0.0009368 0.190025 MSP
J1056-7117 0.0263096769824 6.3E-20 93.04 5.27 4.14855 9.1387994 1.3E-5 0.125985 MSP
J1750-3703C 0.0265687 -9.96e-19 230.67 * * * * * MSP-GC
J1502-6752 0.026744423767 2.9E-19 151.75 11.57 0.31756 2.4844570 6.6E-5 0.021887 MSP
J1726-2946 0.027080 * 60.9 * * * * * MSP
J1756-2251 0.028461588454 1.0171E-18 121.18 2.92 2.7564 0.319633898 0.180567 1.096102 MSP-DNS
J1439-5501 0.028634888190 1.418E-19 14.56 0.76 9.833404 2.117942520 4.99E-5 1.113745 MSP
J1038+0032 0.02885155795131 0.000067E-15 26.59 2.36 * * * * MSP
J0621+1002 0.028853860730 4.732E-20 36.6010 1.88 12.0320744 8.3186813 0.00245744 0.442896 MSP
J1801-0857B 0.0289616 0 181.94 * 34.2866 56.7893 0.034 0.40 MSP-GC
J1841+0130 0.0297727753332 8.17E-18 125.88 3.19 3.50409 10.471626 8.2E-5 0.095854 MSP
SAXJ1808.4-3658 0.00249377 6.2e-21 * * 0.0628 0.08375 * 0.043 AMXP
XTEJ1751-305 0.00229885 2.9e-20 * * 0.010 0.0295833 * 0.014 AMXP
XTEJ0929-314 0.00540541 * * * 0.00599 0.0304167 * 0.0083 AMXP
XTEJ1807-294 0.00526316 * * * 0.0048 0.0279167 * 0.0066 AMXP
XTEJ1814-338 0.00318471 * * * 0.3906 0.177917 * 0.17 AMXP
IGRJ00291+5934 0.00166945 8.3e-21 * * 0.065 0.1025 * 0.039 AMXP
HETEJ1900.1-2455 0.00265252 * * * 0.0184 0.0541667 * 0.016 AMXP
SwiftJ1756.9-2508 0.00549451 <6e-20 * * 0.00597 0.0404167 * 0.007 AMXP
AqlX-1 0.00181818 * * * A1 0.7875 * 0.6 AMXP
SAXJ1748.9-2021 0.00226244 * * * 0.388 0.365417 * 0.1 AMXP
NGC6440X-2 0.00485437 * * * 0.00622 0.0395833 * 0.0067 AMXP
IGRJ17511-3057 0.00408163 * * * 0.275 0.144583 * 0.13 AMXP
SwiftJ1749.4-2807 0.0019305 * * * 1.90 0.3675 * 0.59 AMXP
IGRJ17498-2921 0.00249377 * * * 0.365 0.16 * 0.17 AMXP

Recent Posts

Life in the Solar System and Beyond

One of the most difficult problems that science still needs to solve is the question of the origin of life. We have very strong evidence that life emerged on Earth around 3.7 billion years ago, when our planet was less than 1 billion years old. It is very exciting to notice that in the first billion year, the Earth resembled very closely what might be considered hell, with a molten surface, lava and very active volcanoes. Indeed that geologic era is known as “the Hadean” which takes its name from Hades, the Greek god of the underworld. Life emerged almost immediately after the surface of the Earth solidified and once the heavy asteroid and comet bombardment of the Earth ended.

Earth_formation

The Hadean Earth, 4 billion years ago. The surface is still partially molten and constantly hit by a heavy flow of comets and asteroids.

The heavy bombardment, which was produced by the migration of the giants planets in the Solar System, is also thought to have brought most of the water that exists on our planet (the asteroids being the primary source rather than comets). If it took such a relatively short time for life to emerge, does it mean that we were just lucky but life is a very complex and unlikely event or that life does indeed create itself very easily? Or perhaps life was brought to Earth from space (the so-called panspermia)?

It is well known that several kinds of microbes (mostly named “extremophiles”) can survive in acidic environments which are more corrosive than sulfuric acid. Some others can survive extreme temperatures well above 100 degrees Celsius or below -200 degrees Celsius. The same goes for high pressures, with bacteria found thriving at 400 times the pressure we’re used to (which would crush you in an instant).

The Tardigrade is a micro-animal that can withstand extreme conditions (although it is not an extremophile). It can survive in space, radioactive environments, boiling water, freezing temperatures close to absolute zero and can survive without a food/water source for more than 10 years.

The Tardigrade is a micro-animal that can withstand extreme conditions (although it is not an extremophile). It can survive in space, radioactive environments, boiling water, freezing temperatures close to absolute zero and can survive without a food/water source for more than 10 years.

However, one common mistake that is often made is to confuse the fact that life has spread basically everywhere on Earth, even in the most extreme environments, with the fact that life can form everywhere. Indeed the fact that we find microbes in such extreme environments on Earth means that life has an immense power to adapt to those conditions. Adaptation is an evolutionary process and has nothing to do with the origin of life which is an entirely different question. Indeed the theory of evolution is a well known and established scientific theory whereas the origin of life still lacks a complete explanation and there are only a number of hypotheses that still need experimental confirmation. There are more than 20 proposed scenarios which attempt to explain the origin of life on Earth. Many of those build upon the “primordial soup” idea of Haldane and Oparin, two scientists that in the 1920s proposed that the atmosphere of the early Earth, when exposed to an energy source (e.g., lightnings), can produce organic molecules that accumulate in the sea forming a “soup”. These molecules then start a chain of chemical reactions which ultimately lead to the formation of life. A famous attempt to verify this idea was made by Miller (and Urey) in 1953 who created several amino-acids (the building blocks of proteins and thus life) in a “soup” when injecting energy in a simulated early atmosphere of the Earth.

A scheme of the apparatus used by Miller to produce organic compounds and amino-acids in his experiment.

A scheme of the apparatus used by Miller to produce organic compounds and amino-acids in his experiment.

The Miller experiment has been criticized since the simulated conditions of the early atmosphere were probably not the correct ones as it emerged in later studies. Thus if Miller had used a simulated atmosphere with the right composition, his experiment might have failed to produce amino-acids, although more recent experiments have succeeded in producing some. Another interesting fact is that when Miller performed his experiment  he reported that about 10% of the carbon present in the simulated atmosphere was transformed into organic compounds. About 1 milligram of a few different types of amino-acids were created. After the death of Miller in 2007, the sealed vials of the experiment were opened and re-examined. It was found that there were way more amino-acids than those reported by Miller in the his work in 1953, so this experiment was even more successful than originally reported.  In any case, amino-acids are just organic compounds and in the past few years they have also been found in space and even on meteorites landed on the Earth’s surface. Such meteorites had experienced extreme temperatures of more than 1000 degrees Celsius while burning during their descent in the Earth’s atmosphere. Therefore amino-acids might possibly be quite widespread and resist to extreme physical conditions, at least in the Solar System. Could the amino-acids present in the “primordial soup” on Earth (provided there was really a primordial soup!) have been brought here by asteroids/comets/meteorites?  Whatever the answer is, it is worth noticing that there’s a gigantic leap between creating organic molecules and creating life. But what is life? The most elementary forms of life are very very simple and it is difficult to establish whether such systems, viruses for example, are really alive. Today science defines a living system as a complex with a body, a metabolism (i.e., life can take resources from the environments and transform them into useful energy) and the property of having inheritable information (e.g., RNA and DNA). However, the latest scientific evidence suggests that the distinction between life and non-life is blurred and continuous rather than discrete.

How can astrophysics help to shed new light on the problem of the origin of life? In the last decade there has been an increasing interest in planetary exploration with a particular emphasis on the search for life in the Solar System. In the past, a lot of research has focused on Mars, for the reason that it is a rather close planet with a possible similar history as the Earth. We do know that large seas and a thick atmosphere were present on the ancient Mars, whereas today water is found in relatively small quantities and only in form of ice. Since Mars had liquid water and a favorable position in the Solar System, i.e., it lies within the so-called “habitable zone”, it was and still is obvious to look for the presence of life on that planet.

An artistic impression of how the ancient Mars might have looked like with its large oceans and thicker atmosphere. The close resemblance with the Earth is striking. (

An artistic impression of how the ancient Mars might have looked like with its large oceans and thicker atmosphere. The close resemblance with the Earth is striking. (“AncientMars” by Ittiz – Own work. Licensed under CC BY-SA 3.0 via Commons)

However, the whole concept of “habitable zone” is rather debated in astronomy. This zone is defined as that region in a solar system where a planet with sufficient atmospheric pressure can support liquid water on its surface. A few decades ago it was pretty clear that only rocky planets like the Earth (and Mars) can satisfy this condition, since gas giants (e.g., Jupiter and Saturn) have a huge atmosphere that sits on a thick layer of liquid hydrogen and helium. There are then the icy dwarf planets like Pluto, which, however, are too far to receive enough energy from the Sun and are too small to have a dense atmosphere so they do not have any liquid water on their surface.

However, with further planetary exploration there is now mounting evidence that not only rocky planets might be able to host life, but also large moons around gas giants, even if those are well outside the “habitable zone”. There are at least three examples of such moons in the Solar System: Titan (the largest moon of Saturn), Europa and Callisto (two of the four large moons of Jupiter).

The three gas giant moons Europa and Callisto (orbiting Jupiter) and Titan (Saturn).

The three moons Titan (orbiting Saturn),  Europa and Callisto (orbiting Jupiter).

Titan was recently explored by the Cassini-Huygens mission (NASA and ESA) with the Huygens probe that landed on its surface in 2005. The data collected revealed the presence of large amounts of organic material (organic aerosol) and the existence of large lakes of methane, ethane and propane. Europa and Callisto instead are increasingly becoming the two most striking examples of potentially habitable worlds that we know. In the late ’90s Jupiter was visited by the Galileo orbiter (an ESA mission) and Callisto was found to behave like a perfect conductor. This implies that Callisto is a highly conductive sphere which means that Jupiter’s magnetic field  – which is 10x larger than Earth’s –  cannot penetrate inside Callisto which is able to deflect it, as perfect conductors do. This was interpreted as a sign that beneath its solid surface there must be a thick layer of more than 10 km made of highly conductive liquid. Since water ice is widespread on the surface of this moon and salty water is a highly conductive material, it has been proposed that a large ocean can be enclosed within Callisto’s solid crust.

Current model of Callisto, with an outer solid crust, an inner ocean of liquid salted water (in blue) and a solid core.

Current model of Callisto, with an outer solid crust, an inner ocean of liquid salted water (in blue) and a solid core.

Even more striking is the case of Europa, another moon of Jupiter. The current idea is that a large ocean exists here too underneath the solid surface. Astronomers have estimated the content of liquid water on this moon and have found that there should be more liquid water on Europa than on the whole Earth. This water is liquid instead of frozen because the tides that Jupiter exerts on these moons are huge and the internal friction heats up the water and keeps it in a liquid form.

Estimated total amount of salted water on Europa compared to Earth

Estimated total amount of salted water on Europa compared to Earth

Unfortunately we have no probes that can visit directly these alien oceans because the liquid water is enclosed within a thick shell of solid material which would be impossible to penetrate. Some water vapor plumes are, however, regularly emitted from the surface of this moon. Therefore analyzing the chemical content of the plumes might be a smart way around penetrating the solid surface. The plumes can be used as probes of the internal ocean and help to understand how the underneath environment might look like. Indeed one recently approved mission (the JUICE mission of ESA and NASA) will explore these plumes of Europa and the whole Jupiter system to assess potential habitability of those worlds and determine whether our current ideas are sound and can be applied to other gas giants (especially the many known beyond the Solar System).

But how can life form on Europa or other moons? There is an interesting hypothesis on the origin of life that proposes hydrothermal vents in the deep oceans of the Earth as the possible location for the creation of life. Deep oceanic vents release energy and heat up the environment with water that can reach up to 450 degrees Celsius. Such water creates a gradient of temperature that slowly decreases towards the deep ocean which has an average temperature of just a few degrees Celsius. There should be a shell around hydrothermal vents which has just the right temperature and composition to trigger chemical reactions that might lead to life. Something similar might be happening on Europa and other moons too? It’s still too early to say, but it is probable that we will find out pretty soon.

I just notice that when searching info on abiogenesis and related problems on google I was literally flooded by tens of websites of creationists, christian fundamentalists and so on. They seem to have figured all out: it must have been god. Right.

  1. Welcome to Pluto Leave a reply
  2. Welcome to Pluto 1 Reply
  3. 2014 in review Leave a reply
  4. Lightweight and Supermassive Black Holes Hidden in Galaxies 1 Reply
  5. Detecting the Sound of Neutron Stars Leave a reply
  6. Leave a reply
  7. Leave a reply
  8. The Super-Massive Black Hole Stays on a Diet Leave a reply
  9. What Are Neutron Stars Made Of? 1 Reply