W. Curdt

Hot emission lines (T_e > 3 x 10⁶ K) are normally not observed on the disk. However, during a flare
the plama temperatures can easily reach 3 x 10⁷ K. In spectra obtained during the May 9, 1999 flare
of size M8 more than 80 lines were observed, which include lines from Fe XVIII - Fe XXIII that
provide evidence of 10⁷ K plasmas. These are the hottest high-resolution astrophysical spectral
recordings ever made in the 500 Å - 1600 Å range. The line list is taken from Feldman et al. (2000,
ApJ 544, 508); the references in the last column pointing to the most accurate previous measurements
are also given therein.
 

Table: Flare lines in the SUMER spectral range.
 

Ion 0)	Transition		Measured l / Å	Previously known l / Å	Log Te 1)	References
Cr XVIII	2s22p3 2D3/2	- 2s22p34S3/2	793.160 ± 0.021	793.3±0.3	6.6	Hinnov et al. (1982)
Ni XIX	2s22p53s 3P0	- 2s22p53s3P1	794.605 ± 0.025		~6.6
Si XIII	1s2p 3P2	- 1s2s 3S1	814.715 ± 0.025	814.71±0.02; 814.729±0.024	6.952)	Howie et al. (1994); Curdt et al. (2000)
Co XIX	2s22p5 2P1/2	- 2s22p52P3/2	820.019 ± 0.025		6.65
Fe XX	2s22p3 2P1/2	- 2s22p32D3/2	821.706 ± 0.030	821.74±0.05	6.9	Kucera et al. (2000)
Fe XXII	2s22p 2P3/2	- 2s22p 3P1/2	845.570 ± 0.020	845.55±0.1	7.05	Hinnov & Suckewer (1980)
Ti XVI	2s22p3 2D3/2	- 2s22p34S3/2	861.799 ± 0.020	861.8±0.1	6.6	Hinnov (private communication)
Si XIII	1s2p 3P0	- 1s2s 3S1	878.690 ± 0.040	878.85; 878.684±0.029	6.952)	Howie et al. (1994); Curdt et al. (2000)
Ca XIV	2s22p3 2D5/2	- 2s22p34S3/2	880.401 ± 0.015	880.43±0.02	6.45	Feldman et al. (1998a)
Ni XXIII	2s22p2 3P1	- 2s22p23P0	910.855 ± 0.028	911.0	7.05	Hinnov et al. (1982)
Ti XV	2s22p4 1D2	- 2s22p43P2	919.730 ± 0.019	919.73±0.08	6.5	Peacock et al. (1984)
Ca XIV	2s22p3 2D3/2	- 2s22p34S3/2	943.585 ± 0.020	943.61±0.02	6.45	Feldman et al. (1998a)
K XIII	2s22p3 2D5/2	- 2s22p34S3/2	945.880 ± 0.020		6.35
S X	2s22p23p 4D7/2	- 2s22p23s3P5/2	946.307 ± 0.020	946.29±0.02	6.2	Kink & Engsröm (1999)
Ti XVI	2s22p32P3/2	- 2s22p32D3/2	968.868 ± 0.015	968.8±0.3	6.6	Hinnov (private communication)
Fe XVIII	2s22p5 2P1/2	- 2s22p52P3/2	974.850 ± 0.020	-; 974.86±0.02	6.7	Peacock et al (1984); Feldman et al. (1998a)
K XIII	2s22p3 2D3/2	- 2s22p34S3/2	994.442 ± 0.020		6.35
Mg XI	1s2p 3P2	- 1s2s 3S1	997.456 ± 0.015	997.38±0.08; 997.451±0.019	6.81)	Klein et al. (1985); Curdt et al. (2000)
Mn XXI	2s22p 2P§/2	- 2s22p 2P!/2	1005.862 ± 0.020		6.95
Ar XII	2s22p3 2D5/2	- 2s22p34S3/2	1018.790 ± 0.020	1018.87±0.02	6.3	Feldman et al. (1998a)
Ni XV	3s23p2 1S0	- 3s23p23P1	1033.041 ± 0.015	1033.04±0.02	6.35	Feldman et al. (1998a)
Ni XIV	3s23p3 2P3/2	- 3s23p34S3/2	1034.485 ± 0.020	1034.48±0.02	6.3	Feldman et al. (1998a)
Mg XI	1s2p 3P0	- 1s2s 3S1	1043.282 ± 0.020	1043.29±0.08; 1043±0.008	6.82)	Klein et al. (1985); Curdt et al. (2000)
Ar XII	2s22p3 2D3/2	- 2s22p34S3/2	1054.585 ± 0.015	1054.62±0.02	6.3	Feldman et al. (1998a)
?			1062.450 ± 0.040		>6.2
?			1077.172. ± 0.025		>6.2
Fe XXIII	2s2p 3P2	- 2s2p 3P1	1079.415 ± 0.025	1079.3±0.3	7.1	Hinnov et al. (1982)
Ca XIV /2	2s22p3 2P3/2	- 2s22p34S3/2	1090.450 ± 0.030 /2	545.26±0.02	6.45	Feldman et al. (1982)
Ca XV	2s22p2 1D2	- 2s22p23P1	1098.484 ± 0.040	1098.44±0.02	6.55	Feldman et al. (1998a)
Ca XV /2	2s22p2 1S0	- 2s22p23P1	1110.764 ± 0.040 /2		6.55
Na X	1s2p 3P2	- 1s2s 3S1	1111.754 ± 0.030	1111.759±0.017	6.72)	Curdt et al. (2000)
Fe XIX	2s22p4 3P1	- 2s22p43P2	1118.078 ± 0.015	1118.060±0.01	6.8	Peacock et al. (1984)
Ca XIII	2s22p4 1D2	- 2s22p23P2	1133.756 ± 0.020	1133.79±0.02	6.35	Feldman et al. (1998a)
Fe XX /2	2s22p3 2D5/2	- 2s22p34S3/2	1135.650 ± 0.025 /2	567.76; 567.84	6.9	Widing (1978); Kucera et al. (2000)
Fe XVII	2s22p53s 3P0	- 2s22p53s3P1	1153.151 ± 0.025	-; 1153.16 ± 0.02	6.45	Feldman et al. (1985); Feldman et al. (1998a)
Ca XIV /2	2s22p3 2P1/2	- 2s22p34S3/2	1159.706 ± 0.030 /2	579.85±0.02	6.45	Feldman et al. (1998a)
?			1164.813 ± 0.040		>6.2
Mn XVII	2s22p5 2P1/2	- 2s22p52P3/2	1167.760 ± 0.015		6.55
Fe XXI /2	2s22p2 1D2	- 2s22p23P1	1171.531 ± 0.030 /2	585.8±0.3	6.95	Hinnov et al. (1982)
Ni XIV	3s23p3 2P1/2	- 3s23p34S3/2	1174.656 ± 0.020	-; 1174.65 ± 0.02	6.3	Sandlin et al. (1977); Feldman et al. (1998a)
Fe XIX /2	2s22p4 1D2	- 2s22p43P2	1184.467 ± 0.030 /2	592.234±0.006	6.8	Peacock et al. (1984)
?			1188.108 ± 0.025		>6.2
?			1192.978 ± 0.040		>6.2
?			1201.192 ± 0.035		>6.2
Cr XX	2s22p 2P3/2	- 2s22p 2P1/2	1205.728 ± 0.025	1205.9±0.3	6.9	Hinnov et al. (1982)
Ne IX	1s2p 3P2	- 1s2s 3S1	1248.088 ± 0.015	1248.07±0.02; 1248.097±0.014	6.52)	Beyer et al. (1986); Curdt et al. (2000)
K XII	2s22p4 1D2	- 2s22p43P2	1256.484 ± 0.025		6.3
Ni XIII	3s23p4 1S0	- 3s23p43P1	1277.204 ± 0.025	-; 1277.22 ± 0.02	6.25	Sandlin et al. (1977); Feldman et al. (1998a)
Ne IX	1s2p 3P0	- 1s2s 3S1	1277.790 ± 0.050	1277.71±0.02	6.52	Brown et al. (1985)
Ca XIV	2s22p3 2P3/2	- 2s22p32D3/2	1291.607 ± 0.030	1291.61±0.02	6.45	Feldman et al. (1998a)
Ca XIII /2	2s22p4 1S0	- 2s22p43P1	1297.398 ± 0.030 /2	648.68±0.02	6.35	Feldman et al. (1998a)
Ar XII	2s22p3 2P3/2	- 2s22p34S3/2	1298.186 ± 0.040		6.3
? / 2			1308.146 ± 0.030 /2		>6.2
? / 2			1309.752 ± 0.030 /2		>6.2
Ar XIII /2	2s22p2 1S0	- 2s22p23P1	1313.344 ± 0.020 /2	656.69±0.020	6.4	Feldman et al. (1998a)
? /2			1314.650 ± 0.040 /2		>6.2
? /2			1320.402 ± 0.025 /2		>6.2
Cr XVIII /2	2s22p3 2D5/2	- 2s22p34S3/2	1325.901 ± 0.030 /2	663.1±0.3	6.75	Denne & Hinnov (1984)
Fe XIX	2s22p4 3P0	- 2s22p43P2	1328.791 ± 0.030		6.8
Ar XIII	2s22p2 1D2	- 2s22p23P1	1330.532 ± 0.030	1330.54±0.02	6.4	Feldman et al. (1998a)
(f)			1331.503 ± 0.021	1331.48±0.02	>6.2	Feldman et al. (1998b)
Ar XII /2	2s22p3 2P1/2	- 2s22p34S3/2	1340.603 ± 0.020 /2	670.34±0.02	6.3	Feldman et al. (1998a)
Fe XXI	2s22p2 3P1	- 2s22p23P0	1354.064 ± 0.020	1354.1±0.1	6.95	Doschek et al. (1975)
Mn XVIII	2s22p4 3P1	- 2s22p43P2	1354.892 ± 0.025		6.75
Fe XX /2	2s22p3 2P3/2	- 2s22p32D5/2	1358.537 ± 0.029 /2	679.29	6.9	Kucera et al. (2000)
Ca XV	2s22p2 1D2	- 2s22p23P2	1375.959 ± 0.035		6.55	Feldman & Doschek (1977), Sandlin et al. (1977)
Ar XI	2s22p4 1D2	- 2s22p43P2	1392.095 ± 0.017	1392.12	6.2	Feldman & Doschek (1977), Sandlin et al. (1977)
Cr XVI	2s22p5 2P1/2	- 2s22p53P3/2	1410.584 ± 0.025	1410.62±0.02	6.45	Peacock et al. (1984)
Ca XIV	2s22p3 2P3/2	- 2s22p32D5/2	1432.228 ± 0.050		6.45
Ar XI /2	2s22p3 3p5P3	- 2s22p3 3s5S2	1435.705 ± 0.040 /2	717.88±0.02	6.2	Kink (1999)
Fe XX /2	2s22p3 2D3/2	- 2s22p34S3/2	1443.107 ± 0.025 /2	721.55±0.02	6.9	Kucera et al. (2000)
?			1452.655 ± 0.040		>6.2
Ar XI /2	2s22p3 3p5P2	- 2s22p3 3s5S2	1460.877 ± 0.030 /2	730.41	6.2	Kink (1999)
Ar XI /2	2s22p3 3p5P1	- 2s22p3 3s5S2	1472.980 ± 0.040 /2	736.55	6.2	Kink (1999)
Cr XVII /2	2s22p4 1D2	- 2s22p43P2	1481.479 ± 0.020 /2	740.75±0.03	6.6	Peacock et al. (1984)
Ar XI	2s22p4 1S0	- 2s22p43P1	1491.605 ± 0.020		6.2
Ca XIV	2s22p3 2P1/2	- 2s22p32D3/2	1504.275 ± 0.032		6.45
?			1515.190 ± 0.060		>6.2
Mn XIX /2	2s22p3 2D3/2	- 2s22p34S3/2	1517.180 ± 0.040 /2		6.9
Ni XXI /2	2s22p4 3P1	- 2s22p43P2	1558.901 ± 0.030 /2	779.5±0.3	6.9	Hinnov et al. (1982)
Fe XXI /2	2s22p2 1D2	- 2s22p23P2	1572.061 ± 0.030 /2	786.1±0.3	6.95	Hinnov et al. (1982)
Fe XX+ Cr XVIII /2	2s22p3 2P3/2 2s22p3 2D3/2	- 2s22p32P1/2  - 2s22p3 4S3/2	1586.309 ± 0.030 & 1586.309 /2	1586.29 ± 0.03 793.3±0.3	6.9 6.75	Kucera et al. (2000) Hinnov et al. (1982)
Ni XIX /2	2s22p53s 3P0	- 2s22p53s3P1	1589.256 ± 0.035		~6.6

^{0 Unidentified lines are noted by question mark or by the temperature classification of Feldman et al. (1998b), if available. Second order lines are noted by /2.}

^{I In all other than the He-like ions the temperature of maximum fractional abundance is given.}

^{2For all He-like lines the given values represents the temperature at which the contribution function reaches maximum.}